I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
John,
MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what has been called the One True Rule. The usual name for the implementation is Full Doppler Tuning. You are doing it right. When everyone does this, it provides a very pleasant opportunity to talk instead of tune. It also keeps from drifting all over another QSO, though the transponders are seldom full these days.
However, that is not to say that people not using this are doing it wrong, exactly. There are still many rigs in use which do not have the capability for computer frequency control. In the old days, the rule was to tune the highest frequency, whether uplink or downlink, since this is where the Doppler shift is greatest. Take a look at KB5MU's original article and updates here:
http://www.amsat.org/amsat/features/one_true_rule.html
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Belstner Sent: Monday, May 31, 2010 3:36 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Doppler Tuning Convention Question
I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
At 08:06 AM 6/1/2010, Alan P. Biddle wrote:
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
I agree with this suggestion. I'm setting up for full Doppler tuning myself on 2m and 70cm. Got the radio (FT-736R) and the interface cables in, but have to install some antennas and the PC for Doppler control. Looking forward to giving the SSB birds a try without having to fiddle with the VFO all the time (I have worked the Fujis in the past with manual tuning, it can be a pain LOL).
73 de VK3JED / VK3IRL http://vkradio.com
Alan, John and all,
There is no question that computer-controlled Doppler tuning makes working the linear satellites easier. That being said, I am glad that my lack of a computer to dedicate to ham radio forced me to learn and use manual tuning by following the one true rule of always tuning the higher frequency.
These days, I often use SatPC 32 for computer control when I use my two FT-817 QRP rigs for the satellites. But last year, right after Field Day, the CAT plug on my FT-857D stopped working. Because of the choices I've made about my station setup (i.e., a totally portable station that I can set up and operate anywhere at any time), I need to use the 857 as a transmit radio in order to work the DX into Europe and Africa that I have on AO-7 Mode B. And without its higher power on 2 meters, I would not have gotten Hawaii into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the CAT plug died on the 857, I have been manually tuning on every pass during which I use that radio.
I really like being able to do it, even if I don't have to. I hope new satellite operators will take the time to at least develop the basic ability to effectively use manual tuning. But then - dinosaur that I am - I also wish more amateurs in general would at least learn Morse Code at slow speeds ... hihi.
And since we're on the topic ... has anyone else noticed that the latest edition of "The ARRL Satellite Handbook" uses VO-52 as the example for Doppler tuning - and that it suggests that newcomers who are manually tuning for Doppler park their transmit frequency on the UHF uplink and tune the VHF downlink (i.e., the exact opposite of the One True Rule)? That is really mystifying and disappointing.
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan P. Biddle Sent: Monday, May 31, 2010 6:07 PM To: 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
John,
MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what has been called the One True Rule. The usual name for the implementation is Full Doppler Tuning. You are doing it right. When everyone does this, it provides a very pleasant opportunity to talk instead of tune. It also keeps from drifting all over another QSO, though the transponders are seldom full these days.
However, that is not to say that people not using this are doing it wrong, exactly. There are still many rigs in use which do not have the capability for computer frequency control. In the old days, the rule was to tune the highest frequency, whether uplink or downlink, since this is where the Doppler shift is greatest. Take a look at KB5MU's original article and updates here:
http://www.amsat.org/amsat/features/one_true_rule.html
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Belstner Sent: Monday, May 31, 2010 3:36 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Doppler Tuning Convention Question
I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Tim,
Speak for yourself :-) In the 20+ years I have been a satellite operator, I have never gotten computer doppler control to work right on the linear birds. It works great on FM, but I always wind up fighting it on the linear birds. As soon as I tune the other guy in the computer moves me off frequency. It's so much easier to just listen and adjust on the fly.
Maybe there is some secret, but I have yet to be clued in... If someone wants to write a "Dummies Guide" for this I would be willing to be your test subject.
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tim - N3TL Sent: Monday, May 31, 2010 8:42 PM To: APBIDDLE@mailaps.org; 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, John and all,
There is no question that computer-controlled Doppler tuning makes working the linear satellites easier. That being said, I am glad that my lack of a computer to dedicate to ham radio forced me to learn and use manual tuning by following the one true rule of always tuning the higher frequency.
These days, I often use SatPC 32 for computer control when I use my two FT-817 QRP rigs for the satellites. But last year, right after Field Day, the CAT plug on my FT-857D stopped working. Because of the choices I've made about my station setup (i.e., a totally portable station that I can set up and operate anywhere at any time), I need to use the 857 as a transmit radio in order to work the DX into Europe and Africa that I have on AO-7 Mode B. And without its higher power on 2 meters, I would not have gotten Hawaii into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the CAT plug died on the 857, I have been manually tuning on every pass during which I use that radio.
I really like being able to do it, even if I don't have to. I hope new satellite operators will take the time to at least develop the basic ability to effectively use manual tuning. But then - dinosaur that I am - I also wish more amateurs in general would at least learn Morse Code at slow speeds ... hihi.
And since we're on the topic ... has anyone else noticed that the latest edition of "The ARRL Satellite Handbook" uses VO-52 as the example for Doppler tuning - and that it suggests that newcomers who are manually tuning for Doppler park their transmit frequency on the UHF uplink and tune the VHF downlink (i.e., the exact opposite of the One True Rule)? That is really mystifying and disappointing.
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan P. Biddle Sent: Monday, May 31, 2010 6:07 PM To: 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
John,
MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what has been called the One True Rule. The usual name for the implementation is Full Doppler Tuning. You are doing it right. When everyone does this, it provides a very pleasant opportunity to talk instead of tune. It also keeps from drifting all over another QSO, though the transponders are seldom full these days.
However, that is not to say that people not using this are doing it wrong, exactly. There are still many rigs in use which do not have the capability for computer frequency control. In the old days, the rule was to tune the highest frequency, whether uplink or downlink, since this is where the Doppler shift is greatest. Take a look at KB5MU's original article and updates here:
http://www.amsat.org/amsat/features/one_true_rule.html
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Belstner Sent: Monday, May 31, 2010 3:36 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Doppler Tuning Convention Question
I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
me too. i do only manual tuning and experienced same problem. i also prefer to manually move my rotor as crossing the end of rotation always has it magically move 360 degrees at the time you either hear the best or just went to work someone.
73...bruce
Sent from my iPhone
On May 31, 2010, at 9:05 PM, "Gary "Joe" Mayfield" <gary_mayfield@hotmail.com
wrote:
Tim,
Speak for yourself :-) In the 20+ years I have been a satelliteoperator, I have never gotten computer doppler control to work right on the linear birds. It works great on FM, but I always wind up fighting it on the linear birds. As soon as I tune the other guy in the computer moves me off frequency. It's so much easier to just listen and adjust on the fly.
Maybe there is some secret, but I have yet to be clued in... If someone wants to write a "Dummies Guide" for this I would be willing to be your test subject.
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tim - N3TL Sent: Monday, May 31, 2010 8:42 PM To: APBIDDLE@mailaps.org; 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, John and all,
There is no question that computer-controlled Doppler tuning makes working the linear satellites easier. That being said, I am glad that my lack of a computer to dedicate to ham radio forced me to learn and use manual tuning by following the one true rule of always tuning the higher frequency.
These days, I often use SatPC 32 for computer control when I use my two FT-817 QRP rigs for the satellites. But last year, right after Field Day, the CAT plug on my FT-857D stopped working. Because of the choices I've made about my station setup (i.e., a totally portable station that I can set up and operate anywhere at any time), I need to use the 857 as a transmit radio in order to work the DX into Europe and Africa that I have on AO-7 Mode B. And without its higher power on 2 meters, I would not have gotten Hawaii into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the CAT plug died on the 857, I have been manually tuning on every pass during which I use that radio.
I have seen it work with Sat PC 32 on VO52 Arm chair copy just move the antenna once in a while. This was out doors, using a small ACER computer and arrow antenna.
I would like to try it on my ICom 720, but the data port does not work just like everything else that is satellite related to that radio. When we get a HEO I will consider replacing the 720, until then no sense in trying another radio with features that do not match the needs of the operators.
Art, KC6UQH
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gary "Joe" Mayfield Sent: Monday, May 31, 2010 7:05 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Tim,
Speak for yourself :-) In the 20+ years I have been a satellite operator, I have never gotten computer doppler control to work right on the linear birds. It works great on FM, but I always wind up fighting it on the linear birds. As soon as I tune the other guy in the computer moves me off frequency. It's so much easier to just listen and adjust on the fly.
Maybe there is some secret, but I have yet to be clued in... If someone wants to write a "Dummies Guide" for this I would be willing to be your test subject.
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tim - N3TL Sent: Monday, May 31, 2010 8:42 PM To: APBIDDLE@mailaps.org; 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, John and all,
There is no question that computer-controlled Doppler tuning makes working the linear satellites easier. That being said, I am glad that my lack of a computer to dedicate to ham radio forced me to learn and use manual tuning by following the one true rule of always tuning the higher frequency.
These days, I often use SatPC 32 for computer control when I use my two FT-817 QRP rigs for the satellites. But last year, right after Field Day, the CAT plug on my FT-857D stopped working. Because of the choices I've made about my station setup (i.e., a totally portable station that I can set up and operate anywhere at any time), I need to use the 857 as a transmit radio in order to work the DX into Europe and Africa that I have on AO-7 Mode B. And without its higher power on 2 meters, I would not have gotten Hawaii into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the CAT plug died on the 857, I have been manually tuning on every pass during which I use that radio.
I really like being able to do it, even if I don't have to. I hope new satellite operators will take the time to at least develop the basic ability to effectively use manual tuning. But then - dinosaur that I am - I also wish more amateurs in general would at least learn Morse Code at slow speeds ... hihi.
And since we're on the topic ... has anyone else noticed that the latest edition of "The ARRL Satellite Handbook" uses VO-52 as the example for Doppler tuning - and that it suggests that newcomers who are manually tuning for Doppler park their transmit frequency on the UHF uplink and tune the VHF downlink (i.e., the exact opposite of the One True Rule)? That is really mystifying and disappointing.
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan P. Biddle Sent: Monday, May 31, 2010 6:07 PM To: 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
John,
MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what has been called the One True Rule. The usual name for the implementation is Full Doppler Tuning. You are doing it right. When everyone does this, it provides a very pleasant opportunity to talk instead of tune. It also keeps from drifting all over another QSO, though the transponders are seldom full these days.
However, that is not to say that people not using this are doing it wrong, exactly. There are still many rigs in use which do not have the capability for computer frequency control. In the old days, the rule was to tune the highest frequency, whether uplink or downlink, since this is where the Doppler shift is greatest. Take a look at KB5MU's original article and updates here:
http://www.amsat.org/amsat/features/one_true_rule.html
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Belstner Sent: Monday, May 31, 2010 3:36 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Doppler Tuning Convention Question
I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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This thread is cyclic but it is ok to be revisited time to time.
excerpt:
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
excerpt:
Tim,
Speak for yourself :-) In the 20+ years I have been a satelliteoperator, I have never gotten computer doppler control to work right on the linear birds. It works great on FM, but I always wind up fighting it on the linear birds. As soon as I tune the other guy in the computer moves me off frequency. It's so much easier to just listen and adjust on the fly.
73, Joe kk0sd
excerpt:
And since we're on the topic ... has anyone else noticed that the latest edition of "The ARRL Satellite Handbook" uses VO-52 as the example for Doppler tuning - and that it suggests that newcomers who are manually tuning for Doppler park their transmit frequency on the UHF uplink and tune the VHF downlink (i.e., the exact opposite of the One True Rule)? That is really mystifying and disappointing.
73 to all,
Tim - N3TL
The one "true rule" is fine when your "Highest" frequency is your downlink frequency "The frequency you adjust at your transceiver" and the ARRL satellite handbook is giving the correct way with AO-52 i will try to explain it below for the linear satellite.
Those who are fully auto doppler controlled always correct their uplink and downlink frequency to be at the same spot on the satellite to maintain the same audio pitch. Under normal standard work we should all adjust the audio for "normal voice" but some prefer high pitch voice and some low pitch voice. Auto doppler correction can be set to maintain your audio pitch preference but if the other station adjust his station for a low pitch it can be annoying for some operator who prefer high pitch voice (Ore vice versa) but it can be corrected just in cheating your RX base frequency a bit.
The main issue:
If you enter in a QSO with a fully doppler corrected station and you follow the "One true rule" it is fine but not if this highest frequency is your TX frequency. When you adjust your uplink (TX) frequency you will change the normal frequency the receiving station PC doppler tracking program is expecting. Those with full auto doppler correction should disable their RX auto correction and they will have to manually adjust their downlink frequency when an another station is not auto correcting or manually correcting his uplink frequency.
The biggest impact when you don't adjust or that you manually adjust your uplink frequency is that you can drift over another QSO. The ARRL Handbook is correct when they give the VO-52 example but they should give the explanation and this explanation is not easy to understand for a new satellite user.
In an ideal satellite world all the users should use auto doppler correction. In a less than ideal satellite world all the user should use uplink auto doppler correction and in the actual real time satellitte world be prepared for the worse... and be flexible...
There is also another chapter on the auto doppler correction when you will try to answer a CQ call but depending of your type of transceiver and type of doppler correctrion software you will have to experience your own ways just take my station as an example.
My FT-847 in CAT mode does not send any data back to the PC (First version of the FT-847) the transceiver can only received data from the PC and if i want to answer a CQ call i have to reenter the new uplink and downlink frequency of the calling station and try to tweaked them during the QSO it is a lot of work on a 10 minutes pass...
There is a lot a flavour in the doppler correction world but IMHO the uplink frequency should always be auto corrected and if it is not auto corrected the TX frequency should never be adjusted only if you drift on another QSO or if someone else is drifting on you. There no perfect solution aside of the full auto doppler correction.
I'm using full auto doppler correction when transponder activity is low as i always ended up stepping over a lot of station and be stepped on when there is a lot of traffic on a transponder. The worse case i saw was on AO-40 one fellow who was in full doppler correction ask the other station to move away as he move over the other QSO'S telling he's having priority over the manual corrected stations...
A suggestion is it possible to have a section on a transponder devoted only for those who are using auto tracking in voice mode? lets say the upper end section?
There is nothing perfect only imperfect solutions.
"-"
Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE
Joe,
I have used both manual tuning over the years and automated Doppler tuning since last year using SatPC. As Tim N3TL mentioned, I was on a recent Dxpedition working portable satellite from KH6 using an FT857D for transmit and an FT817 for receive. I used the automated tracking on the linear and FM satellites with complete success. This allowed me to concentrate on logging and manually tuning the antenna on my tripod during each pass. I am very happy with SatPC and it works like a charm as designed. I and many other users have had great support by the author.
What program are using? What radios are you using? Do your radios have CAT interfaces? I can help you with getting the settings properly set so you can make Doppler tracking work properly with minimal effort. I know there is a little bit of a leaning curve with SatPC, but once you have it up and running it works like a charm. I can attest to that having used it in the field in half duplex and full duplex mode during my DXpeditions. I usually just give the receive knob a small nudge once in a while to be on downlink frequency.
Let me and the group know if you would like some assistance to make it work for you. Collectively we can provide lots of feedback.
73, Adrian AA5UK
________________________________ From: "Gary "Joe" Mayfield" gary_mayfield@hotmail.com To: amsat-bb@amsat.org Sent: Mon, May 31, 2010 9:05:09 PM Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Tim,
Speak for yourself :-) In the 20+ years I have been a satellite operator, I have never gotten computer doppler control to work right on the linear birds. It works great on FM, but I always wind up fighting it on the linear birds. As soon as I tune the other guy in the computer moves me off frequency. It's so much easier to just listen and adjust on the fly.
Maybe there is some secret, but I have yet to be clued in... If someone wants to write a "Dummies Guide" for this I would be willing to be your test subject.
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Tim - N3TL Sent: Monday, May 31, 2010 8:42 PM To: APBIDDLE@mailaps.org; 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, John and all,
There is no question that computer-controlled Doppler tuning makes working the linear satellites easier. That being said, I am glad that my lack of a computer to dedicate to ham radio forced me to learn and use manual tuning by following the one true rule of always tuning the higher frequency.
These days, I often use SatPC 32 for computer control when I use my two FT-817 QRP rigs for the satellites. But last year, right after Field Day, the CAT plug on my FT-857D stopped working. Because of the choices I've made about my station setup (i.e., a totally portable station that I can set up and operate anywhere at any time), I need to use the 857 as a transmit radio in order to work the DX into Europe and Africa that I have on AO-7 Mode B. And without its higher power on 2 meters, I would not have gotten Hawaii into the log earlier this year on FO-29 from Adrian, AA5UK/KH6. Since the CAT plug died on the 857, I have been manually tuning on every pass during which I use that radio.
I really like being able to do it, even if I don't have to. I hope new satellite operators will take the time to at least develop the basic ability to effectively use manual tuning. But then - dinosaur that I am - I also wish more amateurs in general would at least learn Morse Code at slow speeds ... hihi.
And since we're on the topic ... has anyone else noticed that the latest edition of "The ARRL Satellite Handbook" uses VO-52 as the example for Doppler tuning - and that it suggests that newcomers who are manually tuning for Doppler park their transmit frequency on the UHF uplink and tune the VHF downlink (i.e., the exact opposite of the One True Rule)? That is really mystifying and disappointing.
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan P. Biddle Sent: Monday, May 31, 2010 6:07 PM To: 'John Belstner'; amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
John,
MacDoppler, SATPC32, Ham Radio Deluxe, and other programs all support what has been called the One True Rule. The usual name for the implementation is Full Doppler Tuning. You are doing it right. When everyone does this, it provides a very pleasant opportunity to talk instead of tune. It also keeps from drifting all over another QSO, though the transponders are seldom full these days.
However, that is not to say that people not using this are doing it wrong, exactly. There are still many rigs in use which do not have the capability for computer frequency control. In the old days, the rule was to tune the highest frequency, whether uplink or downlink, since this is where the Doppler shift is greatest. Take a look at KB5MU's original article and updates here:
http://www.amsat.org/amsat/features/one_true_rule.html
My suggestion is to use full tuning until you find that the other operator isn't. Then adapt, usually by turning off the updating for the lower frequency. It isn't worth getting doctrinaire about it. However, by using the One True Rule as the default, you set a good example and encourage the movement of other operators in this direction. As you will find, it is truly painful to do it the manual way after getting used to automagic tuning. As we move above 70 cms, full tuning truly becomes necessary.
Alan WA4SCA
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Belstner Sent: Monday, May 31, 2010 3:36 PM To: amsat-bb@amsat.org Subject: [amsat-bb] Doppler Tuning Convention Question
I know there is a lot of discussion on this subject in the AMSAT archives, but I've recently read a few posts to the BB that have me confused.
Just this weekend I got my Sat station on the air (FT-736R w/MacDoppler) and I noticed that the MacDoppler program I use adjusts both the TX and RX frequencies during the satellite pass. I'm assuming this is to keep my signal located in the same place in the transponder. The program seemed to work quite well. I was able to copy several QSO's on VO-52 and made a couple contacts as well.
One thing I noticed is that about half the QSO's I copied did not require any manual tuning on my part (MacDoppler adjusted the RX correctly) while the other half did. According to MacDoppler, those that did require manual tuning were moving around within the transponder passband.
I've read a few posts (one as recent as today) that suggested the convention is to keep the RX frequency fixed and manually adjusting the TX frequency while monitoring the downlink. Looking through the AMSAT archives this is the old convention prior to the popularity of tracking software and CAT control. So my question is, are there two conventions? or do I not have my software configured correctly?
Sorry for what might seem like a stupid question, but I'm a newbie to this facet of Ham Radio. BTW, I'm having a blast!
Cheers,
John Belstner w9en@arrl.net
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From: n3tl@bellsouth.net To: APBIDDLE@mailaps.org; jbelstner@yahoo.com; amsat-bb@amsat.org Date: Mon, 31 May 2010 21:42:09 -0400 Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
Actually, I've been running 2.4 ghz manually since AO-40, and really haven't had that much trouble. Just keep spinning the dial. Also, having an older rig (736r), I don't bother with computer control when on the linear birds. I do relax under full computer control for FM up through L-band, but there's still something satisfying about manual tuning.
Greg KO6TH
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Greg,
A good compromise, and I certainly understand the desire to remain in the loop. It allows the other operator to take advantage of greater automation or not, as suits them.
Alan WA4SCA
-----Original Message----- From: Greg D. [mailto:ko6th_greg@hotmail.com] Sent: Monday, May 31, 2010 11:37 PM To: n3tl@bellsouth.net; apbiddle@mailaps.org; jbelstner@yahoo.com; amsat-bb@amsat.org Subject: RE: [amsat-bb] Re: Doppler Tuning Convention Question
From: n3tl@bellsouth.net To: APBIDDLE@mailaps.org; jbelstner@yahoo.com; amsat-bb@amsat.org Date: Mon, 31 May 2010 21:42:09 -0400 Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for
having
no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
Actually, I've been running 2.4 ghz manually since AO-40, and really haven't had that much trouble. Just keep spinning the dial. Also, having an older rig (736r), I don't bother with computer control when on the linear birds. I do relax under full computer control for FM up through L-band, but there's still something satisfying about manual tuning.
Greg KO6TH
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Greg,
Thanks for this reply. It's nice to know that even the highest of currently-in-use satellite frequencies are do-able without computer aid. I'm pleased to hear that, and will rethink my position on things above 70 cm.
To Joe and Bruce - Here, I have noticed particular challenges with VO-52, whose Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up with. The Mode J satellites and AO-7 Mode B haven't really been too troublesome. At the end of the day, however, tuning manually remains a very viable option for any of us, in my opinion.
73 to all,
Tim - N3TL
________________________________ From: Greg D. ko6th_greg@hotmail.com To: n3tl@bellsouth.net; apbiddle@mailaps.org; jbelstner@yahoo.com; amsat-bb@amsat.org Sent: Tue, June 1, 2010 12:36:55 AM Subject: [amsat-bb] Re: Doppler Tuning Convention Question
From: n3tl@bellsouth.net To: APBIDDLE@mailaps.org; jbelstner@yahoo.com; amsat-bb@amsat.org Date: Mon, 31 May 2010 21:42:09 -0400 Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Alan, I have no doubt that you're right about the necessity for Doppler control above Mode B satellites. Having always preferred the KISS approach whenever possible, I suppose that's why I haven't been able to get myself very excited for L- and S-band opportunities. I definitely enjoy the benefits of computer control for Doppler. I just don't much care for having no choice in using it (or not) to effectively work a satellite.
73 to all,
Tim - N3TL
Actually, I've been running 2.4 ghz manually since AO-40, and really haven't had that much trouble. Just keep spinning the dial. Also, having an older rig (736r), I don't bother with computer control when on the linear birds. I do relax under full computer control for FM up through L-band, but there's still something satisfying about manual tuning.
Greg KO6TH
_________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. http://www.windowslive.com/campaign/thenewbusy?ocid=PID28326::T:WLMTAGL:ON:W... _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Folks I've been patiently silent reading this déjà vu annual discussion and I'm getting a brain crap.
- comments that tuning the highest frequency is the "One True Method" Yikes! Why is that? So you can leap frog down the pass band and eventually stomp all over a QSO where folks are tuning both TX and RX to maintain a single constant frequency at the satellite?
I've read the " Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up". Mid pass is when the sat is moving most tangentially to you at which point Doppler shift is nil.
I've read statements from many taking pride in their lack of use of current technology.
I've read that working tight SSB sats is easier than the wide band FM where the satellite is very forgiving of your sloppy tuning.
I've read advise to someone using an FT 736r that your shouldn't tune the RX and ignore the use of the NOR/REV feature, again so you can eventually stomp on other QSO's as you slide down the pass band.
Have I just been transported into a Bizarro World?
73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca
Hi Alan,
Your comments suggest that I'm the one in Bizarro World.
Regarding the One True Rule - I operate under the impression (which, I thought, has been backed by science) that regardless of the frequency pair, Doppler always will have a more pronounced effect (in relative terms, of course, based on the frequencies being used) on the higher of the two. In a perfect world, ever operator will be tuning for Doppler the same way. reality, of course, is that some people either can't use computer-aided Doppler tuning (my situation for the first several months that I worked the linear satellites) or they choose not to - as I still often do. And when I do, I will continue to compensate - most - for the frequency being most affected by Doppler, which is the higher frequency.
Regarding mid-pass - My experience suggests that, while your statement about mid-pass Doppler shift is accurate, it does not take into account that mid-pass occurs for only a moment in time during any orbit. My experience has been that the lower a satellite's orbit, the more significant Doppler movement will be. VO-52 is the prime example, in my opinion. And here, for me, the time just before and just after (say, 20-30 seconds on each side) mid-pass is when Doppler affects the uplink frequency the most. The computer and software I use often have not been able to adjust my radio's frequency as quickly as they need to in order to compensate for Doppler. Others may not have that problem with their computer-tuning system, but I believe the more-rapid Doppler effect is consistent for VO-52 regardless of how one is tuning. I'm confident (and, actually hope) that others will correct me if I'm wrong about the relative speed of Doppler correlating to the relative height of a satellite's orbit.
Regarding pride associated with the decision to not use current technology - Any measure of pride I take from knowing how to routinely tune for Doppler manually comes from the knowledge that circumstances and situations may arise when I will be asked to communicate effectively through the satellites without access to everything associated with current technology. My station is founded in that concept. I don't have an all-mode, full-duplex radio. I use two radios with a diplexer connecting them to one antenna. I don't have an az/el rotator; well, actually I do. It has three parts - shoulder, elbow and wrist. I don't have two very large, high-gain antennas. The only satellite antenna I own and use (other than some whips for the HTs) is the Elk dual-band log periodic. All of that being said, I am proud to say that I can use the gear I have to work any of the current fleet of single-channel-FM and linear-transponder satellites from anywhere - even without access to a computer or even to power. In that regard, Patrick - WD9EWK - has been an inspiration and mentor. His station is similar to mine.
I can't comment on your last two statements (about SSB vs. FM satellites and how to appropriate use a Yaesu FT-736r) because I didn't comment initially on either one. Personally, I find the FM satellites easier to work than the birds with linear transponders - but the latter are easier to make contacts on because they never attract nearly the number of operators on a single pass as the FM satellites. NONE of them are as difficult to work as I believed. They represent the most fun and satisfying operation I've ever done in amateur radio.
73 to all ... from the EM84 chunk of Bizarro World....
Tim - N3TL
________________________________ From: Alan ve4yz@hotmail.com To: amsat-bb@amsat.org Sent: Tue, June 1, 2010 9:31:36 AM Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Folks I've been patiently silent reading this déjà vu annual discussion and I'm getting a brain crap.
- comments that tuning the highest frequency is the "One True Method" Yikes! Why is that? So you can leap frog down the pass band and eventually stomp all over a QSO where folks are tuning both TX and RX to maintain a single constant frequency at the satellite?
I've read the " Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up". Mid pass is when the sat is moving most tangentially to you at which point Doppler shift is nil.
I've read statements from many taking pride in their lack of use of current technology.
I've read that working tight SSB sats is easier than the wide band FM where the satellite is very forgiving of your sloppy tuning.
I've read advise to someone using an FT 736r that your shouldn't tune the RX and ignore the use of the NOR/REV feature, again so you can eventually stomp on other QSO's as you slide down the pass band.
Have I just been transported into a Bizarro World?
73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Thanks to everyone that responded. For those that have been on the list for years this thread may be a dull rerun, but as a newbie, the information is useful.
From everyones responses, it appears that indeed there are currently two conventions:
1. Full Doppler CAT tuning 2. Manually tuning the higher frequency while keeping the lower fixed
I know that operators have been successfully using convention #2 for years so this is my lack of sat operating experience talking here, but just looking at the math it seems that it would be difficult for two stations with different velocity vectors to the satellite to communicate without at least one of them adjusting both TX and RX. I need to try this for myself I guess.
One thing I did notice is that when operating Full Doppler CAT tuning I was only able to successfully track other operators who were doing the same.
Cheers,
73, John W9EN DM13le W9EN@AMSAT.ORG
John,
I meant to mention a nice page discussing Doppler shift. It explains many of the questions/comments/rants brought up about Doppler shifts and corrections:
http://www.qsl.net/vk3jed/doppler.html
It gives a few graphic illustrations of how Doppler shift varies depending on the pass, and why it can be radically different for different stations in the QSO. As you observed, Full Doppler Tuning, FDT, works for everybody, everytime. I will add that any can play. Anything else is just an approximation. We have 40 years of experience showing that approximation is usuable, but we have long been able to do better.
Thanks for motivating me to get back to an article on exactly this subject I have been meaning to finish.
73s,
Alan WA4SCA
At 04:45 AM 6/2/2010, Alan P. Biddle wrote:
John,
I meant to mention a nice page discussing Doppler shift. It explains many of the questions/comments/rants brought up about Doppler shifts and corrections:
Please use the official version
http://vkradio.com/doppler.html :)
You'll find the speed better. :)
It gives a few graphic illustrations of how Doppler shift varies depending on the pass, and why it can be radically different for different stations in the QSO. As you observed, Full Doppler Tuning, FDT, works for everybody, everytime. I will add that any can play. Anything else is just an approximation. We have 40 years of experience showing that approximation is usuable, but we have long been able to do better.
I agree, Full Dopller Tuning is the best way to go, if you have the gear. I'm looking forward to giving it a go, when I get my satellite antennas up. The radio and CAT interface are in position.
73 de VK3JED / VK3IRL http://vkradio.com
In a perfect world, everyone would be using full doppler control via computer. As we can see from this discussion, it's not a perfect world. During the time that I had the equipment to operate the linear birds I found hooking up in a QSO with another station who was using full doppler tuning by computer also was quite an enjoyable experience. Even "reading the mail" while two other gents were in contact on full doppler was fun. Not so if I came upon a station who was using manual tuning while I was trying to let my computer do the work. I had to chase him all over the passband and often lost stations completely that way. I didn't fare much better with manual tuning. I guess I never really learned it like some of the "old hands" have. When I can finally afford the V/U unit for my new Flex and get back on linear birds it would be my hope that everyone who was in a base station setup would be using full doppler control via computer. It baffles me why anyone wouldn't, it makes life so much easier. I do understand why portable stations like Tim would not be using full doppler and I have no problem with that. I guess I just need to learn how to manually tune in that situation. 73, Michael W4HIJ On 6/1/2010 12:14 PM, John Belstner wrote:
Thanks to everyone that responded. For those that have been on the list for years this thread may be a dull rerun, but as a newbie, the information is useful.
From everyones responses, it appears that indeed there are currently two conventions:
- Full Doppler CAT tuning
- Manually tuning the higher frequency while keeping the lower fixed
I know that operators have been successfully using convention #2 for years so this is my lack of sat operating experience talking here, but just looking at the math it seems that it would be difficult for two stations with different velocity vectors to the satellite to communicate without at least one of them adjusting both TX and RX. I need to try this for myself I guess.
One thing I did notice is that when operating Full Doppler CAT tuning I was only able to successfully track other operators who were doing the same.
Cheers,
73, John W9EN DM13le W9EN@AMSAT.ORG
At 05:53 AM 6/2/2010, Michael Tondee wrote:
was fun. Not so if I came upon a station who was using manual tuning while I was trying to let my computer do the work. I had to chase him all over the passband and often lost stations completely that way. I didn't fare much better with manual tuning. I guess I never really learned it like some of the "old hands" have.
I have had quite a bit of success with manual tuning on the SSB birds. It does require a lot of attention, especially on V/U and U/V. On mode A, it's fairly straightforward, though adjusting the uplink on a radio that doesn't allow tuning on transmit is tricky! One has to break their over into short segments of a few seconds long and make the uplink adjustment in steps. :)
On V/U, I was using an FT-847 at a hamfest, which was easier, provided I focused on keeping up with the Doppler. :D
When I can finally afford the V/U unit for my new Flex and get back on linear birds it would be my hope that everyone who was in a base station setup would be using full doppler control via computer. It baffles me why anyone wouldn't, it makes life so much easier.
In my past, it was simply because I didn't have the right radio(s). Now I have an FT-736R, and the first accessory I bought for it was a CAT cable! :) I can even dedicate a computer to the job.
I do understand why portable stations like Tim would not be using full doppler and I have no problem with that. I guess I just need to learn how to manually tune in that situation.
Yep, it can be fiddly, but rewarding.
73, Michael W4HIJ On 6/1/2010 12:14 PM, John Belstner wrote:
Thanks to everyone that responded. For those that have been on the list for years this thread may be
a dull rerun, but as a newbie, the information is useful.
From everyones responses, it appears that indeed there are
currently two conventions:
- Full Doppler CAT tuning
- Manually tuning the higher frequency while keeping the lower fixed
I know that operators have been successfully using convention #2
for years so this is my lack of sat operating experience talking here, but just looking at the math it seems that it would be difficult for two stations with different velocity vectors to the satellite to communicate without at least one of them adjusting both TX and RX. I need to try this for myself I guess.
One thing I did notice is that when operating Full Doppler CAT
tuning I was only able to successfully track other operators who were doing the same.
Cheers,
73, John W9EN DM13le W9EN@AMSAT.ORG
Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73 de VK3JED / VK3IRL http://vkradio.com
Date: Wed, 2 Jun 2010 07:36:40 +1000 To: mat_62@netcommander.com; amsat-bb@amsat.org From: vk3jed@gmail.com Subject: [amsat-bb] Re: Doppler Tuning Convention Question (summary)
At 05:53 AM 6/2/2010, Michael Tondee wrote:
When I can finally afford the V/U unit for my new Flex and get back on linear birds it would be my hope that everyone who was in a base station setup would be using full doppler control via computer. It baffles me why anyone wouldn't, it makes life so much easier.
In my past, it was simply because I didn't have the right radio(s). Now I have an FT-736R, and the first accessory I bought for it was a CAT cable! :) I can even dedicate a computer to the job.
One problem with the Yaesu 736R is that when the rig is under computer control you can't grab the tuning knob and hunt around the passband for someone to talk to. "Tuning" directed by computer is agonizingly slow and tedious, taking about a second per change, so that's out. And since the rig's frequency cannot be read by the computer, you can't hunt manually and then lock things in on the computer. (I suppose I could re-write my CAT client to allow me to visually read the frequency off the display and type it in, but that would be tedious too...)
So, for me, SSB is full manual. FM is full computer. (and CW is wishful thinking) Sometimes I'll use the computer to get my manual tuning started, picking mid-passband to get the VFOs close. Then I disable the computer, send a few dits to verify, flip to REV to lock the VFOs, and go manual from there. If you run full manual often enough, it becomes second nature. I used to be able to find myself on RS-10 in just a few seconds, anywhere in the passband. But that was a REAL "EasySat".
Greg KO6TH
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At 01:18 PM 6/2/2010, Greg D. wrote:
One problem with the Yaesu 736R is that when the rig is under computer control you can't grab the tuning knob and hunt around the passband for someone to talk to. "Tuning" directed by computer is agonizingly slow and tedious, taking about a second per change, so that's out. And since the rig's frequency cannot be read by the computer, you can't hunt manually and then lock things in on the computer. (I suppose I could re-write my CAT client to allow me to visually read the frequency off the display and type it in, but that would be tedious too...)
That does make things a pain. It's a pity that the radio can't talk back to the computer, which would have been a nice addition.
go manual from there. If you run full manual often enough, it becomes second nature. I used to be able to find myself on RS-10 in just a few seconds, anywhere in the passband. But that was a REAL "EasySat".
Well, I had no problems flying the RS birds manually, and I have done the Fujis as well.
73 de VK3JED / VK3IRL http://vkradio.com
That does make things a pain. It's a pity that the radio can't talk back to the computer, which would have been a nice addition.
The true pity is that the rig IS physically capable of talking to the computer, but the only thing it knows how to say is what the status of the Squelch is (open/closed), and what the S-meter is reading. It should be a trivial matter of software to report other things, but apparently the only use the CAT designers considered was remote (computer-driven) scanning and monitoring.
{sigh}
Greg KO6TH
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Just a quick comment on Doppler effects. Doppler offset from the resting frequency is observable only on the radial velocity component of the satellite and that is usually most significant at AOS or LOS. BUT what the operator is usually responding is to the rate of change of Doppler and not the absolute value of the frequency offset. Doppler rate change may occur more at mid-pass than elsewhere.
Regarding the "one true rule" that is generally only accomplished by software tuning both uplink and downlink simultaneously, the manual method of tuning the higher frequency will never mesh exactly with the other mode. FM should be more forgiving of Doppler shifts due to the 15-KHz bandwidth of the signal. Some radios even have AFC to maintain change in frequency in the FM mode.
Higher frequencies show more Doppler and the rate of change will also be proportional. Thus the difficulty manual tuning mode LS for Leos.
73, Ed - KL7uW
At 06:49 AM 6/1/2010, Tim - N3TL wrote:
Hi Alan,
Your comments suggest that I'm the one in Bizarro World.
Regarding the One True Rule - I operate under the impression (which, I thought, has been backed by science) that regardless of the frequency pair, Doppler always will have a more pronounced effect (in relative terms, of course, based on the frequencies being used) on the higher of the two. In a perfect world, ever operator will be tuning for Doppler the same way. reality, of course, is that some people either can't use computer-aided Doppler tuning (my situation for the first several months that I worked the linear satellites) or they choose not to - as I still often do. And when I do, I will continue to compensate - most - for the frequency being most affected by Doppler, which is the higher frequency.
Regarding mid-pass - My experience suggests that, while your statement about mid-pass Doppler shift is accurate, it does not take into account that mid-pass occurs for only a moment in time during any orbit. My experience has been that the lower a satellite's orbit, the more significant Doppler movement will be. VO-52 is the prime example, in my opinion. And here, for me, the time just before and just after (say, 20-30 seconds on each side) mid-pass is when Doppler affects the uplink frequency the most. The computer and software I use often have not been able to adjust my radio's frequency as quickly as they need to in order to compensate for Doppler. Others may not have that problem with their computer-tuning system, but I believe the more-rapid Doppler effect is consistent for VO-52 regardless of how one is tuning. I'm confident (and, actually hope) that others will correct me if I'm wrong about the relative speed of Doppler correlating to the relative height of a satellite's orbit.
Regarding pride associated with the decision to not use current technology - Any measure of pride I take from knowing how to routinely tune for Doppler manually comes from the knowledge that circumstances and situations may arise when I will be asked to communicate effectively through the satellites without access to everything associated with current technology. My station is founded in that concept. I don't have an all-mode, full-duplex radio. I use two radios with a diplexer connecting them to one antenna. I don't have an az/el rotator; well, actually I do. It has three parts - shoulder, elbow and wrist. I don't have two very large, high-gain antennas. The only satellite antenna I own and use (other than some whips for the HTs) is the Elk dual-band log periodic. All of that being said, I am proud to say that I can use the gear I have to work any of the current fleet of single-channel-FM and linear-transponder satellites from anywhere - even without access to a computer or even to power. In that regard, Patrick - WD9EWK - has been an inspiration and mentor. His station is similar to mine.
I can't comment on your last two statements (about SSB vs. FM satellites and how to appropriate use a Yaesu FT-736r) because I didn't comment initially on either one. Personally, I find the FM satellites easier to work than the birds with linear transponders - but the latter are easier to make contacts on because they never attract nearly the number of operators on a single pass as the FM satellites. NONE of them are as difficult to work as I believed. They represent the most fun and satisfying operation I've ever done in amateur radio.
73 to all ... from the EM84 chunk of Bizarro World....
Tim - N3TL
From: Alan ve4yz@hotmail.com To: amsat-bb@amsat.org Sent: Tue, June 1, 2010 9:31:36 AM Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Folks I've been patiently silent reading this déjà vu annual discussion and I'm getting a brain crap.
- comments that tuning the highest frequency is the "One True Method"
Yikes! Why is that? So you can leap frog down the pass band and eventually stomp all over a QSO where folks are tuning both TX and RX to maintain a single constant frequency at the satellite?
I've read the " Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up". Mid pass is when the sat is moving most tangentially to you at which point Doppler shift is nil.
I've read statements from many taking pride in their lack of use of current technology.
I've read that working tight SSB sats is easier than the wide band FM where the satellite is very forgiving of your sloppy tuning.
I've read advise to someone using an FT 736r that your shouldn't tune the RX and ignore the use of the NOR/REV feature, again so you can eventually stomp on other QSO's as you slide down the pass band.
Have I just been transported into a Bizarro World?
73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubususa@hotmail.com ======================================
At 11:31 PM 6/1/2010, Alan wrote:
I've read the " Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up". Mid pass is when the sat is moving most tangentially to you at which point Doppler shift is nil.
The rate of change of Doppler shift is at a maximum at this point, which means you're moving the VFO knob fastest. It's like when you hear a passing car, the change of pitch happens as the car is passing you.
Yes, the amount of Doppler shift might be zero then the satellite is tangential, but the rate of change (in Hz/second) is maximum.
73 de VK3JED / VK3IRL http://vkradio.com
The one TRUE method is do whatever it takes to make the QSO!
In reality I almost always wind up tuning both up and down links. I make sure most of the adjusting is on the higher frequency.
I can't say I have ever slid into another QSO, but even if I do, it is just an opportunity to speak with more friends I haven't met yet! I am usually very hard pressed to find more than one or two QSOs in the passband anyway.
As I mentioned before I have found computer tuning to work just fine on the FM birds (no slop involved), but always find myself fighting against the computer aided linear tuning. I tune the station in perfectly and then the computer moves me off frequency. I tune the station in again and the computer moves me off frequency again. I turn the computer tuning off and make the QSO.
I would be game for some pointers as I would like to at least claim I have made this work once.
73, Joe kk0sd
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Alan Sent: Tuesday, June 01, 2010 8:32 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Doppler Tuning Convention Question
Folks I've been patiently silent reading this déjà vu annual discussion and I'm getting a brain crap.
- comments that tuning the highest frequency is the "One True Method" Yikes! Why is that? So you can leap frog down the pass band and eventually stomp all over a QSO where folks are tuning both TX and RX to maintain a single constant frequency at the satellite?
I've read the " Doppler tends to move more quickly near mid-pass than the computer and software routinely seem able to keep up". Mid pass is when the sat is moving most tangentially to you at which point Doppler shift is nil.
I've read statements from many taking pride in their lack of use of current technology.
I've read that working tight SSB sats is easier than the wide band FM where the satellite is very forgiving of your sloppy tuning.
I've read advise to someone using an FT 736r that your shouldn't tune the RX and ignore the use of the NOR/REV feature, again so you can eventually stomp on other QSO's as you slide down the pass band.
Have I just been transported into a Bizarro World?
73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (13)
-
Adrian Engele -
Alan -
Alan P. Biddle -
Art McBride -
Bruce -
Edward R Cole -
Gary "Joe" Mayfield -
Greg D. -
John Belstner -
Luc Leblanc -
Michael Tondee -
Tim - N3TL -
Tony Langdon