hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to getting it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests.
If I understand your wiring, I think you have it correct.
Is this what you are trying to do? http://www.amsat.org/amsat-new/articles/Mode-J/
Note that for mode-B satellites where you are transmitting on 70cm and receiving on 2m, this won't work. In my experience, the extra filtering is also not needed there.
Good luck,
Greg KO6TH
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to getti! ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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
I am not sure that the filtering from the small duplexer with the Arrow is significant enough compared with the injection loss that it will produce.
I would try it first plumbed first directly into each radio. In this case the biggest issue will front end overload of the rx portable, I have not had problems when I tried it using FT817 and a Yesau handheld.
Dave WB7DRU Minnesota
Sent from my android device.
-----Original Message----- From: Greg D ko6th.greg@gmail.com To: Robert Coppock robertinorbit@webtv.net Cc: amsat-bb@amsat.org Sent: Sat, 02 Jun 2012 12:07 PM Subject: [amsat-bb] Re: full duplex w/ 2 HT's
If I understand your wiring, I think you have it correct.
Is this what you are trying to do? http://www.amsat.org/amsat-new/articles/Mode-J/
Note that for mode-B satellites where you are transmitting on 70cm and receiving on 2m, this won't work. In my experience, the extra filtering is also not needed there.
Good luck,
Greg KO6TH
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to get!
ti!
ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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
Well just for your information, I run a FT-7900 & FT-2900 right next to each other to a 10 elem Diamond 70cm and a 5 elem Diamond 2m both pretty close to each other and have never had a single problem.
Considering you are transmitting on 145.850 and receiving on 436.795... Hello, a world apart there and you are only using 5 watts. You will not have a problem and you will not even need a duplexer with the two hand helds.
Two radios, Two antennas, Two pieces of coax. True Full Duplex.... :)
Kevin KF7MYK
Date: Sat, 2 Jun 2012 14:53:27 -0500 From: wb7dru@usfamily.net To: ko6th.greg@gmail.com; robertinorbit@webtv.net CC: amsat-bb@amsat.org Subject: [amsat-bb] Re: full duplex w/ 2 HT's
I am not sure that the filtering from the small duplexer with the Arrow is significant enough compared with the injection loss that it will produce.
I would try it first plumbed first directly into each radio. In this case the biggest issue will front end overload of the rx portable, I have not had problems when I tried it using FT817 and a Yesau handheld.
Dave WB7DRU Minnesota
Sent from my android device.
-----Original Message----- From: Greg D ko6th.greg@gmail.com To: Robert Coppock robertinorbit@webtv.net Cc: amsat-bb@amsat.org Sent: Sat, 02 Jun 2012 12:07 PM Subject: [amsat-bb] Re: full duplex w/ 2 HT's
If I understand your wiring, I think you have it correct.
Is this what you are trying to do? http://www.amsat.org/amsat-new/articles/Mode-J/
Note that for mode-B satellites where you are transmitting on 70cm and receiving on 2m, this won't work. In my experience, the extra filtering is also not needed there.
Good luck,
Greg KO6TH
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to get!
ti!
ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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
On 02/06/12 17:33, Robert Coppock wrote:
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to getti! ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests.
Duplexers are for the same band, diplexers are for splitting bands. So, you want a diplexer for this. HB9ABX did a nice design but apparently doesn't want to give it out any more. I'm sure a quick Google will reveal the sickening truth that you cannot hide from the Internet.
Robert:
I have used a duplexer on the UHF side of my satellite ops for several years. I find that some radios have more of a desense problem than others. Here is a link to my website where I briefly talk about what I do on portable ops and using what is referred to as a Mode J filter - http://www.ka4kyi.com/satellite_gear/misc_equipment/
Ron Nutter KA4KYI AMSAT Area Coordinator for Missouri
On 6/2/12 11:33 AM, Robert Coppock wrote:
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to getti! ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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 .
So, all the on-line information seems to point to this solution - putting a diplexer (filter) on the 70cm side to tap off and absorb the incoming 2m signal. Isn't there also a design where one puts a filter on the 2m side, to tap off and absorb the 70 cm (3rd harmonic of 2m) signal?
I would think that any (reasonable) 70cm receiver would have enough rejection for a signal so far out of band, but the in-band 3rd harmonic can only be taken care of at its source. At least, I think that's the logic.
Is there anything worthy about the other design, or is the most common problem that our HTs can't possibly deal with a strong 2m signal on the 70cm side because of their "DC to Daylight" receivers?
I've been on the mode-J birds without much of a problem with this sort of desense, though I did have a lot of trouble on AO-40 with reflected RF when aiming through a big oak tree behind the house. The 70cm uplink was interfering with the 13cm downlink, and I was pretty sure at the time that it was a 3rd harmonic sort of problem.
Just curious,
Greg KO6TH
Ronald Nutter wrote:
Robert:
I have used a duplexer on the UHF side of my satellite ops for several years. I find that some radios have more of a desense problem than others. Here is a link to my website where I briefly talk about what I do on portable ops and using what is referred to as a Mode J filter - http://www.ka4kyi.com/satellite_gear/misc_equipment/
Ron Nutter KA4KYI AMSAT Area Coordinator for Missouri
On 6/2/12 11:33 AM, Robert Coppock wrote:
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to get!
ti!
ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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
Usually the diplexer as a filter is only needed to keep the 2m tx from overloading a 70cm preamp. For a two radio setup with no preamp, it usually isn't needed at all.
73, Drew KO4MA
Sent from my iPhone
On Jun 3, 2012, at 10:45 PM, Greg D ko6th.greg@gmail.com wrote:
So, all the on-line information seems to point to this solution - putting a diplexer (filter) on the 70cm side to tap off and absorb the incoming 2m signal. Isn't there also a design where one puts a filter on the 2m side, to tap off and absorb the 70 cm (3rd harmonic of 2m) signal?
I would think that any (reasonable) 70cm receiver would have enough rejection for a signal so far out of band, but the in-band 3rd harmonic can only be taken care of at its source. At least, I think that's the logic.
Is there anything worthy about the other design, or is the most common problem that our HTs can't possibly deal with a strong 2m signal on the 70cm side because of their "DC to Daylight" receivers?
I've been on the mode-J birds without much of a problem with this sort of desense, though I did have a lot of trouble on AO-40 with reflected RF when aiming through a big oak tree behind the house. The 70cm uplink was interfering with the 13cm downlink, and I was pretty sure at the time that it was a 3rd harmonic sort of problem.
Just curious,
Greg KO6TH
Ronald Nutter wrote:
Robert:
I have used a duplexer on the UHF side of my satellite ops for several years. I find that some radios have more of a desense problem than others. Here is a link to my website where I briefly talk about what I do on portable ops and using what is referred to as a Mode J filter - http://www.ka4kyi.com/satellite_gear/misc_equipment/
Ron Nutter KA4KYI AMSAT Area Coordinator for Missouri
On 6/2/12 11:33 AM, Robert Coppock wrote:
hola, i am trying to determine the best way to work full duplex on the birds with 2 HT's or radios. i cannot find any info so far on the web. my concern is to keep the transmit power out of the receive radio, i guess basically the difference between a diplexer and duplexer. since i am efficient (lazy) i thought i would just look for suggestions here while i am checking google also. what do i need, di/du/ plexer, and what is the correct wiring scheme ? i will be using the arrow antenna without the built in duplexer, from the 2 feeds (vhf/uhf) and 2 HT's for now. my picture of it so far, is to wire the vhf radio direct to the vhf feed port on the arrow, and have the uhf port on the arrow come into a duplexer, with the duplexer uhf port going to the uhf radio, and the duplexer vhf port terminated into a 50 ohm dummy load. also, any suggestions of specific duplexers would be appreciated. i think i started on this project a few years ago, but never got around to get!
ti!
ng it all together. grazie mille, Robert k f 0 g cn81 in the woodwork, literally, shasta/klamath national forests. _______________________________________________ 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
participants (7)
-
Andrew Glasbrenner -
Gordon JC Pearce -
Greg D -
Kevin Deane -
Robert Coppock -
Ronald Nutter -
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