Listening on USB when operating CW
I assume many home station satellite operators utilize some kind of full-duplex radio or combination of two radios for CW on the current satellites.
Lately, as I have been listening a lot more with my FUNcube Dongle Pro+, I have observed many CW stations drifting across the satellites' passband. I realize this is not a new phenomenon. I would assume these drifting stations are NOT using any type of computer Doppler correction. If they were using computer control, I would assume their CW would stay on the same place in the transponder's passband. It is visually apparent when the stations manually make larger frequency movements because of the curve displayed on my SDR application's waterfall display.
Many times I have been engaged in a QSO only to have someone CQ'ing on CW drift across my existing QSO. Anyone who operates satellites has probably had this happen to them many times. Sometimes myself or others in QSO may try to tell the CW operator "Hello - QSO in progress" but it is apparent they are not hearing us.
My question is, does it make sense for people using CW on the satellites to have their receiver set to USB? Do some operators do this? If listening on a VFO with USB and had your transmit VFO set to CW, would this help make it easier for CW ops to know when they have drifted into an existing voice QSO?
73 Clayton W5PFG
Correct me if I'm wrong, but doesn't automatic doppler corrections dynamically change your frequency to compensate for doppler? Would this mean anyone engaging in doppler correction are actually drifting into a stable frequency?
73 Peter ve7ngp
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Clayton Coleman Sent: February 7, 2014 08:43 To: AMSAT-BB Subject: [amsat-bb] Listening on USB when operating CW
I assume many home station satellite operators utilize some kind of full-duplex radio or combination of two radios for CW on the current satellites.
Lately, as I have been listening a lot more with my FUNcube Dongle Pro+, I have observed many CW stations drifting across the satellites' passband. I realize this is not a new phenomenon. I would assume these drifting stations are NOT using any type of computer Doppler correction. If they were using computer control, I would assume their CW would stay on the same place in the transponder's passband. It is visually apparent when the stations manually make larger frequency movements because of the curve displayed on my SDR application's waterfall display.
Many times I have been engaged in a QSO only to have someone CQ'ing on CW drift across my existing QSO. Anyone who operates satellites has probably had this happen to them many times. Sometimes myself or others in QSO may try to tell the CW operator "Hello - QSO in progress" but it is apparent they are not hearing us.
My question is, does it make sense for people using CW on the satellites to have their receiver set to USB? Do some operators do this? If listening on a VFO with USB and had your transmit VFO set to CW, would this help make it easier for CW ops to know when they have drifted into an existing voice QSO?
73 Clayton W5PFG _______________________________________________ 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 2/7/2014 11:18 AM, Ng, Peter wrote:
Correct me if I'm wrong, but doesn't automatic doppler corrections dynamically change your frequency to compensate for doppler? Would this mean anyone engaging in doppler correction are actually drifting into a stable frequency?
by "stable" do you mean a freq already being used?
John, W0JAB
Yes, the frequency in use by the CW station that is not adjusting for doppler will appear to be moving for stations that are adjusting for doppler....right?
Peter ve7ngp
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Becker Sent: February 7, 2014 09:27 To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Listening on USB when operating CW
On 2/7/2014 11:18 AM, Ng, Peter wrote:
Correct me if I'm wrong, but doesn't automatic doppler corrections dynamically change your frequency to compensate for doppler? Would this mean anyone engaging in doppler correction are actually drifting into a stable frequency?
by "stable" do you mean a freq already being used?
John, W0JAB
_______________________________________________ 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
Peter,
That is correct and what I have attempted to describe. A station not adjusting properly for Doppler shift will appear to "move" across the passband into stations who are making corrections. (voice or CW)
There are several categories for correction, as I see it by order of occurrence...(and there may be more)
1 - People who use "full" Doppler correction via software, adjusting both TX and RX to stay on the satellite's frequency.
2 - People who use "half" Doppler correction by tuning the higher of two frequencies. This is common for people who are portable or want the simplest method of staying on another station. In the mode, you will move slightly. I do this often in the field. It's not perfect.
3 - People who use "TX only" correction. I see this often and I believe it's an incorrect practice to always tune TX because sometimes that means on mode J you'll likely move across QSO's in progress.
4 - Probably the least common I observe, people who use "full" Doppler correction manually. I believe it is a little more difficult to do this on fast moving LEO's, especially on CW.
My original email was trying to discover whether or not listening on USB while transmitting on CW might make it easier for "CW drifters" to know they are part of a problem. Occasionally when this problem occurs with USB voice, the perpetrating stations are not able to hear well enough to know they are causing a problem.
73 Clayton W5PFG
On Fri, Feb 7, 2014 at 11:33 AM, Ng, Peter Peter.Ng@bccdc.ca wrote:
Yes, the frequency in use by the CW station that is not adjusting for doppler will appear to be moving for stations that are adjusting for doppler....right?
Peter ve7ngp
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of John Becker Sent: February 7, 2014 09:27 To: amsat-bb@amsat.org Subject: [amsat-bb] Re: Listening on USB when operating CW
On 2/7/2014 11:18 AM, Ng, Peter wrote:
Correct me if I'm wrong, but doesn't automatic doppler corrections dynamically change your frequency to compensate for doppler? Would this mean anyone engaging in doppler correction are actually drifting into a stable frequency?
by "stable" do you mean a freq already being used?
John, W0JAB
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
Thanks Clayton, that's good to know....
73 Peter ve7ngp
-----Original Message----- Peter,
That is correct and what I have attempted to describe. A station not adjusting properly for Doppler shift will appear to "move" across the passband into stations who are making corrections. (voice or CW)
There are several categories for correction, as I see it by order of occurrence...(and there may be more)
1 - People who use "full" Doppler correction via software, adjusting both TX and RX to stay on the satellite's frequency.
2 - People who use "half" Doppler correction by tuning the higher of two frequencies. This is common for people who are portable or want the simplest method of staying on another station. In the mode, you will move slightly. I do this often in the field. It's not perfect.
3 - People who use "TX only" correction. I see this often and I believe it's an incorrect practice to always tune TX because sometimes that means on mode J you'll likely move across QSO's in progress.
4 - Probably the least common I observe, people who use "full" Doppler correction manually. I believe it is a little more difficult to do this on fast moving LEO's, especially on CW.
My original email was trying to discover whether or not listening on USB while transmitting on CW might make it easier for "CW drifters" to know they are part of a problem. Occasionally when this problem occurs with USB voice, the perpetrating stations are not able to hear well enough to know they are causing a problem.
73 Clayton W5PFG
I am not a constant user of the sats, but I notice this with both some CW and SSB transmissions.
Some sats just have drift.
It is still fun.
God Bless
R W4BUE
----- Original Message ----- From: "Clayton Coleman" kayakfishtx@gmail.com To: "AMSAT-BB" amsat-bb@amsat.org Sent: Friday, February 07, 2014 11:42 AM Subject: [amsat-bb] Listening on USB when operating CW
I assume many home station satellite operators utilize some kind of full-duplex radio or combination of two radios for CW on the current satellites.
Lately, as I have been listening a lot more with my FUNcube Dongle Pro+, I have observed many CW stations drifting across the satellites' passband. I realize this is not a new phenomenon. I would assume these drifting stations are NOT using any type of computer Doppler correction. If they were using computer control, I would assume their CW would stay on the same place in the transponder's passband. It is visually apparent when the stations manually make larger frequency movements because of the curve displayed on my SDR application's waterfall display.
Many times I have been engaged in a QSO only to have someone CQ'ing on CW drift across my existing QSO. Anyone who operates satellites has probably had this happen to them many times. Sometimes myself or others in QSO may try to tell the CW operator "Hello - QSO in progress" but it is apparent they are not hearing us.
My question is, does it make sense for people using CW on the satellites to have their receiver set to USB? Do some operators do this? If listening on a VFO with USB and had your transmit VFO set to CW, would this help make it easier for CW ops to know when they have drifted into an existing voice QSO?
73 Clayton W5PFG _______________________________________________ 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
Clayton,
Lately, as I have been listening a lot more with my FUNcube Dongle
Pro+, I have observed many CW stations drifting across the satellites' passband. I realize this is not a new phenomenon. I would assume these drifting stations are NOT using any type of computer Doppler correction. If they were using computer control, I would assume their CW would stay on the same place in the transponder's passband. It is visually apparent when the stations manually make larger frequency movements because of the curve displayed on my SDR application's waterfall display.
You're basically correct.
Stations using full computer control like what you get in SatPC32 will be able to keep their frequencies steady at the satellite, but there would still be some drift in what you observe on your SDR software's waterfall display. I also see this when I'm working those stations with my portable two-radio setup, where I'm having to make minor adjustments on both my uplink and downlink frequencies to keep up with the other station. For the mode B satellites where the operators are only adjusting the higher of the two frequencies (uplink), it might be easier to keep the downlink frequency at your receiver from drifting so much. There would be some drift at the satellite, but not so much on your waterfall display.
My question is, does it make sense for people using CW on the satellites to have their receiver set to USB? Do some operators do this? If listening on a VFO with USB and had your transmit VFO set to CW, would this help make it easier for CW ops to know when they have drifted into an existing voice QSO?
For the few times I have worked CW via satellite, I always set my receiver to USB. Without computer control, I would have to be adjusting my receive VFO all the time to keep the CW signal in my receiver's CW passband if it drifted. My ear can do an OK job of dealing with the drifting signal (changing pitch of the CW) when the receiver is in USB. When I use USB, I also avoid using any narrow receive filtering.
For the FUNcube Dongle Pro+ and HDSDR, I only use USB on these satellites. I may widen the audio passband HDSDR has for USB, but I don't bother putting it into CW when copying CW signals.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/
participants (5)
-
Clayton Coleman -
John Becker -
Ng, Peter -
Patrick STODDARD (WD9EWK/VA7EWK) -
Rich/wa4bue