Re: [amsat-bb] DopplerPSK - No 1 kHz-autotracking radio tuning
Question. All FM-only rigs of course only do 5 KHz steps anyway. Are we finding that multi-mode rigs when placed in FM mode can actually step smaller under CAT control?
If so, then we must point that out to users, since it will not work for PSK31 even in FM.
Thanks for the reminder. If rigs do that, then I will add this to the PSAT web page. The advice to not use auto-radio tuning except for 5 KHz steps on the downlink. IE, not smaller steps.
Bob, WB4APR
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of aflowers--- via AMSAT-BB Sent: Wednesday, June 12, 2019 10:58 PM To: [email protected]; Scott [email protected] Subject: Re: [amsat-bb] DopplerPSK
Scott, Roy, Umesh, et al; Part of the problem with PSK31 is that it required the adjustment for changes in Doppler shift to be to be phase-continuous. I think the Doppler rate (delta-Doppler shift) at even 10m is too fast for most radios--what you often get with CAT control, even if you can update while transmitting, is PSK31 that jumps more than 31Hz per update, and that totally destroys the phase continuity required to tell a '1' from '0'. This was the "fun" problem that spurred me to take a swing at it over a summer vacation. When DopplerPSK applies "anti-doppler" on the transmitted signal, it does so at the baseband audio level. This works fine for 3Khz passbands on a 10m uplink, but if you want to do it with SSB transponders and VHF and UHF you'll need an SDR where you aren't limited by an IF filter. The same algorithm in DopplerPSK could be used on a complex signal in the SDR architecture, and it could work equally on TX and RX in the processing chain. To the accuracy of the orbital elements everyone uses, if everyone corrects their uplink and downlink properly there is no perceived frequency drift by anyone using the satellite. Just what you need for a GHz-range LEO with a narrow-band transponder, eh? Since the downlink of NO-84 is FM there is no Doppler shift in the baseband audio of the downlink--you hear what the satellite hears. If we get a mode-K satellite it might be worthwhile to do a baseband demodulator in a soundcard since the total change in Doppler shift will be small enough to fit in a conventional HF radio's IF passband in both directions. If the antiquated hosting site doesn't come back I'll get off my duff and find a "proper" place for it. It's nice to see people playing around with it. (Thanks for bridging the gap in the meantime, Peter.) Andy K0SM/2
On Wednesday, June 12, 2019, 9:24:12 PM EDT, Scott via AMSAT-BB [email protected] wrote:
While it might certainly be possible to put together a solution that would compensate your uplink so that its corresponding downlink through the transponder holds stationary on a single spot on the downlink audio spectrum, there are two reasons (at least) that I can think of to not go to that trouble:
#1, the DopplerPSK app takes care of it perfectly already. The work has been done.
#2, if memory serves, some radios do not respond to CAT frequency adjustments when transmitting. In this mode, your uplink radio is transmitting non-stop for the entire ~10 minute pass. If you have a hardware/software setup that can only change RF frequency when in receive mode, that will never happen during an NO-84 pass.
Lastly, like much satellite work, the uplink and downlink are two completely separate discussions in this mode. While the 10m uplink works extremely well with the DopplerPSK software and the HF radio of your choice, receiving & demodulating the PSK31 downlink can be done by any antenna/FM radio(or SDR), and computer combination of your liking. Just as one example, my setup is:
TX: Windows PC > DopplerPSK > Signalink > FT-857d > MyAntennas EFHW-8010
RX: 70cm X-Quad > SDRPlay RSP1 > HDSDR on Windows PC (doppler track w/ Orbitron) > FLDigi
-Scott, K4KDR
==============================
On Wed, Jun 12, 2019 at 8:20 PM [email protected] [email protected] wrote:
I'm very curious about this, thanks for sharing the links.
Looks like the program adjusts the PSK modulation within the pass band of the uplink, and at 10 meters, that would be relatively small. It makes sense, however would this work if SatPC32 manages the uplink ?
Secondly, I came across this on the website:
"DopplerPSK does not provide any PSK31 demodulation; you should use a separate program for that purpose. DopplerPSK does not provide any compensation for downlink Doppler (which you would need for fully linear transponders)."
Question 2 - why not use something like HRD for everything (doppler, psk, rotator, logging, etc) ? (I believe I tried it sometime back by routing of the downlink audio back into HRD)
73! Umesh k6vug
On Wednesday, June 12, 2019, 8:10:11 AM PDT, Scott via AMSAT-BB < [email protected]> wrote:
I originally used the link on 2M0SQL's excellent how-to page:
https://www.2m0sql.com/2018/10/29/using-the-no-84-psat-psk-transponder/
... which is:
http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html
If that link isn't available, you're welcome to the copy I downloaded which has just been put at:
https://www.qsl.net/k/k4kdr//downloads/DopplerPSK_0.2.zip
-Scott, K4KDR
==========================
On Wed, Jun 12, 2019 at 10:53 AM Roy Dean via AMSAT-BB <[email protected]
wrote:
With all this talk of NO-84, and me finally having a semi-operational ground station - I went looking for DopplerPSK, but every link I found
was
broken. Where can I get this software?
--Roy K3RLD
_______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
_______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Hi, I use Kenwood TS-711 for sat qsos, its a 2m multimode rig, it has sister rig, TS-811 for 70cm band, both has 10Hz steps on all modes.
Regards,
:Jari / oh2fqv
On Thu, Jun 13, 2019 at 3:37 PM Robert Bruninga via AMSAT-BB < [email protected]> wrote:
Question. All FM-only rigs of course only do 5 KHz steps anyway. Are we finding that multi-mode rigs when placed in FM mode can actually step smaller under CAT control?
If so, then we must point that out to users, since it will not work for PSK31 even in FM.
Thanks for the reminder. If rigs do that, then I will add this to the PSAT web page. The advice to not use auto-radio tuning except for 5 KHz steps on the downlink. IE, not smaller steps.
Bob, WB4APR
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of aflowers--- via AMSAT-BB Sent: Wednesday, June 12, 2019 10:58 PM To: [email protected]; Scott [email protected] Subject: Re: [amsat-bb] DopplerPSK
Scott, Roy, Umesh, et al; Part of the problem with PSK31 is that it required the adjustment for changes in Doppler shift to be to be phase-continuous. I think the Doppler rate (delta-Doppler shift) at even 10m is too fast for most radios--what you often get with CAT control, even if you can update while transmitting, is PSK31 that jumps more than 31Hz per update, and that totally destroys the phase continuity required to tell a '1' from '0'. This was the "fun" problem that spurred me to take a swing at it over a summer vacation. When DopplerPSK applies "anti-doppler" on the transmitted signal, it does so at the baseband audio level. This works fine for 3Khz passbands on a 10m uplink, but if you want to do it with SSB transponders and VHF and UHF you'll need an SDR where you aren't limited by an IF filter. The same algorithm in DopplerPSK could be used on a complex signal in the SDR architecture, and it could work equally on TX and RX in the processing chain. To the accuracy of the orbital elements everyone uses, if everyone corrects their uplink and downlink properly there is no perceived frequency drift by anyone using the satellite. Just what you need for a GHz-range LEO with a narrow-band transponder, eh? Since the downlink of NO-84 is FM there is no Doppler shift in the baseband audio of the downlink--you hear what the satellite hears. If we get a mode-K satellite it might be worthwhile to do a baseband demodulator in a soundcard since the total change in Doppler shift will be small enough to fit in a conventional HF radio's IF passband in both directions. If the antiquated hosting site doesn't come back I'll get off my duff and find a "proper" place for it. It's nice to see people playing around with it. (Thanks for bridging the gap in the meantime, Peter.) Andy K0SM/2
On Wednesday, June 12, 2019, 9:24:12 PM EDT, Scott via AMSAT-BB[email protected] wrote:
While it might certainly be possible to put together a solution that would compensate your uplink so that its corresponding downlink through the transponder holds stationary on a single spot on the downlink audio spectrum, there are two reasons (at least) that I can think of to not go to that trouble:
#1, the DopplerPSK app takes care of it perfectly already. The work has been done.
#2, if memory serves, some radios do not respond to CAT frequency adjustments when transmitting. In this mode, your uplink radio is transmitting non-stop for the entire ~10 minute pass. If you have a hardware/software setup that can only change RF frequency when in receive mode, that will never happen during an NO-84 pass.
Lastly, like much satellite work, the uplink and downlink are two completely separate discussions in this mode. While the 10m uplink works extremely well with the DopplerPSK software and the HF radio of your choice, receiving & demodulating the PSK31 downlink can be done by any antenna/FM radio(or SDR), and computer combination of your liking. Just as one example, my setup is:
TX: Windows PC > DopplerPSK > Signalink > FT-857d > MyAntennas EFHW-8010
RX: 70cm X-Quad > SDRPlay RSP1 > HDSDR on Windows PC (doppler track w/ Orbitron) > FLDigi
-Scott, K4KDR
==============================
On Wed, Jun 12, 2019 at 8:20 PM [email protected] [email protected] wrote:
I'm very curious about this, thanks for sharing the links.
Looks like the program adjusts the PSK modulation within the pass band of the uplink, and at 10 meters, that would be relatively small. It makes sense, however would this work if SatPC32 manages the uplink ?
Secondly, I came across this on the website:
"DopplerPSK does not provide any PSK31 demodulation; you should use a separate program for that purpose. DopplerPSK does not provide any compensation for downlink Doppler (which you would need for fully linear transponders)."
Question 2 - why not use something like HRD for everything (doppler, psk, rotator, logging, etc) ? (I believe I tried it sometime back by routing of the downlink audio back into HRD)
73! Umesh k6vug
On Wednesday, June 12, 2019, 8:10:11 AM PDT, Scott via AMSAT-BB < [email protected]> wrote:
I originally used the link on 2M0SQL's excellent how-to page:
https://www.2m0sql.com/2018/10/29/using-the-no-84-psat-psk-transponder/
... which is:
http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html
If that link isn't available, you're welcome to the copy I downloaded which has just been put at:
https://www.qsl.net/k/k4kdr//downloads/DopplerPSK_0.2.zip
-Scott, K4KDR
==========================
On Wed, Jun 12, 2019 at 10:53 AM Roy Dean via AMSAT-BB <
wrote:
With all this talk of NO-84, and me finally having a semi-operational ground station - I went looking for DopplerPSK, but every link I found
was
broken. Where can I get this software?
--Roy K3RLD
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Bob,
Yes they can correct too much smaller with CAT control, for NO-84 PSK I have SatPC32 correct my IC-910 every 600Hz this doesn't appear to present any problems and I've had many contacts.
Is there a reason why you're suggesting this isn't OK?
73,
Peter, 2M0SQL
On Thu, 13 Jun 2019 at 13:35, Robert Bruninga via AMSAT-BB [email protected] wrote:
Question. All FM-only rigs of course only do 5 KHz steps anyway. Are we finding that multi-mode rigs when placed in FM mode can actually step smaller under CAT control?
If so, then we must point that out to users, since it will not work for PSK31 even in FM.
Thanks for the reminder. If rigs do that, then I will add this to the PSAT web page. The advice to not use auto-radio tuning except for 5 KHz steps on the downlink. IE, not smaller steps.
Bob, WB4APR
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of aflowers--- via AMSAT-BB Sent: Wednesday, June 12, 2019 10:58 PM To: [email protected]; Scott [email protected] Subject: Re: [amsat-bb] DopplerPSK
Scott, Roy, Umesh, et al; Part of the problem with PSK31 is that it required the adjustment for changes in Doppler shift to be to be phase-continuous. I think the Doppler rate (delta-Doppler shift) at even 10m is too fast for most radios--what you often get with CAT control, even if you can update while transmitting, is PSK31 that jumps more than 31Hz per update, and that totally destroys the phase continuity required to tell a '1' from '0'. This was the "fun" problem that spurred me to take a swing at it over a summer vacation. When DopplerPSK applies "anti-doppler" on the transmitted signal, it does so at the baseband audio level. This works fine for 3Khz passbands on a 10m uplink, but if you want to do it with SSB transponders and VHF and UHF you'll need an SDR where you aren't limited by an IF filter. The same algorithm in DopplerPSK could be used on a complex signal in the SDR architecture, and it could work equally on TX and RX in the processing chain. To the accuracy of the orbital elements everyone uses, if everyone corrects their uplink and downlink properly there is no perceived frequency drift by anyone using the satellite. Just what you need for a GHz-range LEO with a narrow-band transponder, eh? Since the downlink of NO-84 is FM there is no Doppler shift in the baseband audio of the downlink--you hear what the satellite hears. If we get a mode-K satellite it might be worthwhile to do a baseband demodulator in a soundcard since the total change in Doppler shift will be small enough to fit in a conventional HF radio's IF passband in both directions. If the antiquated hosting site doesn't come back I'll get off my duff and find a "proper" place for it. It's nice to see people playing around with it. (Thanks for bridging the gap in the meantime, Peter.) Andy K0SM/2
On Wednesday, June 12, 2019, 9:24:12 PM EDT, Scott via AMSAT-BB[email protected] wrote:
While it might certainly be possible to put together a solution that would compensate your uplink so that its corresponding downlink through the transponder holds stationary on a single spot on the downlink audio spectrum, there are two reasons (at least) that I can think of to not go to that trouble:
#1, the DopplerPSK app takes care of it perfectly already. The work has been done.
#2, if memory serves, some radios do not respond to CAT frequency adjustments when transmitting. In this mode, your uplink radio is transmitting non-stop for the entire ~10 minute pass. If you have a hardware/software setup that can only change RF frequency when in receive mode, that will never happen during an NO-84 pass.
Lastly, like much satellite work, the uplink and downlink are two completely separate discussions in this mode. While the 10m uplink works extremely well with the DopplerPSK software and the HF radio of your choice, receiving & demodulating the PSK31 downlink can be done by any antenna/FM radio(or SDR), and computer combination of your liking. Just as one example, my setup is:
TX: Windows PC > DopplerPSK > Signalink > FT-857d > MyAntennas EFHW-8010
RX: 70cm X-Quad > SDRPlay RSP1 > HDSDR on Windows PC (doppler track w/ Orbitron) > FLDigi
-Scott, K4KDR
==============================
On Wed, Jun 12, 2019 at 8:20 PM [email protected] [email protected] wrote:
I'm very curious about this, thanks for sharing the links.
Looks like the program adjusts the PSK modulation within the pass band of the uplink, and at 10 meters, that would be relatively small. It makes sense, however would this work if SatPC32 manages the uplink ?
Secondly, I came across this on the website:
"DopplerPSK does not provide any PSK31 demodulation; you should use a separate program for that purpose. DopplerPSK does not provide any compensation for downlink Doppler (which you would need for fully linear transponders)."
Question 2 - why not use something like HRD for everything (doppler, psk, rotator, logging, etc) ? (I believe I tried it sometime back by routing of the downlink audio back into HRD)
73! Umesh k6vug
On Wednesday, June 12, 2019, 8:10:11 AM PDT, Scott via AMSAT-BB < [email protected]> wrote:
I originally used the link on 2M0SQL's excellent how-to page:
https://www.2m0sql.com/2018/10/29/using-the-no-84-psat-psk-transponder/
... which is:
http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html
If that link isn't available, you're welcome to the copy I downloaded which has just been put at:
https://www.qsl.net/k/k4kdr//downloads/DopplerPSK_0.2.zip
-Scott, K4KDR
==========================
On Wed, Jun 12, 2019 at 10:53 AM Roy Dean via AMSAT-BB <[email protected]
wrote:
With all this talk of NO-84, and me finally having a semi-operational ground station - I went looking for DopplerPSK, but every link I found
was
broken. Where can I get this software?
--Roy K3RLD
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Hi Armand, others
I have had the rig for 10 years and yes, it does have 10Hz step also in FM mode. I actually check that with my rig, before I post my message. Normal step for FM is 5KHz, 12,5KHz and 25KHz, but with continuous tune mode, it goes to 10Hz with FM
Regards,
:Jari / oh2fqv
On Thu, Jun 13, 2019 at 5:25 PM Peter Goodhall (2M0SQL) via AMSAT-BB < [email protected]> wrote:
Bob,
Yes they can correct too much smaller with CAT control, for NO-84 PSK I have SatPC32 correct my IC-910 every 600Hz this doesn't appear to present any problems and I've had many contacts.
Is there a reason why you're suggesting this isn't OK?
73,
Peter, 2M0SQL
On Thu, 13 Jun 2019 at 13:35, Robert Bruninga via AMSAT-BB [email protected] wrote:
Question. All FM-only rigs of course only do 5 KHz steps anyway. Are we finding that multi-mode rigs when placed in FM mode can actually step smaller under CAT control?
If so, then we must point that out to users, since it will not work for PSK31 even in FM.
Thanks for the reminder. If rigs do that, then I will add this to the
PSAT
web page. The advice to not use auto-radio tuning except for 5 KHz
steps on
the downlink. IE, not smaller steps.
Bob, WB4APR
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of aflowers--- via AMSAT-BB Sent: Wednesday, June 12, 2019 10:58 PM To: [email protected]; Scott [email protected] Subject: Re: [amsat-bb] DopplerPSK
Scott, Roy, Umesh, et al; Part of the problem with PSK31 is that it required the adjustment for changes in Doppler shift to be to be phase-continuous. I think the
Doppler
rate (delta-Doppler shift) at even 10m is too fast for most radios--what
you
often get with CAT control, even if you can update while transmitting, is PSK31 that jumps more than 31Hz per update, and that totally destroys the phase continuity required to tell a '1' from '0'. This was the "fun" problem that spurred me to take a swing at it over a summer vacation. When DopplerPSK applies "anti-doppler" on the transmitted signal, it
does so
at the baseband audio level. This works fine for 3Khz passbands on a 10m uplink, but if you want to do it with SSB transponders and VHF and UHF you'll need an SDR where you aren't limited by an IF filter. The same algorithm in DopplerPSK could be used on a complex signal in the SDR architecture, and it could work equally on TX and RX in the processing chain. To the accuracy of the orbital elements everyone uses, if
everyone
corrects their uplink and downlink properly there is no perceived
frequency
drift by anyone using the satellite. Just what you need for a GHz-range
LEO
with a narrow-band transponder, eh? Since the downlink of NO-84 is FM
there
is no Doppler shift in the baseband audio of the downlink--you hear what
the
satellite hears. If we get a mode-K satellite it might be worthwhile to
do
a baseband demodulator in a soundcard since the total change in Doppler shift will be small enough to fit in a conventional HF radio's IF
passband
in both directions. If the antiquated hosting site doesn't come back I'll get off my duff and find a "proper" place for it. It's nice to see people playing around
with
it. (Thanks for bridging the gap in the meantime, Peter.) Andy K0SM/2
On Wednesday, June 12, 2019, 9:24:12 PM EDT, Scott via AMSAT-BB[email protected] wrote:
While it might certainly be possible to put together a solution that
would
compensate your uplink so that its corresponding downlink through the transponder holds stationary on a single spot on the downlink audio spectrum, there are two reasons (at least) that I can think of to not go
to
that trouble:
#1, the DopplerPSK app takes care of it perfectly already. The work has been done.
#2, if memory serves, some radios do not respond to CAT frequency adjustments when transmitting. In this mode, your uplink radio is transmitting non-stop for the entire ~10 minute pass. If you have a hardware/software setup that can only change RF frequency when in receive mode, that will never happen during an NO-84 pass.
Lastly, like much satellite work, the uplink and downlink are two completely separate discussions in this mode. While the 10m uplink works extremely well with the DopplerPSK software and the HF radio of your choice, receiving & demodulating the PSK31 downlink can be done by any antenna/FM radio(or SDR), and computer combination of your liking. Just
as
one example, my setup is:
TX: Windows PC > DopplerPSK > Signalink > FT-857d > MyAntennas EFHW-8010
RX: 70cm X-Quad > SDRPlay RSP1 > HDSDR on Windows PC (doppler track w/ Orbitron) > FLDigi
-Scott, K4KDR
==============================
On Wed, Jun 12, 2019 at 8:20 PM [email protected] <[email protected]
wrote:
I'm very curious about this, thanks for sharing the links.
Looks like the program adjusts the PSK modulation within the pass band
of
the uplink, and at 10 meters, that would be relatively small. It makes sense, however would this work if SatPC32 manages the uplink ?
Secondly, I came across this on the website:
"DopplerPSK does not provide any PSK31 demodulation; you should use a separate program for that purpose. DopplerPSK does not provide any compensation for downlink Doppler (which you would need for fully
linear
transponders)."
Question 2 - why not use something like HRD for everything (doppler,
psk,
rotator, logging, etc) ? (I believe I tried it sometime back by routing of the downlink audio
back
into HRD)
73! Umesh k6vug
On Wednesday, June 12, 2019, 8:10:11 AM PDT, Scott via AMSAT-BB < [email protected]> wrote:
I originally used the link on 2M0SQL's excellent how-to page:
https://www.2m0sql.com/2018/10/29/using-the-no-84-psat-psk-transponder/
... which is:
http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html
If that link isn't available, you're welcome to the copy I downloaded which has just been put at:
https://www.qsl.net/k/k4kdr//downloads/DopplerPSK_0.2.zip
-Scott, K4KDR
==========================
On Wed, Jun 12, 2019 at 10:53 AM Roy Dean via AMSAT-BB <
wrote:
With all this talk of NO-84, and me finally having a semi-operational ground station - I went looking for DopplerPSK, but every link I
found
was
broken. Where can I get this software?
--Roy K3RLD
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
Opinions
expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
Opinions
expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership.
Opinions expressed
are solely those of the author, and do not reflect the official views of
AMSAT-NA.
Not an AMSAT-NA member? Join now to support the amateur satellite
program!
Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
My puzzlement, as well. The audio in an FM signal shouldn't change with small changes in the receiver frequency, due to the FM capture effect. That's assuming that the act of changing the frequency, even by such a small amount, doesn't "jiggle" the phase of the decoded audio in the process.
Is that the concern?
Greg KO6TH
Peter Goodhall (2M0SQL) via AMSAT-BB wrote:
Is there a reason why you're suggesting this isn't OK?
Everytime you step the radio frequency will cause a Phase shift and any PSK31 decoding will loose sync until it can rephrase. PSK31 needs phase coherence well under 31 Hz to properly decode.
Better to tell your software to only step the radio once every 2.5 KHz maybe to minimize these glitches and loss of characters while still keeping the FM signal in the passband.
Bob, WB4APR
-----Original Message----- From: Peter Goodhall (2M0SQL) [email protected] Sent: Thursday, June 13, 2019 10:22 AM To: Robert Bruninga [email protected] Cc: AMSAT-BB [email protected] Subject: Re: [amsat-bb] DopplerPSK - No 1 kHz-autotracking radio tuning
Bob,
Yes they can correct too much smaller with CAT control, for NO-84 PSK I have SatPC32 correct my IC-910 every 600Hz this doesn't appear to present any problems and I've had many contacts.
Is there a reason why you're suggesting this isn't OK?
73,
Peter, 2M0SQL
On Thu, 13 Jun 2019 at 13:35, Robert Bruninga via AMSAT-BB [email protected] wrote:
Question. All FM-only rigs of course only do 5 KHz steps anyway. Are we finding that multi-mode rigs when placed in FM mode can actually step smaller under CAT control?
If so, then we must point that out to users, since it will not work for PSK31 even in FM.
Thanks for the reminder. If rigs do that, then I will add this to the PSAT web page. The advice to not use auto-radio tuning except for 5 KHz steps on the downlink. IE, not smaller steps.
Bob, WB4APR
-----Original Message----- From: AMSAT-BB [email protected] On Behalf Of aflowers--- via AMSAT-BB Sent: Wednesday, June 12, 2019 10:58 PM To: [email protected]; Scott [email protected] Subject: Re: [amsat-bb] DopplerPSK
Scott, Roy, Umesh, et al; Part of the problem with PSK31 is that it required the adjustment for changes in Doppler shift to be to be phase-continuous. I think the Doppler rate (delta-Doppler shift) at even 10m is too fast for most radios--what you often get with CAT control, even if you can update while transmitting, is PSK31 that jumps more than 31Hz per update, and that totally destroys the phase continuity required to tell a '1' from '0'. This was the "fun" problem that spurred me to take a swing at it over a summer vacation. When DopplerPSK applies "anti-doppler" on the transmitted signal, it does so at the baseband audio level. This works fine for 3Khz passbands on a 10m uplink, but if you want to do it with SSB transponders and VHF and UHF you'll need an SDR where you aren't limited by an IF filter. The same algorithm in DopplerPSK could be used on a complex signal in the SDR architecture, and it could work equally on TX and RX in the processing chain. To the accuracy of the orbital elements everyone uses, if everyone corrects their uplink and downlink properly there is no perceived frequency drift by anyone using the satellite. Just what you need for a GHz-range LEO with a narrow-band transponder, eh? Since the downlink of NO-84 is FM there is no Doppler shift in the baseband audio of the downlink--you hear what the satellite hears. If we get a mode-K satellite it might be worthwhile to do a baseband demodulator in a soundcard since the total change in Doppler shift will be small enough to fit in a conventional HF radio's IF passband in both directions. If the antiquated hosting site doesn't come back I'll get off my duff and find a "proper" place for it. It's nice to see people playing around with it. (Thanks for bridging the gap in the meantime, Peter.) Andy K0SM/2
On Wednesday, June 12, 2019, 9:24:12 PM EDT, Scott via AMSAT-BB[email protected] wrote:
While it might certainly be possible to put together a solution that would compensate your uplink so that its corresponding downlink through the transponder holds stationary on a single spot on the downlink audio spectrum, there are two reasons (at least) that I can think of to not go to that trouble:
#1, the DopplerPSK app takes care of it perfectly already. The work has been done.
#2, if memory serves, some radios do not respond to CAT frequency adjustments when transmitting. In this mode, your uplink radio is transmitting non-stop for the entire ~10 minute pass. If you have a hardware/software setup that can only change RF frequency when in receive mode, that will never happen during an NO-84 pass.
Lastly, like much satellite work, the uplink and downlink are two completely separate discussions in this mode. While the 10m uplink works extremely well with the DopplerPSK software and the HF radio of your choice, receiving & demodulating the PSK31 downlink can be done by any antenna/FM radio(or SDR), and computer combination of your liking. Just as one example, my setup is:
TX: Windows PC > DopplerPSK > Signalink > FT-857d > MyAntennas EFHW-8010
RX: 70cm X-Quad > SDRPlay RSP1 > HDSDR on Windows PC (doppler track w/ Orbitron) > FLDigi
-Scott, K4KDR
==============================
On Wed, Jun 12, 2019 at 8:20 PM [email protected] [email protected] wrote:
I'm very curious about this, thanks for sharing the links.
Looks like the program adjusts the PSK modulation within the pass band of the uplink, and at 10 meters, that would be relatively small. It makes sense, however would this work if SatPC32 manages the uplink ?
Secondly, I came across this on the website:
"DopplerPSK does not provide any PSK31 demodulation; you should use a separate program for that purpose. DopplerPSK does not provide any compensation for downlink Doppler (which you would need for fully linear transponders)."
Question 2 - why not use something like HRD for everything (doppler, psk, rotator, logging, etc) ? (I believe I tried it sometime back by routing of the downlink audio back into HRD)
73! Umesh k6vug
On Wednesday, June 12, 2019, 8:10:11 AM PDT, Scott via AMSAT-BB < [email protected]> wrote:
I originally used the link on 2M0SQL's excellent how-to page:
https://www.2m0sql.com/2018/10/29/using-the-no-84-psat-psk-transpond er/
... which is:
http://www.frontiernet.net/~aflowers/dopplerpsk/dopplerpsk.html
If that link isn't available, you're welcome to the copy I downloaded which has just been put at:
https://www.qsl.net/k/k4kdr//downloads/DopplerPSK_0.2.zip
-Scott, K4KDR
==========================
On Wed, Jun 12, 2019 at 10:53 AM Roy Dean via AMSAT-BB <[email protected]
wrote:
With all this talk of NO-84, and me finally having a semi-operational ground station - I went looking for DopplerPSK, but every link I found
was
broken. Where can I get this software?
--Roy K3RLD
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Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: https://www.amsat.org/mailman/listinfo/amsat-bb
participants (4)
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Greg D -
Jari A -
Peter Goodhall (2M0SQL) -
Robert Bruninga