Hi all.
Been trying K1JTs WSPR program over the past week. WSPR stands for "Weak Signal Propagation Reporter".
Its available here http://physics.princeton.edu/pulsar/K1JT/wspr.html
WSPR implements a protocol designed for probing potential propagation paths with low-power transmissions. Normal transmissions carry a station's callsign, Maidenhead grid locator, and transmitter power in dBm. The program can decode signals with S/N as low as -28 dB in a 2500 Hz bandwidth. Stations with internet access can automatically upload their reception reports to a central database called WSPRnet, which includes a mapping facility.
The WSPRnet site is located here http://wsprnet.org/drupal/ Spots of reception can be automatically uploaded by the program to the WSPRnet database, where its available for others to see or the person from which the signal originated can see how the signal was recieved at each location.
At the moment, we are testing on 144.144 MHz DIAL frequency. As the nominated WSPR freq 144.489, I saw a complaint somewhere it was to close to Alice Springs beacon.
This is what information you can find in the WSPR database, very interesting to not the difference in signal strength between 5ACY and 5ZK. And also interesting to see the signal strength slowly increase from mid afternoon to after sundown where signal was up to +15dB -
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2011-01-18 21:28 VK2KRR 144.145534 -6 0 QF34mr 20 VK5BC PF95jj 755 273
2011-01-18 21:18 VK2KRR 144.145521 -14 1 QF34mr 20 VK5BC PF95jj 755 273
2011-01-18 11:12 VK2KRR 144.145439 +14 -2 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 11:04 VK2KRR 144.145548 +1 -1 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 11:04 VK2KRR 144.145440 +15 -1 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:54 VK2KRR 144.145546 +5 -1 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:54 VK2KRR 144.145438 +7 -1 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:48 VK2KRR 144.145435 +14 0 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:48 VK2KRR 144.145543 +7 0 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:44 VK2KRR 144.145437 +10 -1 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:44 VK2KRR 144.145545 +7 -1 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:36 VK2KRR 144.145437 +3 -1 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:36 VK2KRR 144.145545 -2 -1 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:28 VK2KRR 144.145545 -14 -2 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:28 VK2KRR 144.145438 +8 -2 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:16 VK2KRR 144.145439 +6 -3 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 10:16 VK2KRR 144.145545 -2 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:06 VK2KRR 144.145546 -2 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 10:06 VK2KRR 144.145440 -5 -3 QF34mr 20 VK5ACY PF95sb 683 271
2011-01-18 09:54 VK2KRR 144.145547 0 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 09:26 VK2KRR 144.145551 -8 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 09:16 VK2KRR 144.145553 -3 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 09:06 VK2KRR 144.145557 -17 -4 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 08:54 VK2KRR 144.145561 -9 -4 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 08:44 VK2KRR 144.145564 -21 -4 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 08:20 VK2KRR 144.145568 -18 -4 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 08:12 VK2KRR 144.145570 -10 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 07:52 VK2KRR 144.145572 -15 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 07:44 VK2KRR 144.145571 -4 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 07:36 VK2KRR 144.145571 -12 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 07:24 VK2KRR 144.145571 -20 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-18 06:46 VK2KRR 144.145571 -22 -3 QF34mr 20 VK5ZK PF94jl 748 265
2011-01-16 22:52 VK6DZ 144.145571 -25 -2 OF84 10 VK2KRR QF34 2662 270
To have a few more stations transmitting and receiving would make a great difference in the data. I'd consider making a 4 way pwr divider and point an antenna to Melb, Mt Gambier, Adelaide, and Sydney.
Good to make use of otherwise idle equipment and be able to further study propagation paths. All rather automatic too, so u can concentrate on other tasks while the computer does most of the work for you.
WSPR operations on 144 MHz
-
VK4WDM
Re: WSPR operations on 144 MHz
Hi Leigh
Very interesting! I agree, lets get as many stations as active as possible. There a almost certainly times, paths, and means of propagation on the VHF and UHF bands that we don't even yet know about. It would be really good to get an FK8 on board too.
I have a vertical and a 10w transceiver that are idle most of the time. Is 10w enough power?
My laptop died last week so I need to get a new one. What system requirements would you (or others) recommend for a shack laptop used mainly for digital modes? Is connection to the internet a requirement? I don't currently have access in the shack.
73
Wayne VK4WDM
Very interesting! I agree, lets get as many stations as active as possible. There a almost certainly times, paths, and means of propagation on the VHF and UHF bands that we don't even yet know about. It would be really good to get an FK8 on board too.
I have a vertical and a 10w transceiver that are idle most of the time. Is 10w enough power?
My laptop died last week so I need to get a new one. What system requirements would you (or others) recommend for a shack laptop used mainly for digital modes? Is connection to the internet a requirement? I don't currently have access in the shack.
73
Wayne VK4WDM
Re: WSPR operations on 144 MHz
Hi
What antenna polarisation are you using? Given that you're looking for signals from anywhere I would have assumed vertical (since this is the simplest omni-directional antenna) but your statement about making a power divider feeding four antennas makes me wonder.
73
Iain
What antenna polarisation are you using? Given that you're looking for signals from anywhere I would have assumed vertical (since this is the simplest omni-directional antenna) but your statement about making a power divider feeding four antennas makes me wonder.
73
Iain
73
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
-
VK2KRR
Re: WSPR operations on 144 MHz
Wayne, Iain,
Your 10W TX would be fine. A vertical will work for Sporadic E paths, but on tropo if someone is on horizontal you will have cross polarity loss to contend with. I cant comment for everyone but I'd think most on SSB would want to use horizontal.
Im running horizontal on mine, yagis, but im in a more unique spot here where im shielded in a number of directions. So a number of small horizontal yagis with a broader beamwidth, beaming Melb, Mt Gam, Adelaide & NE would be OK for me here. Im lucky here that beaming west I can cover the bulk of VK5's and then to VK6 SE in one direction.
I think VK3BJM or some others would be able to give us good instruction on building an omni directional 2m horizontal antenna if need be.
I cant really comment on the computer system requirements, someone else may know. You dont need a internet connection to send and RX signals, but to upload them to the internet in near real time, you would need a connection. But if others hear your TX signal they can report it if they are connected.
Im only fairly new to WSPR also, so am still learning things myself.
Your 10W TX would be fine. A vertical will work for Sporadic E paths, but on tropo if someone is on horizontal you will have cross polarity loss to contend with. I cant comment for everyone but I'd think most on SSB would want to use horizontal.
Im running horizontal on mine, yagis, but im in a more unique spot here where im shielded in a number of directions. So a number of small horizontal yagis with a broader beamwidth, beaming Melb, Mt Gam, Adelaide & NE would be OK for me here. Im lucky here that beaming west I can cover the bulk of VK5's and then to VK6 SE in one direction.
I think VK3BJM or some others would be able to give us good instruction on building an omni directional 2m horizontal antenna if need be.
I cant really comment on the computer system requirements, someone else may know. You dont need a internet connection to send and RX signals, but to upload them to the internet in near real time, you would need a connection. But if others hear your TX signal they can report it if they are connected.
Im only fairly new to WSPR also, so am still learning things myself.
Re: WSPR operations on 144 MHz
Hi Leigh,
I think a halo or big wheel or dipole would be a suitable antenna for this mode. A splitter and four antennas seems like a bit of an overkill. Do you keep WSPR running when you're working SSB?
I think a halo or big wheel or dipole would be a suitable antenna for this mode. A splitter and four antennas seems like a bit of an overkill. Do you keep WSPR running when you're working SSB?
Lou - VK3ALB
Being right doesn't excuse bad behaviour
Being right doesn't excuse bad behaviour
-
VK2GOM
Re: WSPR operations on 144 MHz
One thing to be aware of is that your rig needs to be capable of full-duty operation in Tx for a 2min period. Even 50W for 2mins at full duty for a 100W capable rig will make it pretty hot...
I see from the screen shot that either a) Leigh's Tx signal is drifting, or b) VK5ACY's Rx is drifting in his receive cycle whilst VK2KRR is transmitting.
I found the only way to solve the GPS drift issue was GPS locking when I run WSPR on HF. Now I know that any drift figures I see against my callsign are drift in the receive station's receiver.
And those bright orange 'screen burn' (as I call them!) traces - WSPR doesn't need much power. Because the transmission is so narrow, and the tones vary only so slightly and are so slow, the challenge is to run only a few Watts and let the propagation that you perhaps didn't even realise was there, do the work. On 30m the band can seem dead but run 5W to a piece of wire on WSPR and be heard in Europe.
I would have thought an omni horizontal loop for 2m would be ideal if you want to preserve horizontal polarisation, or to save hassle - everyone could run vertical polarisation since pretty much everyone already has a 2m vertical. Just a suggestion!
73 - Rob VK2GOM / G0MOH
I see from the screen shot that either a) Leigh's Tx signal is drifting, or b) VK5ACY's Rx is drifting in his receive cycle whilst VK2KRR is transmitting.
I found the only way to solve the GPS drift issue was GPS locking when I run WSPR on HF. Now I know that any drift figures I see against my callsign are drift in the receive station's receiver.
And those bright orange 'screen burn' (as I call them!) traces - WSPR doesn't need much power. Because the transmission is so narrow, and the tones vary only so slightly and are so slow, the challenge is to run only a few Watts and let the propagation that you perhaps didn't even realise was there, do the work. On 30m the band can seem dead but run 5W to a piece of wire on WSPR and be heard in Europe.
I would have thought an omni horizontal loop for 2m would be ideal if you want to preserve horizontal polarisation, or to save hassle - everyone could run vertical polarisation since pretty much everyone already has a 2m vertical. Just a suggestion!
73 - Rob VK2GOM / G0MOH
-
VK2KRR
Re: WSPR operations on 144 MHz
Lou,
I always overkill... if u want the best results. No point poking my signal where there is no one listening. I have to turn WSPR off if on SSB voice.
Rob,
It drifts a little bit 0 to 3 Hz mainly. Which is fine. Doesn't matter if it drifts as long as it decodes. Ive heard drift can be up to 10Hz and it will still decode. If u have a close station with Aircraft Doppler shift on the signal the program will most probably not decode.
But the exact timing is the issue. Ive gotten onto Dimention 4 Clock Sync available here http://www.thinkman.com/dimension4/
It seems really good and ive set it up to sync mine every 15 mins.
Keep in mind were talking VHF 144 MHz not 10 MHz. Im running 20 watts as I feel thats enough for a station in VK6 to see if the conditions are good. And in poor conditions it should reach VK5 majority of the time at low levels, like what your seeing Brian decode down to -28dB etc. You could run 5W its just that its just that its going to be harder for the more distant station to have a look for you. 20 W is good for me cause ive got the IC910 on minimum output power feeding into my PA on low setting. So it all runs along really easy.
5W or less would be good for 144MHz Sporadic E detection etc, as it just bounces off the E layer. But tropo is slightly different.
The VK5's & VK4s today could have set this program up and monitored the Es cloud very easily and effortlessly.
Here is a few other decodes uploaded to the WSPR online database this afternoon -
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2011-01-19 02:48 VK2DVZ 144.145485 -13 1 QF68gd 20 VK2DAG QF56qp 199 213
2011-01-19 02:44 VK2KRR 144.145578 -23 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:34 VK2DAG 144.145515 -14 2 QF56qp 20 VK2DVZ QF68gd 199 34
2011-01-19 02:26 VK2KRR 144.145576 -20 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:24 VK2DVZ 144.145511 -15 0 QF68gd 20 VK2DAG QF56qp 199 213
2011-01-19 02:18 VK2KRR 144.145573 -26 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:06 VK2KRR 144.145573 -28 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 01:56 VK2KRR 144.145572 -25 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 00:26 VK2KRR 144.145562 -8 -1 QF34mr 20 VK5BC PF95jj 755 273
I always overkill... if u want the best results. No point poking my signal where there is no one listening. I have to turn WSPR off if on SSB voice.
Rob,
It drifts a little bit 0 to 3 Hz mainly. Which is fine. Doesn't matter if it drifts as long as it decodes. Ive heard drift can be up to 10Hz and it will still decode. If u have a close station with Aircraft Doppler shift on the signal the program will most probably not decode.
But the exact timing is the issue. Ive gotten onto Dimention 4 Clock Sync available here http://www.thinkman.com/dimension4/
It seems really good and ive set it up to sync mine every 15 mins.
Keep in mind were talking VHF 144 MHz not 10 MHz. Im running 20 watts as I feel thats enough for a station in VK6 to see if the conditions are good. And in poor conditions it should reach VK5 majority of the time at low levels, like what your seeing Brian decode down to -28dB etc. You could run 5W its just that its just that its going to be harder for the more distant station to have a look for you. 20 W is good for me cause ive got the IC910 on minimum output power feeding into my PA on low setting. So it all runs along really easy.
5W or less would be good for 144MHz Sporadic E detection etc, as it just bounces off the E layer. But tropo is slightly different.
The VK5's & VK4s today could have set this program up and monitored the Es cloud very easily and effortlessly.
Here is a few other decodes uploaded to the WSPR online database this afternoon -
Timestamp Call MHz SNR Drift Grid Pwr Reporter RGrid km az
2011-01-19 02:48 VK2DVZ 144.145485 -13 1 QF68gd 20 VK2DAG QF56qp 199 213
2011-01-19 02:44 VK2KRR 144.145578 -23 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:34 VK2DAG 144.145515 -14 2 QF56qp 20 VK2DVZ QF68gd 199 34
2011-01-19 02:26 VK2KRR 144.145576 -20 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:24 VK2DVZ 144.145511 -15 0 QF68gd 20 VK2DAG QF56qp 199 213
2011-01-19 02:18 VK2KRR 144.145573 -26 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 02:06 VK2KRR 144.145573 -28 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 01:56 VK2KRR 144.145572 -25 -2 QF34mr 20 VK5BC PF95jj 755 273
2011-01-19 00:26 VK2KRR 144.145562 -8 -1 QF34mr 20 VK5BC PF95jj 755 273
Re: WSPR operations on 144 MHz
Hi all,
Have a look at QST March 2008:
A New Spin on the Big Wheel (Cebik and Cerreto): Mar, p30
An excellent article on some variants on the idea of a Big Wheel - basically 3 single dipoles on an approx. triangular configuration, or a circle version. It claims about 10 dB gain when mounted at 6 m above ground, with a very circular, horizontally polarised pattern.
Should do the job nicely, I would have thought.
Regards,
Peter VK3PF
Have a look at QST March 2008:
A New Spin on the Big Wheel (Cebik and Cerreto): Mar, p30
An excellent article on some variants on the idea of a Big Wheel - basically 3 single dipoles on an approx. triangular configuration, or a circle version. It claims about 10 dB gain when mounted at 6 m above ground, with a very circular, horizontally polarised pattern.
Should do the job nicely, I would have thought.
Regards,
Peter VK3PF
Re: WSPR operations on 144 MHz
Anyone looking for the artical mentioned, look here, interesting idea, may have to look at building one.
http://radio-amador.net/pipermail/clust ... naHPOD.pdf
73 from Michael
VK6BHY
NWWA
----------------------------------------------------------------------------------
http://radio-amador.net/pipermail/clust ... naHPOD.pdf
73 from Michael
VK6BHY
NWWA
----------------------------------------------------------------------------------
VK3PF wrote: Hi all,
Have a look at QST March 2008:
A New Spin on the Big Wheel (Cebik and Cerreto): Mar, p30
An excellent article on some variants on the idea of a Big Wheel - basically 3 single dipoles on an approx. triangular configuration, or a circle version. It claims about 10 dB gain when mounted at 6 m above ground, with a very circular, horizontally polarised pattern.
Should do the job nicely, I would have thought.
Regards,
Peter VK3PF
-
VK2GOM
Re: WSPR operations on 144 MHz
It's looking good Leigh, and gathering some interest. That antenna design on the .pdf above looks interesting. If it's not too heavy I could get something like that above my 6m beam without overloading the pole.
As far as power goes I see on HF (mainly American) operators running big power on WSPR which kind of defeats the whole purpose. I would rather see no path with a given amount of low power, then the path become magically viable at a certain time, then it disappear again. That tells me more than being able to be heard all the time.
Same for VHF, probably 25W or so would do the trick for most of VK. At most times there would be no DX path at all, but then when things liven up propagation-wise, the paths would come alive. And with the DSP employed by the WSPR software, it will easily pull out signals from many dB below the noise.
Don't forget the web-database that WSPR populates is very powerful for interrogating once it has some data. You can interrogate it in all sorts of different ways to learn about propagation times, areas, and peaks/troughs.
73 - Rob VK2GOM / G0MOH
As far as power goes I see on HF (mainly American) operators running big power on WSPR which kind of defeats the whole purpose. I would rather see no path with a given amount of low power, then the path become magically viable at a certain time, then it disappear again. That tells me more than being able to be heard all the time.
Same for VHF, probably 25W or so would do the trick for most of VK. At most times there would be no DX path at all, but then when things liven up propagation-wise, the paths would come alive. And with the DSP employed by the WSPR software, it will easily pull out signals from many dB below the noise.
Don't forget the web-database that WSPR populates is very powerful for interrogating once it has some data. You can interrogate it in all sorts of different ways to learn about propagation times, areas, and peaks/troughs.
73 - Rob VK2GOM / G0MOH
-
VK4YEH
Re: WSPR operations on 144 MHz
Transmitting on 144.145440 20W into a vertical from QG62ll. Will be on all day There appear to be some traces at the moment 21:20z, but no decodes yet.
Tim
Tim
-
VK5PJ
- Forum Diehard
- Posts: 708
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- Location: Barossa Valley S.A
- Contact:
Re: WSPR operations on 144 MHz
Please be aware that WSPR can not tolerate any doppler on the signal, as it is a very narrow bandwidth mode, any doppler will cause it to not decode.
A few of us have already found this out on 50 MHz WSPR when aircraft have been on the path
Regards
A few of us have already found this out on 50 MHz WSPR when aircraft have been on the path
Regards
Peter Sumner, vk5pj
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill
You have enemies? Good. That means you've stood up for something, sometime in your life.
- Winston Churchill
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VK5AKK
- Frequent Poster
- Posts: 62
- Joined: Tue May 29, 2007 11:44 am
- Location: Upper Sturt, Adelaide Hills
Re: WSPR operations on 144 MHz
Had a look at WSPR on 2M Rx this morning and two thoughts came to mind.
This is surely the future for VHF and above beacons. This would also be an excellent radio club project for clubs sitting around wondering how to amuse the members. They could all be involved in getting a beacon on air and then get feedback on line as to who heard it, the strength and distance. Its a win win from both ends. Does anyone know a ZL radio club with a spare beam pointing at VK!
The other thought was what a great way to compare system performance with other stations in your area. As long as one stays constant others can play with feedlines, antennas, preamps and things and easily compare the results online.
So lets plant the seed to get some permanent beacons on air.
Cheers
Phil
This is surely the future for VHF and above beacons. This would also be an excellent radio club project for clubs sitting around wondering how to amuse the members. They could all be involved in getting a beacon on air and then get feedback on line as to who heard it, the strength and distance. Its a win win from both ends. Does anyone know a ZL radio club with a spare beam pointing at VK!
The other thought was what a great way to compare system performance with other stations in your area. As long as one stays constant others can play with feedlines, antennas, preamps and things and easily compare the results online.
So lets plant the seed to get some permanent beacons on air.
Cheers
Phil
Re: WSPR operations on 144 MHz
Hi
I'll leave mine on for the next few hours to see what happens.
Tx Fraction = 10%
Dial = 144.144000MHz
Tx = 144.145520Mhz
About 20W to a vertical antenna from PF95ih.
Set to upload spots, though nothing heard so far.
73
Iain
I'll leave mine on for the next few hours to see what happens.
Tx Fraction = 10%
Dial = 144.144000MHz
Tx = 144.145520Mhz
About 20W to a vertical antenna from PF95ih.
Set to upload spots, though nothing heard so far.
73
Iain
73
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
-
VK5AKK
- Frequent Poster
- Posts: 62
- Joined: Tue May 29, 2007 11:44 am
- Location: Upper Sturt, Adelaide Hills
Re: WSPR operations on 144 MHz
To VK5ZD,
A am hearing your WSPR signal S9 but no decode. Your trace drifts off the screen each time you Tx. It is a hot day!
Cheers
Phil
A am hearing your WSPR signal S9 but no decode. Your trace drifts off the screen each time you Tx. It is a hot day!
Cheers
Phil
Re: WSPR operations on 144 MHz
Thanks for the advise Phil.
I've set it to Rx only until I sort out the problem.
73
Iain
I've set it to Rx only until I sort out the problem.
73
Iain
73
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
Iain Crawford - VK5ZD
Munno Para West, SA - PF95ih
-
VK4YEH
Re: WSPR operations on 144 MHz
Nothing heard in my shack today - back to work tomorrow, so will try again during the weekend
Tim
Tim
Re: WSPR operations on 144 MHz
Will listen when not operating to this mode. It is has a lot of promise for things to happen, understanding parths and times. Good luck all.
-
VK5ACY
Re: WSPR operations on 144 MHz
I have been having a lot of fun with WSPR on 144.144 - today I got TX going via my laptop as my desktop PC needs surgery....
I get reliable decodes from Leigh VK2KRR over 687km path but have a bit of trouble with multiple tones created by aircraft Doppler...sometimes 3 and 4 aircraft simultaneously making multiple traces.
The attached screenshot shows one unusual case (at 1208, see 2 instances of decodes from the same transmission) where a Doppler-shifted tone decodes successfully at a level 15dB down on the 'real' signal/trace.
I get reliable decodes from Leigh VK2KRR over 687km path but have a bit of trouble with multiple tones created by aircraft Doppler...sometimes 3 and 4 aircraft simultaneously making multiple traces.
The attached screenshot shows one unusual case (at 1208, see 2 instances of decodes from the same transmission) where a Doppler-shifted tone decodes successfully at a level 15dB down on the 'real' signal/trace.
- Attachments
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-
VK2KRR
Re: WSPR operations on 144 MHz
Bill, Proof I guess that in some situations a doppler shifted signal will decode if the shift is not to severe.