Many of you may have read about the successful QSO between DJ5AR and Jan, PA3FXB using the ISS as a passive reflector, similar to airplane scatter or EME.
Using EME protocols and periods of 30 seconds, they completed the QSO using CW. This involved modifying satellite tracking software, and compensating for the Doppler shift. You can read details and hear audio files on DJ5AR's blog here:
This is quite an accomplishment, but I instantly began to wonder if it couldn't also be pulled off with much simpler equipment using WSJT software such as FSK441 (commonly used for rapidly moving meteor scatter QSO's). Doppler shift would not be a problem, even with the quick moving ISS, since the software is already optimized for short transmission periods.
It might be necessary to modify the standard messaging to allow for a complete QSO exchange to happen faster, or to shorten the periods to 15 seconds.
432 MHz has already proven to be very productive for airplane scatter, so I also wondered if 432 might be a good band for this type of experimentation. Lots of satellite operators are already equipped to operate on 432 and to track the ISS in real time with their antennas.
I'd love to hear some discussion about the possibility of this. It could open up a lot of potential grid squares on 432 and 1296 simply using FSK441.
Another problem to be solved is classifying the propagation mode in LoTW and other logging software. Would this be considered "airplane scatter" or would we have to invent a whole new name for this?
Congratulations to both hams for this accomplishment!
Hi Les, N1LS
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB to complete the International Space Station-Bounce on 1296 MHz CW QSO using the ISS as a passive reflector ?
Thanks for the information
73" de i8CVS Domenico
----- Original Message ----- From: "Les Rayburn" les@highnoonfilm.com To: "AMSAT Mailing List" amsat-bb@amsat.org; vhf@w6yx.stanford.edu; "WSJT Group" wsjtgroup@yahoogroups.com; "Sean, KX9X Kutzko" kx9x@arrl.org; "Marshall-K5QE" k5qe@k5qe.com Sent: Monday, May 27, 2013 11:27 PM Subject: [amsat-bb] International Space Station-Bounce on 1296 MHz
Many of you may have read about the successful QSO between DJ5AR and Jan, PA3FXB using the ISS as a passive reflector, similar to airplane scatter or EME.
Using EME protocols and periods of 30 seconds, they completed the QSO using CW. This involved modifying satellite tracking software, and compensating for the Doppler shift. You can read details and hear audio files on DJ5AR's blog here:
This is quite an accomplishment, but I instantly began to wonder if it couldn't also be pulled off with much simpler equipment using WSJT software such as FSK441 (commonly used for rapidly moving meteor scatter QSO's). Doppler shift would not be a problem, even with the quick moving ISS, since the software is already optimized for short transmission periods.
It might be necessary to modify the standard messaging to allow for a complete QSO exchange to happen faster, or to shorten the periods to 15 seconds.
432 MHz has already proven to be very productive for airplane scatter, so I also wondered if 432 might be a good band for this type of experimentation. Lots of satellite operators are already equipped to operate on 432 and to track the ISS in real time with their antennas.
I'd love to hear some discussion about the possibility of this. It could open up a lot of potential grid squares on 432 and 1296 simply using FSK441.
Another problem to be solved is classifying the propagation mode in LoTW and other logging software. Would this be considered "airplane scatter" or would we have to invent a whole new name for this?
Congratulations to both hams for this accomplishment!
-- 73,
Les Rayburn, N1LF 121 Mayfair Park Maylene, AL 35114 EM63nf
6M VUCC #1712 AMSAT #38965 Grid Bandits #222 Southeastern VHF Society Central States VHF Society Life Member Six Club #2484
Active on 6 Meters thru 1296, 10GHz & Light
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 Tue, 28/5/13, i8cvs domenico.i8cvs@tin.it wrote:
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB
Hi Domenico,
DJ5AR was using a 3m dish (29 dB gain) and 200 watts, PA3FXB also had a 3m dish but I don't know the power output.
They each have a report on the QSO in the 432 and Above EME Newsletter
http://www.nitehawk.com/rasmit/NLD/eme0713.pdf
73 Trevor M5AKA
Hi all, does anybody know what kind of rotators are they using?
Tracking ISS is quite different from tracking the Moon. Thanks.
73s Fabio IZ5XRC
On Tue, May 28, 2013 at 10:13 AM, M5AKA m5aka@yahoo.co.uk wrote:
--- On Tue, 28/5/13, i8cvs domenico.i8cvs@tin.it wrote:
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB
Hi Domenico,
DJ5AR was using a 3m dish (29 dB gain) and 200 watts, PA3FXB also had a 3m dish but I don't know the power output.
They each have a report on the QSO in the 432 and Above EME Newsletter
http://www.nitehawk.com/rasmit/NLD/eme0713.pdf
73 Trevor M5AKA
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
WOW !
From my modest EIRP calculation via the handbook that will be about 129130 W (129KW) (some error included...)
That's a huge power...
73
El 28/05/13 04:13, M5AKA escribió:
--- On Tue, 28/5/13, i8cvs domenico.i8cvs@tin.it wrote:
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB
Hi Domenico,
DJ5AR was using a 3m dish (29 dB gain) and 200 watts, PA3FXB also had a 3m dish but I don't know the power output.
They each have a report on the QSO in the 432 and Above EME Newsletter
http://www.nitehawk.com/rasmit/NLD/eme0713.pdf
73 Trevor M5AKA
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
Hi Pavel ,CO7WT
From info received belove by Trevor M5AKA we know that
DJ5AR was using a 3m dish (29 dB gain) and 200 watts at the dish feed.
If 200 W is the RF power arriving at the dish feed without losses in the feed line my calculation shows:
29 dB is equivalent to 29 dB isotropic gain so that the isotropic power ratio is 10^2.9 = 794.328 time in power.
The EIRP ( Effective Isotropic Radiated Power) is :
200 W x 794.328 = 158865.647 watt = 159 kW (rounded)
73" de
i8CVS Domenico
----- Original Message ----- From: "Ing. Pavel Milanes Costa" co7wt@frcuba.co.cu To: amsat-bb@amsat.org Sent: Tuesday, May 28, 2013 3:20 PM Subject: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz
WOW !
From my modest EIRP calculation via the handbook that will be about 129130 W (129KW) (some error included...)
That's a huge power...
73
El 28/05/13 04:13, M5AKA escribió:
--- On Tue, 28/5/13, i8cvs domenico.i8cvs@tin.it wrote:
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB
Hi Domenico,
DJ5AR was using a 3m dish (29 dB gain) and 200 watts, PA3FXB also had a 3m dish but I don't know the power > output.
They each have a report on the QSO in the 432 and Above EME Newsletter
http://www.nitehawk.com/rasmit/NLD/eme0713.pdf
73 Trevor M5AKA
Yes Domenico.
That's why I write "From my modest EIRP calculation", becouse there is a few variables that are unknown to me...
Never the less, that eve more huge power... hi hi hi ...
73
El 29/05/13 14:44, i8cvs escribió:
Hi Pavel ,CO7WT
From info received belove by Trevor M5AKA we know that DJ5AR was using a 3m dish (29 dB gain) and 200 watts at the dish feed.
If 200 W is the RF power arriving at the dish feed without losses in the feed line my calculation shows:
29 dB is equivalent to 29 dB isotropic gain so that the isotropic power ratio is 10^2.9 = 794.328 time in power.
The EIRP ( Effective Isotropic Radiated Power) is :
200 W x 794.328 = 158865.647 watt = 159 kW (rounded)
73" de
i8CVS Domenico
----- Original Message ----- From: "Ing. Pavel Milanes Costa" co7wt@frcuba.co.cu To: amsat-bb@amsat.org Sent: Tuesday, May 28, 2013 3:20 PM Subject: [amsat-bb] Re: International Space Station-Bounce on 1296 MHz
WOW !
From my modest EIRP calculation via the handbook that will be about 129130 W (129KW) (some error included...)
That's a huge power...
73
El 28/05/13 04:13, M5AKA escribió:
--- On Tue, 28/5/13, i8cvs domenico.i8cvs@tin.it wrote:
Do you know the EIRP used at 1296 MHz by DJ5AR or by PA3FXB
Hi Domenico,
DJ5AR was using a 3m dish (29 dB gain) and 200 watts, PA3FXB also had a 3m dish but I don't know the power > output.
They each have a report on the QSO in the 432 and Above EME Newsletter
http://www.nitehawk.com/rasmit/NLD/eme0713.pdf
73 Trevor M5AKA
participants (5)
-
Fabio Azzarello -
i8cvs -
Ing. Pavel Milanes Costa -
Les Rayburn -
M5AKA