Sat Friends,
Have you noticed the confluence of satellites scheduled to be launched in 2009? With the recent SSETI-ESEO news it seems that there is a good chance that P3E, SSETI and maybe even Eagle will fly in the 2009 time frame (plus/minus the normal delays).
While that seems like a long time to have to wait, it also provides the opportunity to begin planning a new groundstation that can take advantage of the 2009 "Feast of Satellites."
It's been years since the AO-40 failure and over a decade since AO-13 went sub-orbital. I can't be the only satellite enthusiast who could certainly do with a complete station overhaul?
I hope we will see much discussion on the -BB about assembling new stations, new antennas and accessories. Since a person could invest a lot of money on equipment, it would be useful to have some published guidelines. Perhaps a series of articles in the Journal and other publications will be forthcoming as we all prepare for a new generation of satellite fun!
Just something to think about. Having to wait such a long time for these projects to come to fruition is frustrating but it also offers enough time to begin saving for new equipment and assembling and testing everything required so we are all ready to use the new birds when they appear on the horizon.
73, Jeff KE9V
Quoting "Jeff Davis, KE9V" jl.davis@gmail.com:
Sat Friends,
Have you noticed the confluence of satellites scheduled to be launched in 2009? With the recent SSETI-ESEO news it seems that there is a good chance that P3E, SSETI and maybe even Eagle will fly in the 2009 time frame (plus/minus the normal delays).
While that seems like a long time to have to wait, it also provides the opportunity to begin planning a new groundstation that can take advantage of the 2009 "Feast of Satellites."
Jeff:
I, too, am trying slowly to improve my homebrew antenna set-up so that it will be HEO-ready.
I don't have a dish up for s-band, but when I do, I plan to test it using the advice on http://www.amsat.org/amsat/articles/g3ruh/116.html (Hey, here's a cool computer programming job: a little application that takes the sound volume samples and also pulls the sun noise value from the Internet. Extra points for being able to take multiple samples or graph G/T ratio over time.)
As for mode U/V, what I really need to test this is a LEO satellite to launch with a SSB/CW transponder and very low power. Hey, how about that: Delfi C3!
Using a modified version of the spreadsheet at http://www.amsat.org/amsat-new/echo/Echo_Linkbudget.php to do the link calculations, I've worked out the following, assuming 0 dB antenna gain, no polarization loss, no atmospheric loss, and 2m signals in both cases. Fancy things like squint angle aren't calculated in, either.
*Delfi C3* Max range: 2500km Power: 0.4W signal: -117 dBm
*P3E* Range: 20,000km (not max, but in the ballpark) Power: 30W (just a guess, folks) signal: -117 dBm
At max range of P3E, say worst case of 50,000 km, we have a -125 dBm signal to contend with. Perhaps we can bribe the good folks at U. Delfi temporarily to drop the transmit power to .04W and we'll have a good idea of what's what at that range, too :-)
The power specified for P3E 2m transmit is loosely based on that of previous P3 birds. Given its larger size, I expect that P3E will have more directional, and therefore higher-gain, antennas. I'm also not sure if doing the test right at the horizon is such a good idea: I find signals pretty choppy there, presumably due to ground reflections. Perhaps a ~2000km distance at about 8 deg. would be a better point of comparison. In any case, what I'm trying to demonstrate is that these two power levels are similar, not that the estimated signal strength is an accurate number.
Now we just need to remember that Delfi C3 won't need HEO-type uplink power :-)
I'm taking this approach because I believe it is quite difficult to characterize my antenna/preamp/cable/receiver system noise temp. at 2m without some serious test equipment. Does anyone have some tips on this, or have some basic figures for common equipment, such as the FT-847 and TS-2000, and the ARR or SSBUSA preamps?
73, Bruce VE9QRP
participants (2)
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Bruce Robertson -
Jeff Davis, KE9V