[amsat-bb] A tip for Gqrx users and report of the copy of FIREBIRD-II FU3/4 19k2 FSK.

M.Sc. Pavel Milanes Costa co7wt at frcuba.co.cu
Thu Oct 15 03:24:37 UTC 2015

I'm playing this night with my linux box and rtl-dsr + Gqrx + Gpredict 
to see the 70cm satellite sub-band...

And found a way to identify the sat from the spectrum at a glance in 
70cm using the bookmarks of gqrx... very handy feature of this 
software... just linux here, not know if windows sdr soft has this 

After playing with satlist.csv (from 
http://www.ne.jp/asahi/hamradio/je9pel/satslist.htm) and parsing it to 
make it work with gqrx... I fire the Gqrx software, put up the antenna 
and watch for any suspicious signal... and the bookmarks on top of the 
signals are there, nice....

... (a few minutes after) ...  haja !!!!

A packet like signal around 437.4 Mhz, zoom it.... wow, to wide for 
normal packet... let's widen the filter to fit... ~25 Khz is enough, 
hum... it's bigger than 9600 bauds... lets see what the bookmarks on the 
screenm says... FIREBIRD-II FU4 19k2 FSK within the +/- 10khz of 
doppler... bingo !!!

Let's run Gpredict to check.... right on the spot... and also 
FIREBIRD-II FU3 incoming on range... let's check... right...

So if you use linux and some SDR hardware with Gqrx, you can use the 
bookmark function to this purpose, you can actually click & zoom and 
then read of the screen to approximate which is the satellite who tx 
that signal... all at a glance...

If any of you want to play with this I can send you my bookmark file of 
the entire 70cm satellite sub-band, updated with the last info from  
http://www.ne.jp/asahi/hamradio/je9pel/satslist.htm just email me a 
private msg.

I was not trying to decode, just to prove the usefulness of this 
feature, I use the latest gqrx & gpredict from ubuntu PPA.

BTW, none of the FIREBIRD satellites are in the 
http://www.amsat.org/status/ page, so I can't update it's state.

73 from Cuba, CO7WT

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