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[aprssig] PCSAT2 Downlink Challenge

John Ronan aprssig at ei7ig.org
Sat Jul 30 11:01:43 UTC 2005


> 1)   You need to replace the antennas!
No rotators here unfortunately, so a 19" Whip it will have to be  
then.  Though from reading and re-reading Bob's post, and knowing  
that these stations will be un-manned should we just leave the rigs  
on the downlink frequency and hope to receive with little or no  
doppler at the centre of the pass, or should we tune/scan between the  
frequencies most likely at the beginning/end of the pass?
>
> 2)   For work at 9600, you must tap the receive signal off the  
> radio's discriminator output

Ok, I'll try the linux soundmodem interface again later... I think I  
hung the soundcard driver trying 9k6 last night, i have the cables  
already made up to interface to the FT-847.

I did a bit of playing with the TH-D7 this morning and i have it  
running under Linux in Kiss mode.  Though I've come across a few web  
pages that seem to suggest that its very unreliable at 9K6 in kiss  
mode. Has anyone had any experience of this? bearing in mind we are  
only trying to catch a few packets of data would this suffice for a  
9K6 downlink?

I've got the machine time synced using ntp and this should give me  
the correct output, listen -t -p 70cm | tee PC2_$(date +%y%m%d_%H%M) 
_EI7IG.txt

> 3)   The TS2000 appears,
>
So for the EI8JA's TS-2000, kiss mode and add 19" Whip, AGW (which he  
has) and AGW monitor. Excellent, one hopefulle sorted.

> If you have a PC with sufficient "horsepower" (approximately  
> Pentium II 300 or higher) and a soundcard with a stereo line input,  
> the AGW PE  softmodem can be configured to act as TWO TNCs, one on  
> the left channel and one on the right channel, emulating something  
> like a Kantronics 9612 dual-port..   You could set one to 1200 baud  
> connected to one radio via the speaker output, and one to 9K6  
> connected to the other radio via the discriminator output.   Note  
> that you MUST have a line-level input to get the stereo input; the  
> mic input (often the ONLY input on laptops) is single-channel  
> (MONO) and can't use this feature of AGW PE.

Thats a very interesting idea, I'll put that to John, as he could  
then use both rigs one on the 'big vertical' and one on the 19" Whip,

Thanks for the reply.

Regards
de John
EI7IG






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