[aprssig] 9600 Packet was RE: EB-432/PCSAT2/APRS Question

[John Ronan]

> One thing to watch for with 9600 baud sound card packet is presence of
> isolation transformers in your sound card interface... they  
> shouldn't be
> there. While isolation is generally a good thing, the transformers  
> used in
> most interfaces do not have the frequency response range necessary  
> for 9600
> operations. You could try a simple, un-insulated wire for receive  
> audio and
> see how that works. If that works, drop the transformers for both  
> RX and TX
> audio... and cross you fingers that isolation isn't critical for  
> your setup.
>
Oh, I didn't know that, though it does make sense.

I'm using one of these
http://www.melvin2.freeserve.co.uk/id26.htm


It WAS working before I switched to the EB-432, but I don't remember  
what the signal levels were, and now that the Pre-Amp is mounted  
outside, I can't try it on the omni again to compare. So all I can do  
is try one thing at the time to see if I can find what the problem is.
> Did you try the hardware modem yet? (I may have missed your report  
> -- if so,
> sorry.)
>
I did and it decoded some packets, then PCSAT2 went 'asleep'.  If it  
wakes before tomorrow morning (Irish Time) I might get a few passes  
to compare the software & hardware modems.

Thanks for the reply.

Regards
John


--
John Ronan <jronan at tssg.org>, +353-51-302938
Telecommunications Software &  Systems Group,  http://www.tssg.org