[amsat-bb] ISS Packet Frequency?

Stewart Todd Morgan morgan_st at bellsouth.net
Thu Apr 27 23:23:48 UTC 2017

Yes, I can, but I'm not complaining about performance.  The point of the 
TH-D72A vs. IC-02AT test was to see if evidence existed to support the 
notion that there might be some anomaly with the new ISS APRS system 
that might explain why some operators (Scott, K4KDR and others 
apparently) are unable to decode packets now when they could previously, 
either on 70 cm or 2 m.  If my comparison test had come up, say, 13 to 2 
packets decoded in favor of the TH-D72A, that would lend credence to the 
notion that such an anomaly might exist but is masked by the better 
performance of purpose-built (i.e. designed for packet/APRS) equipment 
like Kenwood and Yaesu transceivers.

When you have a measure of experience with something like ISS APRS 
reception, it's easy to brush off reports like Scott's and just chalk 
them up to operator ignorance, operator incompetence, simply forgetting 
a step or two in a setup process, etc.  But Scott is asking for some 
help (a sanity check), and I was just trying to perform a few 
independent tests.  There are plenty of other operators who could do the 
same thing.

So now the question would seem to turn to things like:

What do Scott's station and the others have in common (if anything)?  
Are they all SDR type stations?
If they are SDR stations, are typical SDR stumbling blocks handled 
properly (offset, center spike at 0 Hz offset, etc.)
Are the station components and transmission lines well shielded?
Have local interference sources come into existence on or near 145.825 
MHz since the ISS was previously on that frequency?


On 4/27/2017 9:18 AM, Norm n3ykf wrote:
> Can you record the RF on an SDR and make multiple tries decoding?
> Norm n3ykf

More information about the AMSAT-BB mailing list