[amsat-bb] Re: Help in Hearing ISS

Alan wa4sca at gmail.com
Mon May 27 09:14:19 PDT 2013


1.  Working the ISS, or any other satellite where the uplink and downlink are in the same band, is
handled by a special version called SATPC32ISS. This is one of the several support programs which come
with the main program.  See the manual under Auxiliary Programs.  Handling these differently is
necessary because your rig, like other satellite rigs, is only full duplex when the uplink and
downlink are on different bands.  On two meters, the Doppler shift is low enough that you can simply
tune your radio to the nominal uplink and downlinks.  The same for packet.  In principle Doppler
tuning is better, but many just ignore it, and make contacts.  Note that this is NOT true if 70 cm or
higher are involved.

2. Packet is on 145.825 MHz.  A good source of info on what the ISS is currently doing is here:  


There many sites which talk about using software TNC programs such as AGW Packet Engine, MixW, etc.  I
would suggest looking for the information on using them with APRS, which unless you are in a really
remote location, is available 24/7 for testing.  Once that is running, switching to the ISS or other
packet satellites is relatively easy.

3.  Not very often.  Various reasons, including the fact that the other modes are very popular.

4.  You will need to use the latest Keps.  The ISS is frequently reboosted, and so until the Keps
catch up, there can be a significant different between the predicted and actual times.  Note that the
NASA.ALL Keps are only updated weekly, so be certain to use the AMATEUR.TXT which SatPC32 downloads.



-----Original Message-----
From: amsat-bb-bounces at amsat.org [mailto:amsat-bb-bounces at amsat.org] On Behalf Of Les Rayburn
Sent: Monday, May 27, 2013 10:10 AM
To: AMSAT Mailing List
Subject: [amsat-bb] Help in Hearing ISS

I ran a Google search this morning, and there is still no known cure for 
"operator error". So I resort to searching
for more medicine on the list until a cure can be found. Please give 
generously until a cure can be found. :-)

Been on satellites for about five weeks now, and have managed to work a 
few contacts through SO-50, FO-29, AO-7,
and VO-52. Have copied CW beacons from other birds including a few of 
the small Cubesats. The system
seems to be working well.

Some bugs had to be worked out along the way, including adjusting 
Doppler correction on SATPC32,
fixing an audio distortion problem, and desense in Mode J.

But despite my best efforts, I've yet to hear a single peep out of the 
International Space Station. Not just in voice modes,
mind you, but I can't seem to find the digipeater signals, or anything 
else. I'm clearly doing something wrong.

So, here are my questions:

1.) My IC-910H is controlled by SATPC32 in "satellite mode". Simple 
enough. But when I make the ISS the "active satellite" it stays in V/U 
mode, and won't easily let me go into simplex mode to work the ISS voice 
circuits or FM repeater.

Is there a fix for this? How do other IC-910H owners deal with this issue?

2.) What frequency should I be looking for the packet signals on?

I don't have a TNC, but do have a Rigblaster USB Advantage sound card 
interface. I know it's possible to use this to monitor (and possibly 
transmit signals to the ISS) Is there a link to a web site explaining 
how to configure the software, etc. for beginners?

3.) How often is the ISS in FM repeater mode? Not often, I'm guessing. 
Anyone know why?

4.) Any other tips on working the ISS? It would be quite a thrill for me!

Please pardon the newbie questions. This list is great, and I really 
appreciate the help.

We now return you to your regularly scheduled programming for smart, 
capable operators, already in

Les Rayburn, N1LF
121 Mayfair Park
Maylene, AL 35114

6M VUCC #1712
AMSAT #38965
Grid Bandits #222
Southeastern VHF Society
Central States VHF Society Life Member
Six Club #2484

Active on 6 Meters thru 1296, 10GHz & Light

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