[amsat-bb] Re: mode s converter

Bruce Robertson ve9qrp at gmail.com
Sun Jan 20 10:03:57 PST 2008

On Jan 20, 2008 12:44 PM, Stefano Simonetti <iw1rdz at yahoo.it> wrote:
> Hi to all, I would like to test my "old" AO40 13cm converter (2400-2402MHz) to see if it is still alive...
> I have not any kind of RF generator and I am wondering if some satellite has now active some tx in that band.
> Thanks, 73
>  IW1RDZ - Steve


I don't believe there is a permanent S-band signal in LEO that makes
an easy means of testing your downconverter. The CanX-2 cubesat will
have a downlink in s-band, but some modulation modes are less useful
for setting up a system than others, and I can't tell what modulation
they'll be using, or on what frequency, exactly.

I guess we might have S-band from the ISS some time soon, too.

If you need a cheap-and-dirty signal source, try using one of those
small, canned RF oscillators at 40 MHz. Properly powered with a 5v
voltage regulator and a 9v battery, it will produce a harmonic signal
that you'll hear well from right next to the downconverter, and, with
a gain antenna, from some distance away. Don't worry about building it
an antenna. If you're not sure if what you're hearing is the sig gen.
or a birdie, just blow on the sig gen, and its frequency will warp!

At $2, it was all I used to hack and tweak my downconverter. I got
this idea from a VE2 ham's webpages, but I can't seem to google them
up right now.

More information about the AMSAT-BB mailing list