[amsat-bb] Re: mode s converter

Diane Bruce db at db.net
Sun Jan 20 11:29:32 PST 2008

On Sun, Jan 20, 2008 at 02:03:57PM -0400, Bruce Robertson wrote:
> 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...
> >
> 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

It works a treat. There is a design using a filter
here: http://www.g4dmf.co.uk/2400/2400.html I've not gotten around
to building it.

> 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!

The problem with the xtal module is which harmonic are you listening to?
It's good enough for tweaking your converter and making sure things work,
but it's not going to reliable to use as a frequency standard. ;-)

> 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.

I took one off an old 386sx board; Just about any old
xtal module will multiply up into 2.4.

- 73 Diane VA3DB
- db at FreeBSD.org db at db.net http://www.db.net/~db

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