On Sun, Jan 20, 2008 at 02:03:57PM -0400, Bruce Robertson wrote:
On Jan 20, 2008 12:44 PM, Stefano Simonetti iw1rdz@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
http://www.db.net/~db/gen_2400.pdf
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@FreeBSD.org db@db.net http://www.db.net/~db