[amsat-bb] Re: mode s converter

[Bruce Robertson]

It's been a while since I've had my s-band equipment working, but as I
remember, an access point makes what appears to be an increase in the
noise level on a SSB/CW radio. (My linksys wifi router provides the
same service on all bands!) The nice thing about a signal generator is
that you have a single tone that you can hear with certainty, take
s-meter readings of, etc. When I had my downconverter and patch
antenna on my mast, I used to turn on the signal generator and point
the array at my shack, where I was holding the signal generator, as a
way of ensuring that everything was working.

Diane points out that calculating the frequency can be difficult. This
is true, but if you have an all-band radio, you can listen to the
harmonic of a 40 MHz can which should be up around 440 MHz. The error
will be multiplied 11 times, and you can use that to get a pretty good
idea of where the signal generator should appear in the s-band.

73, Bruce
VE9QRP

On Jan 20, 2008 4:24 PM, Stefano Simonetti <iw1rdz at yahoo.it> wrote:
>
> Thanks for the answers,
>
> I have here a 50MHz block, I will try, thank you, I already saw those
> projects at the ao40 days...Now finally I will make the circuit.
>
> I was also wondering if a wifi access point beacon would do the work.
>
> ISM band starts at 2400 and channel 1 is from 2401 to 2423 with the center
> of 2412.
>
> I tried but heard nothing, I don't know if there should be RF around
> 2401-2402  from an access point beacon tuned on channel 1.
>
> What do you think about?
>
> 73 - Steve - IW1RDZ
>
> ----- Messaggio originale -----
> Da: Diane Bruce <db at db.net>
> A: Bruce Robertson <ve9qrp at gmail.com>
> Cc: Stefano Simonetti <iw1rdz at yahoo.it>; AMSAT BB <amsat-bb at amsat.org>
> Inviato: Domenica 20 gennaio 2008, 20:29:32
> Oggetto: Re: [amsat-bb] Re: mode s converter
>
>
>
> 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
>
> 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 at FreeBSD.org db at db.net http://www.db.net/~db
>
>
>
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