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# 48 MHZ X 50 = 2400 MHZ + Ham freq's

• Subject: [amsat-bb] 48 MHZ X 50 = 2400 MHZ + Ham freq's
• From: BobsImsai8800@xxxxxxx
• Date: Mon, 9 Apr 2001 17:28:32 EDT

```Bill,

Thanks for posting the information, it is very useful.

I have been working with the same concept using a DEM VHF LO board with the
old standard Butler Oscillator seen on the no tune transverters, etc.  I have
been using a 48 MHZ ( 20 PF parallel) crystal instead.  The 48 MHZ crystal's
third harmonic is 144, and other harmonics fall in most of the higher Ham
bands.

So, I would suggest using a 48 MHZ crystal oscillator module with the
circuit.  By using a 2 meter IF for your downconverter, you could measure the
frequency of the oscillator easily.  You could also figure out the
fundamental frequency, and the harmonics of this oscillator, without having
to use a frequency counter.  Of course, a counter would help.  The harmonics
fall on many other Ham bands -- 144, 432, 1296 MHZ and all above.

The crystal oscillator modules are not adjustable in frequency and are
generally within around 50 parts per million in frequency.  At first I
avoided using one, but I have found that even the best uncompensated
oscillator will not always be were you last set it.  The modules will work
fine for this application, all you need is to do the math in your head.
Figuring the fundamental frequency error at 1/3 the 2 meter signal is easy
and so is multiplying 50 times the fundamental error for 2.4 GHZ.

TNX & 73,

Bob Seydler
K5GNA
k5gna@aol.com
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