[amsat-bb] Re: frequency conversion

i8cvs domenico.i8cvs at tin.it
Tue May 8 20:19:39 PDT 2012

Hi Alan, VY2WU

It is not a rule of thumb but a simple math calculation for frequency

As an example :

If you need to receive 435.000 MHz from your UHF downconverter and your LO
is 424.996550 MHZ than you have to tune your HF receiver to the IF frequency
of 435.000 - 424.996550 = 10.00345 MHz

The image frequency or mixing product will be:

435.000 + 424.996550 = 859.99655 MHz wich is very far from the frequency
of  10.00345 MHz to wich the HF receiver is tuned so that don't worry about
because the HF receiver have input filters and the image frequency of
859.99655 MHz will be attenuated a lot of dB from the wanted IF frequency of
10.00345 MHz.

73" de

i8CVS Domenico

----- Original Message -----
From: "Alan Beck" <becka at eastlink.ca>
To: <amsat-bb at amsat.org>
Sent: Wednesday, May 09, 2012 1:43 AM
Subject: [amsat-bb] frequency conversion

> What is the rule of thumb in finding the exact frequency on the HF radio
for a given frequency on a UHF downconverter.
> My LO is 424.996550 MHZ.
> Does this create a mixing product that I then have to compensate for?
> Alan
> BTW Sold my 1978 VW Westphalia camper to get my new radioes.
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