I.F. OUTPUT MIXER FOR
ICOM R8500 RECEIVER


Inspired by the 2 articles (referenced below), this is my build of an up-convertor or mixer.
The mixer is designed to frequency translate the IF output of the ICOM R8500
comms' receiver with a stable L.O. signal of 80MHz to produce a signal in the VHF band.
The idea being to view TV signals tuned on the ICOM.
According to the R8500 manufacturers manual I.F. output freq's from receiver are:
video carrier 16.2 MHz
Audio carrier 10.7 MHz
{output level -60dbm (with -50dbm input from antenna in WFM mode)}
With a "high-side" Local Oscillator injection frequency of 80 MHz
the expected output frequencies would be
Video carrier 80 - 16.2 = 63.8 MHz
Audio carrier 80 - 10.7 = 69.3 MHz
The frequency assignment for (Australia) Ch 2 is 63 - 70 MHz
This RF signals can be "tuned-in" using a conventional (analogue) TV receiver, channel selector CH 2.
I have used (again) a recycled curry-powder tin as an enclosure.
This is a good RF shield. The circuitry is attatched to a fabricated tight fitting metal "cap".
Schematic gives details; an ADE1 diode ring mixer is utilized.





References:

1) http://home.iprimus.com.au/toddemslie/AR5000TV.html

2) http://web.archive.org/web/20070202104712/http://www.aoruk.com/pdf/5000tv.pdf