Re: HB: Mixer Puzzle

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From: Monty N5FC (n5fc@io.com)
Date: Sun Jun 10 2001 - 19:52:05 CDT


On Sun, 10 Jun 2001 09:11:51 -0700, QRP-L, Bob N6WG wrote:
>My guess is that you have somehow configured the diodes in the mixer as a
>full wave rectifier. A FW rectifier puts out twice the incoming frequency,
>making the rectified input signal easier to filter.
>You might want to review the mixer wiring and see if it is consistent with
>other rigs using such a mixer. 73, Bob N6WG

Cool, Bob! You get the Ceeegar! In fact, I had two diodes backwards,
forming a nifty full wave rectifier (and still acting as a mixer -
HI). Turned them around, forming the correct configuration for a
diode-ring mixer, and now I get the expected beat notes.

However, all is yet not well... I still have about 20-30 db losses through
the mixer. However, this shouldn't be too hard to chase down... either I
have the trifilar transformers mis-wired, or my matched 1N5711's ain't what
they should be.

Any other ideas?

72,
monty N5FC

Monty Northrup, N5FC
Austin, Texas
e-mail: n5fc@io.com
web page (ham radio): http://www.io.com/~n5fc
web page (home): http://www.io.com/~maddog


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