[HomeBrew] Re: 2 & 6 Meter Recever Kit

[Steven Coles]

Barry,

 

While I knew patching into an AM IF should work, I didn't know how well.  So. . . I decanted a 49.860-MHz baby monitor receiver to get at the MC3361 (a more modest member of the same family as the MC3362).  For the AM IF amplifier I opened a Radio Shack 12-889 AM/FM/Weather Radio.  The first step was tying the grounds together.  After removing the 455 ceramic filter from the baby monitor, I patched the monitor's second converter output into 12-889's 455-kHz filter input.  All unnecessary shunting impedances had to be disconnected.

 

A toy walkie-talkie supplied 49.860-MHz AM source.  The method provides enough gain to get feedback with the walkie-talkie about 15 feet distant from the receiver.  If I changed one of the baby monitor local oscillator crystals to 39.7 MHz and tuned the input coil slug, I could monitor local 50.4-MHz AM activity.

 

Now let's see. . . add a BFO and. . .

 

73,

 

Steven