[AMRadio] Homebrew Solid-State Receiver

[Joe Bento]

Hi all,

While this list tends to concentrate primarily on vintage AM 
equipment, I'm sure some of you build solid-state projects as well.

Some of you may be familiar with Harry Lynthall's (SM0VPO) web 
pages.  He has a wealth of information for various projects and 
building blocks, both solid-state and vacuum tube.  One of the 
"building block" projects that caught my eye was a superhet 
receiver that uses the ZN414 / MK484 chip for the IF amp and 
detector.  He uses cheap IF transformers from $1.50  throwaway 
radios as well.

Considering the extremely high gain of the MK484 chip, I was 
thinking of doing some modifications to make an inexpensive 80 
meter AM receiver, completely from junkbox parts.

I was curious to know if anyone has tried using the 484 as an IF 
amp before.  The chip is typically used as a TRF receiver for the 
broadcast band,  but it should certainly function very well at 455K.  
The cheap BCB IF transformers should do an adequate job in 
limiting the bandwidth to less then 10k, which should do fine for 75 
AM.

Considering this is just a single conversion, would it make any 
difference in using high or low side injection for the local oscillator / 
VFO?

Thanks for any thoughts.


73
Joe Bento
N6DGY
Pleasant Grove, Utah