The story of my 80/40 meter three tube (all 6U8) superhet receiver is recounted here: http://www.gadgeteer.us/erart.htm I've been playing with this RX on and off for many years now. Somewhere along the line I picked up a 455 kHz filter for it (I couldn't find the 455 kc crystals that Lew McCoy used). Yesterday I finally got around to putting the filter into the receiver. There is almost no info on this filter on the internet. Here are the details" Toyo Communications Equipment Company Ltd. CM FILTER Type: 455 -- 2.4 -- C Date: 8- 69 On the bottom, there are four terminals. They are marked "P" "B" "E" and "G". Does anyone know what these letters signify?
I experimented and it seemed like putting a 455 kc signal into P and B, and taking the output from E was the way to go. I've left G floating. It works, and the improved selectivity is very evident. But I'm operating with no specs on the filter, so I may have it in there upside down and backwards. And of course, I am operating with my usual disregard for impedance matching issues. Here's how I've placed it in the circuit:
Ideas, suggestions and even admonitions would be appreciated.
In response to popular demand, "SolderSmoke -- Global Adventures in Wireless Electronics" is now available as an e-book for Amazon's Kindle.
Here's the site:
For the print version:
For shipping from a printer in the U.S. (probably better for N. American buyers) Click here: SolderSmoke USA Version
For shipping from a printer in the UK, Spain, or the USA (probably better for UK and other European buyers)
Click here: SolderSmoke EU Version
The two versions are identical, except for a minor difference in the paper used. That's why the prices are a bit different.
Bill's OTHER Book (Warning: Not About Radio)
Click on the image to learn more
W4HBK's QRSS Grabber: The Amazing Pensacola Snapper (Live!)