[HBR] Crystal filter article

[Brian Burns]

Hello All,

 

"Back in the day", which was mid 1950's for me, I was an avid reader of CQ
magazine. I also read QST, but for a kid who saved his lunch money to buy
parts, the QST projects were mostly beyond my means. 

 

Dennis Regan (K6ZJU) and I (K6UCD) built the $3.96 two element beam for 15
meters out of CQ, and with a borrowed cathode modulator had a ball! The beam
was made with bamboo poles wrapped with aluminum foil, and hose clamps for
connectors!

 

So I decided to take a sentimental journey back to the issues of CQ from
that era by spending $10 to sign up for a month's access here:

 

http://hamcall.net/cq

 

I've been printing out the table of contents page for each month to keep in
a binder for reference. In the November 1955 issue there is an article
titled "A Receiver Variable Selectivity Adapter". 

 

Now this is more like it! For the dedicated do-it-myselfer it has eight
pages of real how-to instructions, including crystal grinding to raise the
crystal frequency, and a simple copper plating method for lowering crystal
frequency. It is a combination full lattice and half lattice filter with
switching to three different selectivities, so you might not want to build
the whole thing, but the article has a lot of good info. 

 

Cheers,

 

Brian

 

 



---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com