View Single Post
  #37   Report Post  
Old December 25th 06, 10:54 PM posted to rec.radio.amateur.homebrew
ken scharf ken scharf is offline
external usenet poster
 
First recorded activity by RadioBanter: Jul 2006
Posts: 182
Default Older ARRL Handbooks

ken scharf wrote:
julian814 wrote:
Today, I am reminded that Google is my friend. After much digging and
prodding, I found what I was looking for. It seems the National SW-54
receiver is as close to what I want as possible without me having to do
math. It dates back to the 50's, uses tubes, (in fact, I already have
three of the five in it) covers a good amount of the SW band, and will
drive either my 2000 ohm headphones or a 4" speaker. BAMA had the
manual, but it wouldn't give it up, so I had to go to the mirror site
to get it. Everything I need is in it - schematics, parts list,
pictures of the assembled receiver. Not exactly the ideal radio for a
first try, but nothing good ever came easy, did it? ;-)

Thanks again to everyone who offered advice and suggestions. I'll be
sure to post when I have it together and let everyone know how I made
out.

Time to scrounge for parts.


Ralph

OPPS, I confused the sw-54 with the sw3-5 series.
This one is a "modern" superhet. Do you have the IF transformers, band
switch and coils?

I have a complete band switch and coil assembly from an old Lafayette
short wave receiver. It is a 4 band assembly with rf, osc, and mixer
coils intended for use with a 3 gang 365pf/section tuning capacitor.
I was thinking of using this in some project (that never happened), but
it sounds like just what you want. The coils have slug tuned tracking
adjustments, and the oscillator and mixer coils also have trimmer
capacitor tracking too.

If you can use this let me know.

PS, if you use this you'll have to change the tube lineup to take full
advantage of all the coils. Replace the 50c5 with a 35c5 and add
another 12ba6 for an rf amplifier. Actually you should use all 6v tubes
and a power transformer. Those AC/DC sets are "undertakers labs"
approved shock hazards. An "isolation transformer will fix that of course."

The schematic of the receiver the coil switch assembly came from is here
http://bama.edebris.com/manuals/lafayett/ha700/