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[TowerTalk] Do Log-Periodics Stress the Selectivity oftheReceiver?

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Subject: [TowerTalk] Do Log-Periodics Stress the Selectivity oftheReceiver?
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Date: Tue, 30 Nov 1999 18:23:10 EST
In a message dated 30.11.99 15:13:31 Pacific Standard Time, K7GCO writes:

<< Dave
     I said it was a 5M pre-amp.  In those days there was no 6M band --it was 
5M.  That's above 50 MHz where a 1/4 WL is about 4' of 4" tubing.  If and 
when I make it for 10M the tubing will be about 8.5' long.  Ya got it?
  K7GCO wrote---
  >      For some great reading, read the QST's and Radio Mags from the 
  > 20's &  30's.  A 39 QST had an article on a 5M RF Pre-amp with Hi-Q
  > circuits.    It used a 1/4 WL length of 4" copper tubing and copper
  center rod as 
  > the tank  circuit for the grid and plate circuit.  This should be very
  > and selective.  I picked up on this idea real fast and immediately 
  > zipped to the conclusion page to see what they would claim for
  performance.  It 
  > claimed 7 S-Units gain where 2 were noise and 5 were signal.  If true
  or close 
  > to it this needs to be made up which I will do when I get back to SD. 
  > will make these plug in copper tube 1/4 WL tank circuit so I can plug
  > into the Millen R9er......
  Did I totally misunderstand what you are saying, or was the circuit in an
  APRIL issue of QST?  I think I would have a hard time fitting a 1/4
  wavelength of 4" copper tubing into my shack...let alone into any piece
  of equipment I have ever seen...I know I don't have the means to wind it
  into any kind of a coil...and I probably can't afford that much copper.
  When I first read the above, I wondered if you meant to type "...a 1/4 WL
  of 1/4"...", but that would still be pretty hard to put into an existing
  piece of equipment. 
  I agree that many AVC circuits need improvement...but boy this idea blew
  me away.
  73 es gud dx,
  -Dave-  K9FN

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