[R-390] R-390A sensitivity measurements

[Roy Morgan]

At 11:48 AM 3/2/2005, Cecil Acuff wrote:
>I've been contemplating a balun to go from the balanced input to the 
>antenna/generator anyway.  Question is do I do a 2:1 or a 1:1.

Cecil,

Try both. And let us know what happens.

I plan to install a little toroid core inside a twinax connector with a BNC 
female connector mounted in the rear of the twinax.  there's plenty of room 
for a small toroid.  I'll be glad to hear how you make out.

The TMC company in their GPR-90 receivers used a toroid input transformer 
inside at the antenna connector.  I don't know it's turns ratio.  The input 
RF amplifier tube is a 6AB4 triode in grounded grid configuration. The 
transformer is tapped for both 300 and 75 ohms input, and the crystal 
calibrator signal is fed to the 300 ohm input point.

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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