[R-390] R-390 alignment questions

[Cecil Acuff]

Rhombic I wish.....no ladder line either.  Just a little Carolina Windom 
from Radio Works...fed unbalanced up about 50'.

Cecil...
----- Original Message ----- 
From: "Veenstra, Lester" <lester.veenstra at lmco.com>
To: "John KA1XC" <tetrode at comcast.net>; "R-390 reflector" 
<r-390 at mailman.qth.net>
Sent: Wednesday, October 13, 2004 8:07 AM
Subject: RE: [R-390] R-390 alignment questions


> Of course doing the balance nul adjustment assumes you are goung to feed
> your rhombics with long runns of latter line in a noisy environment HI
> Les K1YCM/3 (xCTM1)
>
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net
> [mailto:r-390-bounces at mailman.qth.net] On Behalf Of John KA1XC
> Sent: Tuesday, October 12, 2004 10:41 PM
> To: R-390 reflector
> Subject: Re: [R-390] R-390 alignment questions
>
>
>> I thought I would go back and input a signal on the balanced input
>> through two 68 ohm resistors and set the balance trimmer for each band
>
>> only to
> find
>> the radio pretty much deaf.
>
> Cecil,
> for doing the balance adjustment that's perfectly normal. I've found
> that to get a hearable signal for nulling I need to set the generator
> output several orders of magnitude greater. (Think about it, if the
> input balance was perfect you'd never hear ANY common mode signal).
>
> RF alignment is best done using the low-z balanced input with one side
> grounded (thus making it unbalanced) and connected directly to the
> signal generator output. Connecting a 50 ohm sig gen output to the hi-z
> unbalanced input will work of course but you're *really* loading down
> the front end tuned circuit and probably getting a much broader peak
> during its alignment.
>
> John
>
>
>
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