[R-390] Synthesizer Phase Noise

[Lester Veenstra]

Actually, the gain of those rotating LPA's is rotten. Now a nice sterba
curtain or rhombic is another matter.

 
Lester B Veenstra  MØYCM K1YCM
lester at veenstras.com
m0ycm at veenstras.com
k1ycm at veenstras.com
 
 
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-----Original Message-----
From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
On Behalf Of rbethman
Sent: Sunday, August 16, 2009 9:55 PM
To: r-390 at mailman.qth.net
Cc: Tisha Hayes
Subject: Re: [R-390] Synthesizer Phase Noise

Tisha and others have pointed out the noise levels inherent with the 
external synthesizer.

However, we have to remember that these were used with antenna systems 
that we could only dream and drool over.

One particular receiver site of infamy, isn't very far from me.  I do 
remember when it was still up and running.  When you drove up the road 
to get to the Guarded entrance, you drove for at least a quarter mile 
along a massive curtain array.  That was only ONE of the VERY large 
number of antennas that were visible from the road.  The entrance road 
to the actual road, even had a firing range situated between the curtain 
systems and the Guarded entrance.

Considering that this was a Rifle range, you "may" begin to get a feel.  
Just as you came to the guard, you could observe three or four RLPs, 
(Rotating Log Periodics), that were about 70 foot up in the air, and 
from the rear elements, 3MHZ was certainly within reason.

When you use an antenna system(s) like this, noise becomes a non-issue.  
The gain of these systems had to be unreal.  But, that is what they were 
there for.  Simply to listen, record, store, and pass on to those places 
with initials.

BTW, those curtain arrays were strung on poles the tops of which were 
WELL above the top of ANY power pole in the vicinity.  They were 
obviously Class 1 poles!

Bob - N0DGN

Tisha Hayes wrote:
> I had my doubts about the capabilities of the synthesizer just by looking
at
> the block diagram and "imagineering" how they would do it. It is not
> surprising to hear that phase noise was a problem.
>
> Someone could create a similarly functioning external synthesizer for the
> R-390A using a variety of techniques with digital IC's by why bother?
>
> Tisha
>   

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