I built a K9AY loop that uses a mini-circuits 9:1 DIP matching transformer.
When first constructed, I blew out several of them whenever I operated QRO.
Being unsatisfied with the performance of the transformers I wound myself on
binocular cores with relatively heavy wire (I know now what I was doing wrong)
I slapped a couple of Si signal diodes across the primary winding of the mini
circuits device in desperation. It worked. I do not notice anything odd about
the Rx performance. In fact, the antenna has wonderful S/N on bands even where
it is no longer directional (40m and 30m) compared to the vertical transmit
antenna.
Al
AB2ZY
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Pete
Smith N4ZR
Sent: Sunday, January 13, 2013 3:58 PM
To: TowerTalk
Subject: [TowerTalk] Elementary Rx protection question
Do back-to-back diodes across a receiving antenna degrade receiver performance
before they begin to conduct? what I'm considering is back-to-back series
strings of diodes to limit RF voltage at the front end of an SDR. My working
assumption is that the conduction threshold could be set below the damage level
but above the ADC clipping level, but if it affects performance before the ADC
clips then that's no good.
--
73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.
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