Towertalk
[Top] [All Lists]

[TowerTalk] YCCC 9 circle preamp failure test

To: "tower and HF Antenna Construction Topics." <towertalk@contesting.com>
Subject: [TowerTalk] YCCC 9 circle preamp failure test
From: VE6WZ_Steve <ve6wz@shaw.ca>
Date: Tue, 24 Sep 2019 12:09:41 -0600
List-post: <mailto:towertalk@contesting.com>
Yesterday I decided to measure the actual voltage at base of my short HI-Z 
verticals while I transmitted on the TX array.

Since I first posted about the coupling capacitor failures in these units, I 
have received private emails form 4 others with the same problem.

My question is what has caused these failures? Is it a lightning event,  is it 
high-potential wind static on the vertical elements or is it from TX RF 
overload.

TX overload seemed possible at my location because my array is less that 100’ 
from the TX antenna.  I built a diode detector probe and in the field measured 
the actual voltage when TX.  The results indicate at most I see 50 v at the 
pre-amp.  The coupling caps are 63v rated units.  This would indicate that RF 
overload is not the cause, but I would really like thoughts and opinions from 
others.
I have redesigned the amps to include a relay to short out the antenna when not 
powered up, so I feel I am protected from any cause.

Here is a link to a YouTube video that shows the test set-up and the actual 
measurements I made in the field.  I also talk about using gas discharge tubes 
as a remedy.

https://youtu.be/TmM_YnLob68 <https://youtu.be/TmM_YnLob68>

73, de steve ve6wz
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
<Prev in Thread] Current Thread [Next in Thread>