Topband: Hardening the 8 Circle Receiving Array

[Lloyd - N9LB]

Hello Mark!

I have the YCCC Hi-Z spaced at the compromised 60 ft. parameters to improve
80 & 40m operation - that was a mistake!  
Go with the recommended 160m spacing.  I plan to modify my Hi-Z for optimum
160m operation ASAP.

Since the Hi-Z sits on the ground, putting it out in the fall and bringing
it back in every spring is not a big deal.  It only takes a couple of hours.
Lightning protection is not usually an issue in the colder months, although
we do get "Thunder-Snow" occasionally, but so far no damage from that.

For static build-up protection, which is a real problem in the winter
months, I installed 100K 1w carbon resistors bridging the inputs to ground.

This will be the 4th or 5th year for my Hi-Z array.  I also have BOGs and
two types of RX loop antennas.  

Lloyd - N9LB

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Lee.
KX4TT via Topband
Sent: Friday, October 18, 2019 8:16 AM
To: 'Mark Robinson' <markrob at mindspring.com>; topband at contesting.com
Subject: Re: Topband: Hardening the 8 Circle Receiving Array

GM Mark,
The easiest way to think of this is Diodes = Detectors; with high-powered RF
around, that becomes a Bad Idea. A possible alternative MAY be high-value
resistors to ground across the front end of the preamps. A representative
value would be 10 MΩ or greater, and I would match the resistances to ±1%.
However, Tim's warning still applies in that this mod may damage the
performance of the array. I only mention it because I've used it with kite
and balloon antennas to drain off static discharge, and it may prove useful
here. 

73 de Lee KX4TT


-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Tim Duffy


Hello Mark:

Installing diodes can cause severe problems with nearby broadcast stations.

During the summer months and lightning months I remove my preamps from the
antenna elements to protect them. 
I am now just getting them installed tomorrow morning to prepare for the
Fall Stew contest on Saturday.

Be careful making modifications that may hurt your array performance

73
Tim K3LR

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Mark
Robinson

I  have the DX Engineering 8 circle receiving array sized for 80/160m . 
It has been a fantastic performer but I have suffered damage to the active
antenna amplifiers on two separate occasions due to nearby lightning
strikes.

I am looking at a way to protect these amplifiers.  I was wondering if I can
add a pair or  dual series pair (4 diodes in total) of back to back diodes -
say 1N3600,  across the input to ground terminals on each amplifier.  Will
this affect the performance of the array in any way ?

73 Mark N1UK

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