I’ve had good luck using fast zener diodes in series with ordinary
small silicon diodes (eg 1n914). The zener keeps the signal diode out
of the antenna circuit until the zener breakdown voltage, say 10V or
so, is reached.
73,
Jim w8zr
Sent from my iPhone
> On Oct 18, 2019, at 7:16 AM, Lee. KX4TT via Topband <topband@contesting.com>
> wrote:
>
> 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@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@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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