[Hi-zreceivingarraydiscussions] lightning protection

[Jo, YC0LOW]

Lee and Dick,
I look forward to seeing the document's mod on your web. The new 2 elements
rx array was working good for me while at /1 qth - a day after CQWW SSB
2011 contest. The /1 qth is also known as the 'lightning capital" :-)) and
we're shortly come to raining season (pse see Locator: *OI33TG94DX*
<http://aprs.fi/?addr=OI33TG94DX>Latitude: 6°43.76' S -  Longitude:
107°39.57' E)
Tnx es 73 de Jo, YC0LOW

On Sat, Oct 22, 2011 at 12:24 PM, Lee K7TJR <k7tjr at msn.com> wrote:

>   I believe we may have improved our systems ability to handle the energy
> from close lightning strikes. I know there are rumors out there and they
> are somewhat true. We have found 3 separate issues. One is that our
> transient diodes on the CTRL switching lines were being destroyed by
> induced currents. We have increased the size of those didoes and installed
> MOV devices across each one. So far knock on wood we have not seen any more
> damage to the diodes. The second item is if the system is powered and the
> relays in the HI-Z amps are open the FET devices and there clamping diodes
> can be damaged from static discharge. The only way to prevent this is to
> turn power off to the array during threatening storms. This has been a
> minimal problem. Yes, it is true we have lost a few FETs but what we have
> found is a third item where the Hi-Z amps were being destroyed by an
> induced transient on the 75 ohm output RG-6 line from the amp. We have
> designed some protection for this and so far we have been successful with
> no further damaged FETs directly attributable to this problem. We have
> modified all production to include these mods and have been installing them
> in any units that come in for service. One unfortunate individual that must
> live in the lightning capital of the world endured amp damage 3 times in as
> many weeks. Now after the mods we have heard of no more damage. Whew!
>  Any one needing more information can contact us directly as we are trying
> to document the mod procedure now so anyone experiencing probles can take
> advantage of the changes. This problem from our perspective has been a very
> small percentage of the units in the field. Contact us if you would like us
> to mod the units here. We are trying to figure out an equitable way to
> acoomplish this at a minimum cost to both parties. Again, not everyone will
> need these mods. We hope to get an application note up on the web soon with
> the change information also.
>  Thanks to every one for the tremendous support. You never know what we
> might come up with next!
> Lee  K7TJR
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