[Hi-zreceivingarraydiscussions] lightning protection

[contact]

Hi Phil,

Please look at the Hi-Z 4-8PRO
http://www.hizantennas.com/4_8_pro_8_element_array.htm

It is 2 each 4 element arrays interleafed. This makes an 8 circle array,
with 8 directions every 45 degrees. Any questions glad to take them off
line.

73 Dick  KO7N

-----Original Message-----
From: hi-zreceivingarraydiscussions-bounces at hizantennas.com
[mailto:hi-zreceivingarraydiscussions-bounces at hizantennas.com] On Behalf Of
Phil W9IXX
Sent: Sunday, November 06, 2011 7:46 AM
To: Hi-Z Receiving Array Discussions; Phil
Subject: Re: [Hi-zreceivingarraydiscussions] lightning protection

Hi,

Will appreciate any information you can pass along on these changes to 
help correcting
these problems on my setup here in NC.  (4sq setup at NW, NE, SE, & SW)  
I am considering another 4sq setup
for shifting in relation to the original by 45deg.

Thanks again for the products and your concern in providing the best 
possible equipment.

73  Phil  W9IXX

On 10/22/2011 01:24, Lee K7TJR 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 w!
>   e 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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