[Premium-Rx] Lightning hitting your Premium RX

[Cecil Acuff]

Gary,

        I looked over your pictures.  Looks great.  Typical with what I see 
at most of the commercial tower sites I frequent.  The question remains as 
to whether you have your house electrical ground tied to your tower 
grounding system.  It appears you do by virtue of the AC power protectors 
plugging into AC outlets in your shack.  Curious why the ground runs with 
the rods went out at angles away from the shack.  Common wisdom in the 
commercial tower business is to create a ring around the building being 
protected.  May have been inconvenient to circle the house...

What is the lower end frequency of the Coax protectors?  I typically use 
Polyphasor systems at work but that is for VHF/UHF stuff.  I'm not sure 
their stuff goes down to LF or not.  Seems protecting to 500Khz or even to 
1.8 Mhz is a little more difficult.

You've done what most folks are unwilling to do...that is to spend as much 
on your protection systems as a new high end transceiver costs.   Should be 
well protected!

What did your final ground point impedance end up being?

Now you need a strike counter on the tower.....HA!

Thanks for the info...

Cecil Acuff
Gulf Coast of MS.  (pretty near the lightning capitol of the US)

----- Original Message ----- 
From: "Gary Mitchelson - N3JPU" <n3jpu at speakeasy.net>
To: "'Premium-Rx (E-mail)'" <premium-rx at ml.skirrow.org>
Sent: Tuesday, April 05, 2005 2:31 PM
Subject: RE: [Premium-Rx] Lightning hitting your Premium RX


I've got all my radios, including my premium RXs, grounded to a SPG and use
ICE arrestors on the feedlines (ICE suppressors will also drain off static
build-up, they block as well as shunt), all the AC into the shack, and all
rotor and remote antenna switch control lines. This then gets grounded to an
extensive Cadwelded groundrod array. All the feedlines are also grounded at
the tower base and then routed through a 2" grounded EMT conduit.

Have some pictures and links on my website.

Gary Mitchelson
N3JPU Montgomery Co. MD  FM19
http://www.mitchelson.org/

-----Original Message-----
From: premium-rx-bounces at ml.skirrow.org
[mailto:premium-rx-bounces at ml.skirrow.org] On Behalf Of Carcia, Francis A HS
Sent: Tuesday, April 05, 2005 14:42
To: Premium-Rx (E-mail)
Subject: [Premium-Rx] Lightning hitting your Premium RX


 The bottom line for lightning strikes is you have to provide a low Z to
ground to pass a lot of current or you will generate a lot of voltage.
(Transfer Z). I just did some interesting testing with poorly shielded wire
and observed a lot of induced voltage on the center conductor due to shield
resistance. Ground systems that are not properly bonded to a single point
ground can generate very large voltage offsets. A couple days playing with
our big pulse generator and all the NEC stuff made sense. I remove the
antenna coax with a bird switch when not in the shack. Then I take the coax
off the splitter just in case. no path is much better than a poor path.  fc


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