[ICOM] Icom 756 and ESD

[Roger (K8RI)]

On 5/4/2012 2:12 PM, John G. wrote:
> Last month there was quite a discussion on this reflector about the Icom 756PRO series, 746PRO, and 703 being damaged by ESD, and made it sound like they are overly sensitive to this phenomenon.  Is the 756 original also overly succeptable to static discharges, or did the problem start with later models?

I have to wonder if the ESD problem isn't as much an installation 
problem as it is rig oriented.
As I mentioned in the previous thread, after putting the 100 foot 45 G 
up with a 2" DOM mast extending close to 30 feet above the tower and 
about another 20 feet down into the tower to the rotator, the thing 
seemed like a lightning magnet. The 90 foot tower it replaced had been 
stuck twice in roughly 20 years (give or take) with one computer wiped 
out and the front end taken out of a Kenwood 221.  According to visual 
count/verification the tower/antennas/mast took 17 direct hits or just 
under 3 per summer.  It took no hits the last three summers, or at least 
none anyone saw and there no simultaneous Flash/Bang episodes.  Nothing 
has been damaged since the ground system was installed.  Good design? 
Luck? who knows? The next storm could wipe out everything as there is no 
system that comes with a  100% guarantee to protect the station.

Until I set the rig up in the shop about 3 years ago, my 756 Pro was 
connected to the TH-3 tribander at 100 feet, pretty much 24 X 7.  I had 
the rig on my desk with a *mass* of wires behind the desk that made it 
quite difficult to disconnect anything quickly.  So it's likely the 756 
Pro was connected to the tribander when it took those hits.    The photo 
on QRZ shows the set up in here.

The tower and station grounding system is fairly elaborate network of 32 
or 33 eight foot ground rods CadWelded (TM) to over 600 feet of bare #2. 
The coax cables all have their shields grounded at the top and bottom of 
the tower and again where they enter the house and now shop. They also 
go through PolyPhasers  at the grounded bulkhead where the coax enters 
the house.  There were 5 coax cables for the station, 2 RG6 for the TV 
antennas, and two RG 6 for the satellite dish, before I started the 
maintenance on the antennas.30' of 2" DOM with 1/4" wall is just too 
long, but there was no damage to anything in the house from lightning.

73

Roger (K8RI)
>
> 73 John AF5CC
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