[Elecraft] 80m KPA1500 High reflected power problems **SOLVED!**

[Peter Dougherty]

This summer I intend to get an entry panel from KF7P, along with a ton of
arrestors inside for everything. 

The real difficult part will be getting all the cables that now enter the
house at base of the tower and across the crawl space to instead run under
the deck. I'm to tall, too fat, and too creaky to slither under there over
rocks and gravel to run a half-dozen or more cables. I should consider
hiring someone to attach some 4" conduit with sweeps under there. It would
make the problem go away quickly. 

 - pjd

-----Original Message-----
From: elecraft-bounces at mailman.qth.net <elecraft-bounces at mailman.qth.net> On
Behalf Of Dave
Sent: Monday, March 11, 2019 8:52 PM
Cc: Reflector Elecraft <elecraft at mailman.qth.net>
Subject: Re: [Elecraft] 80m KPA1500 High reflected power problems
**SOLVED!**

Pete,

I had a similar problemon lower end of 80 meters. Fix for me was to ground
outer jacket of all antenna cables where they enter the house. This
eliminated common mode current coming into the shack on a second coax.

Check your RX antenna cable, which does not go through the RCS-12.

Dave wo2x

Sent from my iPad

> On Mar 11, 2019, at 6:13 PM, Jim Brown <jim at audiosystemsgroup.com> wrote:
> 
>> On 3/11/2019 1:40 PM, Peter Dougherty wrote:
>> I've got my bonding about as good as I can get it for the moment, 
>> although I'm probably going to do some improvements this year. The 
>> lightning arrestors are built in to the RCS-12 antenna switchbox 
>> (RCS-12L with the gas discharge tubes), and everything's bonded at the
base of the tower.
> The function of GDTs is to offer some protection of equipment in the event
of a strike. To do that, they must be close to the equipment, not at the
tower. Lightning can induce a lot of current on the coax between the tower
and the shack. I suggest that you add arrestors (including that vertical you
use for RX) where all of your coax enters the shack, bond them to your
rod(s), and to the shack bonding.  That's probably the missing bonding that
I suspected! Also, what about bonding to the power entry panel?
>> There's
>> a single feedline coming inside from that tower-mounted switchbox. 
>> Each piece of radio gear and the computer inside is bonded by 1" 
>> braid going to a copper bus. LAN and voice line comms are not, 
>> however the connection from the pole is fiber, not copper so that's not
likely a problem.
> Agreed.
>> The copper bus
>> inside is bonded to a ground rod outside the shack, which in turn is 
>> bonded to the tower ground system.
>> 
>> The deficiency is that the copper bus is not grounded to the same 
>> point as the tower, since the tower is about 50 feet away from the shack.
> This distance is borderline for bonding to the house.
>> I guess I
>> could run a 50 or 60' run of 2" strapping from the desk, through the 
>> floor, across the crawlspace, and out the conduit to the tower, but I 
>> suspect that might be more a hindrance than a help, quite honestly.
> 
> Agreed.
> 
> My shack is in what used to be a "mother-in-law" apartment of a detached
garage. I have a rod where power enters that building (fed from the house),
a half-perimeter #6 running around the building to the shack, where there
are five driven rods, all exposed to rainfall, and three rods along that
perimeter ground. The coax entry panels (added a second one when the first
filled up) on the wall of the shack are bonded down to the rods and up to
the ground bus for the equipment. They're also bonded to steel conduit that
runs back to the entry panel.
> 
> 73, Jim K9YC
> 
> 
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