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

[Dave]

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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