There is nothing better than "doing it right"! Great job Phil.
73 Bob, K4TAX
On 11/22/2015 7:59 PM, Phil Anderson wrote:
Hi Jan,
I'm guessing, as several others have discussed using a balun at the
base of the vertical, that the problem is interference running on the
outside of the coax feed. I'm using a STEPPir vertical for 40 through
10. I tried several baluns with no satisfying success. I then decided
to build a SPGS (single point grounding system) on the outer wall next
to my shack in the back yard. My SPGS is enclosed by DX Engineering's
"Grounding and Utility Encloser," (DXE-UP-2P) and I installed in that
three ALPHA-DELTA lightning arrest (surge protectors) (for three
different antennas, one being a Beverage), and a CONTROL LINE
PROTECTOR, (DXE-IS-RCT), that protects my Steppir vertical antenna
control system. In addition to that I ran #6 copper to the house
utility box ground (from the antenna ground) AND (perhaps most
important) ran three ground rods spread out (at twice the length of
the 8' rods) and connected all of that to the vertical grounding plate
(of the SPGS box) The important thing is that I did not use #6 wire
from the vertical to the SGPS box; instead, I used 2 inch wide copper
strip that is bonded to the rods with copper plates and connections at
each end of the run. The 2 inch copper strip is then attached to the
SPGS 14 x 14 plate (with another ground rod) just outside the house.
THE THEORY IS THAT THE WIDE STRAP PROVIDES FOR A VERY LOW RF IMPEDANCE
AT THE FREQUENCY OF OPERATION. This substantially shunts off any
interference returning on the outside braid of the coax from the
vertical. In addition on the inside (at station) I ran a strip of the
2 inch copper along the back of the station table and then smaller
braided strap from the copper strip to each major piece of equipment
on the station (a reverse V from the SPGS if you will) : DELL OPTIPLEX
COMPUTER (station computer), two 19 in flat screens, my fully loaded
Elecraft K3 with P3 WinkeyerUSB, and Astron switching supply.
The result was immediately apparent: the spikes I had been receiving
that were spaced up and down the 40 through 20 bands as noted on the
P3 panadapter where now completely gone. An added surprise was that
the noise floor even went down a bit (and I live two blocks from a
shopping mall!). Prior to this large station upgrade - inside and
outside the house - I would even see interference on the 19 inch
screens - that is now gone too.
If you like I can send you more detail on what I did, including
pictures. I've only been testing it for a week so may find some
glitches....but so far very happy.
73 and good luck. Phil Anderson, W0XI, Lawrence, KS
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