Unless the feedline is up in the air, I can't imagine you need anything at
all except perhaps some decoupling to prevent common mode noise from
reaching the vertical.
I'm sure even a minimal impedance would be more than enough.
Decoupling is mostly a complex issue with seriously truncated, sparse, or
elevated systems. Those systems have huge electric fields around the
counterpoise. R7 verticals (and similar) are a good example. They will melt
most common mode chokes, and I've seen them cause an arc through the coaxial
feedline insulation to ground.
----- Original Message -----
From: "LY2KZ" <vytenis.sciucka@gmail.com>
To: "Tom W8JI" <w8ji@w8ji.com>
Cc: <topband@contesting.com>
Sent: Tuesday, September 04, 2012 12:10 PM
Subject: Re: Topband: Air core chokes for 160m
Hi Tom
I (we) have 21m height mast with two sloping ~17m length top wires. There
are 25 radials each about 25m long. The ground is good. Wetland or fresh
water in early spring.
http://rk.vdu.lt/images/stories/ly2fn/P2260028_600_x_450.jpg Its
February, CQWW160 SSB 2012
Feedline is long. ~150..200m RG-213. Measured antenna Zin=23+j4
Vytenis
ly2kz @ly2w
On 2012.09.04 18:30, Tom W8JI wrote:
What ground system, feedline routing, and antenna do you have? Most of
the problems, and the acceptable choice of decoupling, would depend
feedline routing and the particular counterpoise or ground system.
73 Tom
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UR RST IS ... ... ..9 QSB QSB - hw? BK
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