TopBand: Feeding a grounded tower

[Dean Fredriksen]

Steve Zettel wrote:

> If I go ahead and use unbroken EHS from tower to grounded guy anchors (the
> base of the tower is definetely grounded a la Ufer and ground rods), what
> is the best way to feed the tower for 160M, or is there a best way? Should
> I consider breaking each guy at least one place, and if so, where?

Steve,
It's been about 6 years since I did this, and with many antennas in between
-- I am admittedly short on details:

At my last QTH, I had 90' of Rohn45, guyed per Rohn specs, NO insulators in
the guy wires.  At the top were 105BA, 155BA and 205BA HyGain monobanders on
a 22' mast.  I had a 2M V2S side mounted at about 85'.  NO radials!

I was successfully able to match this system and use it on 160M.  I used RG8
as the gamma arm (the braid), and spaced it with PVC pipe at about 2' from
the tower.  I'm pretty sure I used an Omega match, not a gamma match, but I
made the capacitors out of RG-11 coax.  The SWR was around 1.3:1 ~ 1.5:1 at
about 1830 kHz.  I could cover 1800-1860 kHz or so, with SWR under 2:1.

Performance-wise, I worked over 90 countries in my first season of moderate
activity.  I was very competitive with local stations who were 160M
regulars.  I was using a modest station (TS440S & Clipperton-L amp, abt 600W
out).

No doubt that this antenna was inefficient.  Surely there were other
antennas I could have tried or improvements I could have made.  The  point
is, you asked if it could be done.  In this particular case yes, it could be
done.  It also worked relatively well.  The level of competition (like all
bands) continues to rise every year, so this may no longer be good enough to
compete in the pileups.  It WAS good enough to be heard on most continents
from my QTH (don't remember any activity from Antarctica back then :^)  ).

By the way, I did supplement this with some phased active receive antennas I
made.  I DID find it necessary to have some directional receive capability
to pull out "tough" ones.

73 & Good luck!
Dean, K4KR (ex-W8ZF)


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