I've long been a fan of the EFHW for portable operation, but I've always
used a tuner. There seems to be a lot of aversion to tuners. If you can
get over that, many possibilities open up. A simple L-network will match
the EFHW. (Though not the ones built into radios.)
The EFHW is easily modeled with EZNEC, etc., and I think the results are
quite accurate. Beware, however, that antennas like the EFHW-8010 are
multiples of a half wave on all but the lowest band, and their pattern
will behave accordingly. On the lowest band, it's much like an inverted
V, and has the advantage that, even though the feedpoint is near the
ground, the maximum current is at the apex, where it radiates most
effectively. I've used a 40 meter EFHW on 40 and 20 with good results
for portable operation.
Another wire antenna I've had good success with over the years is a 100
foot wire center fed with 300 Ohm window line. Like the EFHW, it has the
advantage of not needing a good ground or counterpoise, so it's a good
choice for an apartment, etc. not on the ground floor. It requires,
however, a truly balanced tuner, not one with a balun transformer at the
output. I used a homebrew link-coupled tuner I built over 50 years ago.
There is one MFJ tuner that's truly balanced, but I haven't used it.
73,
Scott K9MA
On 7/1/2019 10:18, john@kk9a.com wrote:
It needs no tuner or counterpoise and it has great eham reviews! How
does this work?
John KK9A
David Gilbert xdavid at cis-broadband.com
The EFHW-8010 gets rave reviews, but I'm fundamentally suspicious of any
antenna that covers that wide a range without tuning. There have to be
losses somewhere to get that.
Those same reviews also claim similar results for installations 6 feet
off the ground versus 60 feet. That also doesn't make sense given the
effect that ground typically has on the feedpoint of a horizontally
polarized antenna without a lot of loss.
I couldn't find anyone who had done a real time A vs. B comparison
against, for example, a center fed dipole at 40 feet on 20 meters. I'm
not saying that the EFHW-8010 isn't a practical single antenna for a
given set of constraints, but I'd bet a lot of money that you could do
better with a collection of other properly chosen wire antennas if you
have the space (presumably you do if you can put up a 130' long
EFHW-8010) and some decent trees.
And if your ground conductivity isn't too bad, I'd even consider an
Inverted-L or two with VOR-type counterpoises before I'd rely on
something that physically shouldn't work without a lot of loss ...
especially if the distance from the antenna to the shack is short enough
that you could use a tuner for operation on multiple bands without a lot
of feedline loss due to SWR.
My two cents worth ...
73,
Dave AB7E
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Scott K9MA
k9ma@sdellington.us
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