I'll throw in my 2-cents worth. I replaced my Butternut HF-6 with a 43-foot
vertical after doing a bunch of A/B testing between the two antennas. The
evaluation was all done on receive and on 160-15 meters (12-10 was closed
during the several weeks that I was doing the evaluation). For the 43-foot
antenna, I was using my Rohn 50-foot push-up mast insulated at the base and
pushed up to 43-feet. The Rohn was located alongside my house, and the
Butternut was located about 50 feet away on the corner of my small lot. Not
a perfect comparison, I'm sure. But not bad especially since I spent
several weeks comparing them. Anyway, I found that the 43-foot antenna
always provided a better receive signal on 20-160 meters. Often the
difference was significant (like an S-unit or more). Sometimes it was just
barely discernable. On 17- and 15-meters, the difference was negligable
between the antennas. Sometimes the Butternut was better, and sometimes the
43-foot antenna was better. But most of the time they were very similar.
Anyway, there is nothing like getting as much metal in the air as you can,
especially on the lower bands (the Butternut was only around 24-feet tall).
So, I permanently replaced the Butternut with a 43-foot antenna. I started
out using a unun, and had good results on 40, 30, and 20 meters. I don't
operate 60 meters as I'm pretty much a 100% CW op.
But I wanted to operate on 80 meters, and the SWR was terrible on this band.
Plus I decided I wanted to minimize any feedline loss on the higher bands
(the unun gives a compromise SWR on those bands, but still high enough that
I wanted to get away from it). So I decided to go with an auto-tuner at the
antenna base. Since I occasionally use an ALS-600 amplifier, I picked up a
CG-5000 autotuner from Array Solutions (the CG-5000 is spec's at 800 watts
pep). I've only been using it about a week now, but it has worked great for
me. Tuning on all bands took maybe two seconds the first time I transmitted
a carrier. But after that, the tuner snaps in the right L/C values in
milliseconds after it sees my signal.
The CG-5000 doesn't have the range to tune the 43-foot antenna on 160 meters
without additional base or top loading (I doubt that there are any
autotuners with the range necessary). When I get serious about 160 meters,
I'll either switch in some additional base inductance, or I'll turn the
antenna into an inverted-L to make it longer. But right now I'm happy with
operation on 80 meters and up.
For my small city lot with minimal backyard space (a pool takes up most of
the yard), this is a pretty good trade-off antenna system for me.
Phil - AD5X
TowerTalk mailing list