At 10:07 21/03/97 -0800, you wrote:
>I've been using a roof mounted HF6V vertical (at about 16') for the
>past 5 years with reasonable results. I'm currently looking into putting
>up a tower, but in the meantime I'm curious if a roof mounted beam
>(say a Force C3/C4 or Cushcraft A4) at around 20' - 25' would do any
>better than the vertical.
>I know the rule of thumb with beams is "higher is better", but what is
>the minimum height at which I can expect reasonable results? or at
>least better results than the vertical?
> 73 de Doug, N6RT
> Doug Brandon http://www.kaiwan.com/~dab firstname.lastname@example.org
I am not an antenna specialist but I can tell you the experience I had. Two
years ago I replaced a 3 el. tribander (because it was quite old) for a
Cushcraft R4 (very similar to the R5). What a mistake Doug! My noise
increased a lot and I was not able to listen the DX anymore. Local ham
friends had much more reception with a single wire dipole. I recall a guy
from Africa giving me the report of 59+ and I was almost not listening to him.
I tried the 1996 ARRL DX SSB with very poor results, my neighbor PY1LI with
a KT34A (at 25 ft over the building's roof) had a pile-up on his frequency
and I was really upset with my poor station. I had to call several times
(using 1KW on 20) to have an answer. I gave up the contest and started to
think in a improvement for my station. My budget was low and a local ham was
selling an all brand new Mosley TA-33 (3 el. triband yagi) for a good price.
I was afraid to raise it for the same reason you mentioned, I couldn't raise
the antenna too much. I was thinking what kind of improvement I would have
because when I replaced my old 3 el. Yagi I was coming back to Ham radio
dxing after almost 3 years QRT. I had no parameters anymore, this time the
susnspot number was pretty low. I did anyway! I raised the beam about 35 ft
over the ground and about 20 ft over the concrete roof. And what improvement
I had! I was able to work 99 countries in a single contest (CQ WW SSB 1996).
But propagation was good during that contest, I needed another one to check
the real improvement. I tried the 1996 CQ WW CW just for fun and worked
Vietam, Cambodia, American Samoa among other good new ones on 15 meters. I
forgot to tell you. The R4 was still there and I couldn't listen to 80% of
the stations I worked in both contests.
I don't like verticals, with the exception you have an efficient receiving
system. If I were you I would go for the beam.
Now I am thinking about replacing my TA-33 for a better beam but the change
will be very expensive. I almost bought a used TH7DX but I will have
problems to import the parts damaged by the time and weather.
73 and GL,
Carlos - PY1CAS
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