HELP....R5, R7 antenna
Allen Rees
antenna for good SWR. I have both and all bands have SWR > than 2.0:1. I
have set them up per factory instructions but have not had any luck.
James J Martin
: I need to know what is the best way to mount a cushcraft R7 or R5
: have set them up per factory instructions but have not had any luck.
Wonder what kind of feedline you are using? I have an R5 and have
had wonderful results with it. SWR and all.
Ken Albertson of Cushcraft sez that the antennas have to be installed
at least eight feet above anything. Any less than that and they are
subject to de-tuning.
It seems odd that you are unable to tune either antenna. Mine is
resonant where the traps say they are resonant. I am heard better
than I can hear. (I live in the city and the noise is ferocious here.)
If you still have problems after or if they are mounted at least eight
feet above anything, let me know. I will speak to Ken and come up
with some other suggestions.
BTW, how long have you had the antennas? But let me know what kind of
set up you are using...feedline (type, length, etc) where the antennas
are mounted and all that. We'll come up with something.
73 de wk1v
-jim-
kham
Martin) wrote:
Just a question. Here's Dave, AV7FV. Elsewhere in this forum there
is someone saying that his capacitors blew out with 100 Watts. Have you
had any problem like that? Also, I talked to someone at Cushcraft and
he did say 8 feet minimum, 12 feet optimum. How high is your R7 mounted
and do you have any problem with TVI, phone interference, etc. ? Do you
work DX with the R7?
Thanks, Dave
Jim Coleman
> In article <CzC5I...@world.std.com>, jjma...@world.std.com (James J
> Martin) wrote:
>
> > Allen Rees (ar...@uoknor.edu) wrote:
> > : I need to know what is the best way to mount a cushcraft R7 or R5
> > : antenna for good SWR. I have both and all bands have SWR > than 2.0:1. I
> > : have set them up per factory instructions but have not had any luck.
> >
Two comments about the R3-R5-R7 series.
1. It may seem obvious but with two different antennas in this series,
I've found problems with the connection where the tip inserts in the next
lower element. A good dose of steel wool and conducting paste fixes the
problem. In one case I had to open the slot a little larger with a hacksaw
to get the hose clamp to tighten down enough.
2. The "optimum" height for these antennas depends on the band. Also the
quality of the ground does indeed play a role. Look in the ARRL antenna
book for halfwave verticals height above ground and you can get an idea of
the trends. For many years I had good luck with an R3 with the base at
about 20 ft above ground at the edge of the roof.
Good luck,
Jim KA6A/9
--
James J. Coleman
Microelectronics Laboratory
University of Illinois
Urbana, IL 61801
au...@orion.alaska.edu
I had similar problems with my cushcraft r7. I mounted it at ground level and
could not get swrs down. So, I mounted it up on a 10 ft 1.25 inch steel pipe.
All dimensions were consistent with the manual. I was able to get the swrs to
match the specs and better!
Make sure when you elevate the antenna that it is balanced and the larger
pieces of tubing bear most of the antenna weight. They can really sway in the
wind if not properly matched. Also, rain and snow can detune the antenna, so
don't tweak it on a wet day!