Hi !

Jack PE2JV wrote:

Hello,
I recently obtained a almost new GPA-50 hf vertical. Now before
i am placing it in a mast/roof there may be fellow hams with tips
about weather proofing or adjusted radials etc. If any please let
me know. Thanks.
Jack. PE2JV.

I am using the GPA-50 since about two years and i am very pleased with it,
my landlord does not allow to set up a beam and i do not have the space to
set up wire dipoles.
The GPA-50 covers 10,15,20,40 and 80 meters but not the WARC bands.
On 10,15 and 20 it uses the included 1/4 wave counterpoises, on 40 the
included dipole, shortened with the loading coils and on 80 you need to set
up a counterpoise yourself i.e. metal roof or large sheet of chicken wire,
the larger the counterpoise on 80 the better.
I have the GPA-50 on a two meter mast at the courner of my penthouse patio,
the 1/4 wave radials running to the edge of the roof at an angle of 90
degrees, so i can walk/use the patio beneath them. SWR on 10 to 20 meters
is abt. 1:1,2 a little higher at the edges of the bands. I did not cut the
radials at all.
The 40 meter dipole is a little tricky since it tends to get "disturbed" by
metal close by i.e. metal roof. After setting it up the SWR was infinite.
I got it to 1:3 by cutting small pieces from both legs similar. However
since i have some metal close by i did not get it below 1:3 but the built
in tuner of my radio takes care of that without any problems. I did not
expect the dipole working well, however at nighttime and good conditions i
am able to work JA with 50 watts from here (North Germany) in CW.
If you have a metal roof try to connect that as counterpoise on 80 otherwise
you will have to fiddle with chicken wire or many unbalanced wire
counterpoises.
I connected a copper rail running arround the house at the floor of my patio
and it works quite well on 80 meters. I tuned the antenna to SWR 1:1 at the
middle of the band by adjusting the tip at the top of the antenna. However
the range of "good" SWR on 80 is very small so i have to use the tuner of
the radio again when QSY'ing on the 80 meter band.
BTW i am located in the 5th floor of the house so the location of the GPA-50
is quite high from the ground.
The antenna gives my quite good results running barefoot only (100 Watts) on
DX and with 10 Watts from my IC-703 i can work Europe with reports ranging
from S7 to S9+ on 20 meters if conditions are not too bad.

73s and gl, thomas [DF1HX]
--
Thomas Krull [DF1HX]
gpg (GnuPG) 1.2.4 0x01EC2546