On 10/30/2012 8:23 AM, W5DXP wrote:
On Monday, October 29, 2012 2:45:22 PM UTC-5, Boomer wrote:
I still think you should do this yourself. Just ABing the receiver is an
important test. G5RVs have a reputation that I cannot personally confirm
of being noisy. I do know for certain that some antennas produce more
noise than others.

I've spent many years experimenting with G5RVs including field strength measurements vs a dipole and a vertical. When someone has a problem with a G5RV on 75m, it is invariably because good engineering practice was not used in that particular design and installation. An inverted-V at 15 feet with no choke/balun and twinlead taped to a conductive pole and/or laying on the ground is certainly not going to work very well. With both antennas properly designed and installed, it is difficult to tell the difference at resonance on 75m. However, the G5RV is fairly non-functional on 30m, 17m, 15m, and 10m. 17m and 10m are necessities for me and that's why I don't use one. I bought a G5RV in the late 80's expecting it to live up to its all-HF band advertising and I was disappointed. That's when I went to my no-tuner all-HF-band 130' dipole.

http://www.w5dxp.com/notuner.htm

Like any dipole where the two dipole elements are DC isolated from each other, the G5RV is susceptible to precipitation static. An RF choke across the conductors will solve that problem.


Maybe those who chose a G5RV to buy something cheap and easy also then
erect it poorly. I have seen a G5RV erected in my town here. It looks
awful. It works just as well. I talked to another ham a few days ago on
40 meters. His G5RV was mounted at 10 feet. Some guys actually wind
their window line into a coil.

I also saw another antenna in town. It was supposedly a 75 meter zepp.
It had 6 feet of window line and then a 60 of wire wound around a single
tree. I am always amazed at the lack of planning and engineering that go
into some antenna installations.

These guys will never have a good signal and probably never know why.
Most will not ask for help because they already know that their antenna
is great. I don't know why some hams will have their self-esteem tied up
in their rigs and antennas. I mostly use an Icom 751A and I know it is
not the best rig in the world. It is old and needs repair once in a
while. My 75 meter loop at 35 feet of height is not the best antenna in
the world, but it is the best I can do for height given my trees and
property. However, I listened to someone who knew more about antennas
than myself and he convinced me to change my window line feed to open
wire. I got a huge benefit in performance. It does not make sense to me
that a plastic dialectric is so much worse than air. Maybe it is the
change from 450 ohms to 600. But boy did that antenna start working better.

Michael