I made the G5RV and I am receiving a lot of RF in the shack. I also have
installed infloor heating in many parts of the house and while trying to
tune, I trip the GFI thermostats, I believe that is coming from the G5RV.
Channel Jumper mentioned that before that it was a dirty transmitting
antenna. Now I am learning and installing ferrite rods (wrapping feeds from
my power supply aound the 3/8" x 6" Ferrite Rods. I am going to wrap about 5
rotations and tape them up. Seems practically all I can do. Which is better?
The ferrite bars to be wrapped around, at the ends of the feeds from power
supply or the RF chokes that simply clamp onto the cable, two halves coming
together? Any tips there are helpful.
Also, I landed an old Alpha Delta DX CC, now this was in the air for about
16 years and is very green. I want to rewire this antenna in hopes it
performs best. My question is about those coils. Do I have to find the
transformer wire which is smaller guage than the 12 ga wire I have to wind
those coils? Or can I simply replace those green tranformer wire coils with
the 12ga copper wire that I am using to replace all the legs of this fan
dipole? I am just basically duplicating the dipole's engineering, but not
the coils. I am wondering about those coils, do they need to have that
shalac tranformer smaller guage wire with two soldered connections or can it
be wound by the 12 ga copper wire and not have those two soldered
connections. One wire for the entier leg and have it wound around that coil
core.
What is the critical point here? The length of the wire or number of wraps
on the 1-1/4" tubing they used? Or are they the same anyway? Would 50 coils
of 12ga be the same length as what looks like 22ga? Same distance?
Thanks for the great discussions
73s
"W5DXP" wrote in message
...
On Sunday, October 28, 2012 6:18:58 PM UTC-5, Channel Jumper wrote:
But your dipole antenna needs to be resonant - 1/2 wavelength on the
lowest frequency you desire to operate on.
Like the G5RV that you dislike, if one removed the feedline from a 1/2WL
resonant center-fed dipole, it is no longer resonant. Resonance implies a
low resistive feedpoint impedance. The G5RV antenna system has a low
resistive impedance looking into the series matching section on 75m, 40m,
and 20m (also on 12m).
3/2WL dipole + 1/2WL feedline = resonance on 20m
3/4WL dipole + 1/4WL feedline = resonance on 40m
3/8WL dipole + 1/8WL feedline = resonance on 75m.
The (G5RV) ladder line is the matching network and it only works on 20
meters.
Here's technical proof that it also works on 75m and 40m.
http://www.w5dxp.com/G5RV.HTM
The Smith Chart SWR arc indicates how series section transformers really
work. The G5RV is a reasonably good antenna on 75m, 40m, 20m, and 12m. Not
so good on 15m and not good at all on 30m, 17m, and 10m. A ZS6BKW is a
better choice to obtain 17m and 10m but one loses 75m.
The G5RV antenna system is what it is. It is neither a gift from Heaven nor
a design straight from Hell.
--
73, Cecil, w5dxp.com