Mike,
We have done all those things to the generators and more. Even shielded the
ignition coils. Some of the noise is impulse noise that comes from the low
voltage input to the ignition coil. We can't do much about that, because
when we add even a small capacitor to this wire the generator becomes hard
to start. We have added more ground wires around the generators and that has
helped.
Will also add the radials you've suggested at the RX antenna feed point.
TKS and 73,
George
On Sat, 10 Aug 2024 16:21:23 -0700 Michael Tope wrote:
Hi George,
Is this noise you are hearing impulse noise from the generator ignition or
switching hash from the inverter electronics?
If it is ignition noise, shielding the spark plug wire fixed the problem for me:
http://www.dellroy.com/W4EF
's-Ham-Radio-Page/EU2000i/Ignition.htm
For inverter hash, a #31 toroid in series with the AC output works (trifilar
wound with THHN house wire). The idea was to keep the extension cord from
becoming an antenna or conducting noise current back to the rig chassis and
then along the coax to the antenna feed. I didn't even need to bother grounding
the generator, but in my case it was located a fair distance from the antenna:
http://www.dellroy.com/W4EF
's-Ham-Radio-Page/CQ160/2006.htm (scroll down to the photo of the generators
and gas cans). The filter in the Cantex box is mostly for higher bands (uses
#43 toroids), but I believe the unhoused toroid with the green THHN on it is a
#31 type.
If you need one at the antenna, 6 to 8 eight short radials 30 to 60 feet long
would probably make a decent counterpoise to provide a low impedance to shunt
against the series Z of a common-mode choke you are putting on your antenna
coax. I built one of those W8JI receiving 4 squares many years ago and I used
eight 60ft long radials for each vertical. That seemed to work very well (IIRC
that is what Tom recommended and I just followed his recipe). Critters chewed
the guy ropes and the vertical all fell down, but that's another story :-)
Hope that helps.
73, Mike W4EF...........
On 8/10/2024 12:00 PM, GEORGE WALLNER wrote:
Jim,We are using all of the cores you have given me. They help, but it is hard
to get a good ground at the top-end of the beach where the sand is very dry and
rocks prevent rods getting driven deep enough to reach moist ground. Yesterday,
a bit desperate, ran a 70 foot long GND wire to water, but I doubt it is doing
much good. We got chokes on most coax and control cables but without good GND
their effect is limited.
Using a single #31 2" core, how many turns of RG-6 do you think will give
decent choking effect? (I know, it depends on the GND and other loading factors.)TKS
for all the ferrite cores! Will let you know if we need more!
GW
On Sat, 10 Aug 2024 11:48:34 -0700 Jim Brown wrote:
Hi George,
Remind me where to send you more cores for your next trip. :)
In the meantime, try grounding the generator chassis (and/or grounding pin) to
a driven rod (or to screen/radials if you can't drive a rod). I've seen reports
that this can be effective with some generators on some bands.
73, Jim K9YC
Set up a DHDL RX antenna yesterday but it was picking up generator noise. Will
move it today to reduce noise.
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