Looked at the schematic of the PS (Astron RS-35M) and low and behold,
there was the ground wire for the negative terminal going right to the A/C mains
ground lug. Clipped the ground wire and re-assembled PS. Fired up Mini on a band
from DC to 22kc. Wow what a huge difference with nearly zero zip nada buzzsaw
sucker anymore. Solid VLF signals as well as quiet noise up the dial with Wahoo
signals thru the MW BC band (1.7mc). Now to make up a long patch cord that will
get a zillion turns on one of those big sucker toroids. That'll be tomorrow, I'm
beat...
A huge thanks Bill & to all the others who have told me about grounding
the feedline inside as well as outside and isolation transformers. The noise is
nearly gone now and I will get it down to nothing very soon.
----- Original Message -----
From: Bill Ashlock
Sent: Wednesday, March 01, 2006 12:06
AM
Subject: Re: [LW] Common Mode Noise on
Feedline...
Mike,
You would need a rather large bead/core that would allow
enough turns to have enough inductance to be effective. BTW check out the
reference that John D posted yesterday for another approach. The better the
ground under the probe the less the inductance required if you use the bead
approach. The location should be in the shack to prevent the lead-in from
becoming an antenna radiating junk to the probe.
Why not feed the DC on the probe side of a typical
1 to 1 core in the shack? Like I said last night the power supply must be
isolated from ground. The typical transformer feeding the rectifier in
that supply should provide this isolation, but you have to be sure the
house safety ground is not connected to the - side of the supply.
Bill
----- Original Message -----
From:
MIKE REID
Sent: Tuesday, February 28, 2006 10:16
PM
Subject: [LW] Common Mode Noise on
Feedline...
Would adding ferrite beads on the feedline on a active whip antenna
lessen the common mode noise issue? Where would the best place to add them
if this is a good idea? I was thinking right at the point where the ground
wire connection on the braid is.
Thank you,
Mike
WE0H
WD2XGI on the air
185.3026kc
EN35hj
