[RFI] stealth RFI
aa6dx at pacbell.net
Sun Jun 15 15:32:04 EDT 2003
Another fine mess you have got us into, Ollie!
----- Original Message -----
From: "Ted Bohrer" <N7QY at arrl.net>
To: <rfi at contesting.com>
Sent: Sunday, June 15, 2003 2:13 PM
Subject: [RFI] stealth RFI
> Well, All
> My buddy has a RFI problem in the TV and home stereo. Here's the
> (He has the Icom 756 Pro II, Icom linear and tuner, GAP Challenger)
> THE SETUP TO DETERMINE EXTENT OF RFI PROBLEM-
> "I turned on TV, sat the wife down, asked what channel was the worst,
> and did a baseline test with Icom linear on (500w), voice and CW.
> The TV screen does a little herringbone on key down full 500w and the
> speakers mumble on SSB, worse with processor on."
> INTENTED SOLUTION-
> "So I tear out my grounding harness made of 1.5 inch braid bus bar
> and 0.5 inch braid straps going to each piece of equipment and
> replace it with individual braid lines all going to the back of the
> Icom tuner, and the tuner uses #8 ground wire on a 10' run to a 8'
> ground rod just outside the shack. Then I installed a Radio Works
> T-4G grounded Line Isolator at the Gap Challenger antenna hooking the
> isolator ground strap to the 10' ground rod at the foot of the
> Gap.Then back in the shack I put T-4 Isolators (The Radio Works:
> http://www.radioworks.com/clitop.html) between the Icom 756 Pro II
> and the Icom linear and another T-4 Isolator between the linear and
> the tuner. So after much cussing, cutting of finger on who knows
> what, writhing in dust behind the rigs and multiple contortions
> working on the back of equipment from the front, I declare the
> project done and RFI hereby gone."
> THE TEST-
> "So I sit the wife down in front of the TV again and fire off the rig
> to show her how OUR $100.00+ worth of Isolators and ground rods had
> banished the RFI. So I lay on the key while we are both watching the
> screen . . . . . and.....
> BIG blankety blank 4 INCH WIDE DIAGONAL BARS GO MARCHING ACROSS THE
> SCREEN . . . 5 X 9 !!!
> much more blankety blank, blankety blank. . . It is easy 3 times
> worse than before I installed the line isolators!!!
> So do I still have RF in the shack? Darned if I know, how am I going
> to tell? Do I still have RFI on the TV? Oh yeah, big time.
> Maybe, just maybe the RF on the coax is now gone, and there is less
> RF in shack, but the result was more power to the antenna or a
> different pattern which is pumping more RF into the house wiring
> which is really the way the RF was getting into the system in the
> first place, thus more RFI at the TV. I still have 4 split ferrite
> squares that I was going to put on the 110v power cords of the TV and
> the Tuner box. I almost hate to do it cause I have this sinking
> feeling it will make it even worse."
> SO THERE WE HAVE THE CHALLENGE-
> Can anyone make any suggestions for us?
> Thanks and 73,
> Ted N7QY
> "What could possibly go wrong?" Laurel and Hardy
> RFI mailing list
> RFI at contesting.com
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