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RFI issues solved by accident.

FISHULA X Member ✭✭
edited June 2019 in New Ideas
 A few years back I stumbled on a trusty trick. I have an in line line isolator. I always had all kinds of RF when I transmitted. I came through my speakers and I even messed up the image on my monitor. It was bad. And it got much worse when running my Amp. It was even shutting down my computer. Here is some helpful info. I tried everything from grounding to snap on beads on everything. This is what I stumbled on by accident and may fix your RF issues in your shack. My isolator has ferrite beads inside and is about 1 ft long and is shaped like a tube with female coax ends . I took the line isolator in my hands just as if I was water skying. I held it with both hands with the coax attached to the left and right.  Then I took it and like I say I held it like a water ski handle and I twisted it hand over hand  a few times and let the coax twist with it naturally and then tucked it away under my desk. I keyed my radio and talked and noticed  it got much better. I then pulled it back out and twisted it one more time. No more RF, None, completely gone, even with the amp on. Now ever since I learned that trick it has always worked 100 percent for me.  This worked with my Flex 5000 and now with my 6300. It was an accident and it worked like a charm.  Hope this helps you. Try it, 


  • mikeatthebeach .
    mikeatthebeach . Member ✭✭
    edited June 2019
    Well this means your line isolator did not have Enough isolation I take two or three FT-240-31 Ferrite Dounut Course and loop 3 to 4 turns of the 50ohm Coax This adds to the isolation of Keeping RF currents from traveling down the Coax line to get into the HF Rig even with Full power 1.5Kw onto the feed line ! Not all line isolators are the same Palomar Engineering or Balun Solutions Make very good 50ohm RF line isolators With > 5K isolation RF Works make a few with choking RF Shield currents with 2 to 2.5 K choking Resistance The higher the choking resistance the better ! OCF dipoles are very bad and cause RF into Shack 73 Mike
  • K9SO
    K9SO Member ✭✭
    edited June 2019
    I've never had any luck with those "ski-handle" isolators. Some of them simply have coils of RG-58 cable crammed up inside the tube and they burn up when running a KW. 

    Mike has a good suggestion. Buy a good one. 
  • Tom W3FRG
    Tom W3FRG Member ✭✭
    edited June 2019
    You can make your own from an unused 1:1 current balun.
    Just take the twin lead end (OWL) and convert it to a connector of your choice.
    You will need to open up the OWL end of the balun housing, Remove the leads from the bolts and connect the UHF connector as close as possible to the ferrite as the coax end is connected.
    The current baluns that typically work best are the units that have ferrite vs coax.

    Tom W3FRG
  • Steven WA8Y
    Steven WA8Y Member ✭✭
    edited June 2019
    Like you, I have found loose connections ( i.e., bad soldering, no soldering, tarnished or corroded connections) to be the largest share to RF (and SWR) troubles.
  • Michael Wheatley
    Michael Wheatley Member ✭✭
    edited June 2019
    I vote for Palomar Engineering if you have RFI problems.  I sent them an email describing my rig, amp and antenna setup and they gave me great advice on how to fix it.

    Michael - KM6LHD

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