[Elecraft] Now General RF Issue WAS 160m loop experiment a big failure

[Fred Jensen]

On 10/20/2011 8:24 PM, Ron D'Eau Claire wrote:
> I wholeheartedly endorse Don's comments.

I do too.
>
> A good practice with any antenna installation is to check the SWR on each
> band for which it is used, and make a note of that.

While in Comm Officers' School at Keesler AFB many years ago, I was 
active in the radio club [K5TYP].  We had a tribander up about 40 feet 
or so that never worked.  We borrowed some test equipment and measured 
the impedance on 20, 15, and 10, and it was almost exactly 50 ohms [and 
the same on all bands which should have been a clue].  After several 
weekends of work including several trips up the tower, one of the guys 
said, "Let's do this one more time," and cranked the frequency of the 
impedance bridge down to 20m again.  Nothing changed.  The bridge saw 50 
ohms at 14 MHz, 15 MHz, 18 MHz [which wasn't a ham band then], ... 
everywhere else, including 80m.  We finally figured out we had the 
longest 50 ohm dummy load in Harrison County.

I'm not real clear on how faulty coax could cause his RFI symptoms, 
unless maybe none of the power is actually getting to the antenna and is 
"backing up" [a technical plumbing term] into the shack.  That it 
started with the propane tank episode is certainly suspicious.  OT's may 
remember the old adage, "Note carefully from which corner of the chassis 
the smoke comes, that's where you want to begin troubleshooting."

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org