[TenTec] Tuner

[Rick - DJ0IP / NJ0IP]

Jim, all things are relative.

We don't all have room for a tower and beam like you do.
In fact here in Europe, very few people do.  Less than 1% of us.

The OCF is about the only way to get a single wire to work on many bands,
unless you feed with openwire.
Openwire is a good option but not always an possible.
The reality is, a lot more people are forced to use this "bad antenna" then
you might think.

However if they must, there is this great source of information on combating
the RFI and CMC problems.
It's called "RFI HAM".  Ever seen it?  (hi)

And there is another great source here in Europe, GM3SEK, who shows some
practical examples of how to use commonly available components here in
Europe to build chokes, based on K9YC's work.  With these and our lower
power levels anyway, we can tame the beast.

Yes, it's a crutch, but at least it gets people walking again.

73
Rick, DJ0IP

-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Jim Brown
Sent: Tuesday, July 09, 2013 8:22 AM
To: tentec at contesting.com
Subject: Re: [TenTec] Tuner

On 7/8/2013 12:42 PM, Richards wrote:
> (I use Off Center Fed (OCF) antennas because they tend to work on 
> their EVEN harmonics...)

OCF antennas have inherently high imbalance, which makes their feedline part
of the antenna, which makes them pick up lots of noise (and also puts RF in
the shack).  They are not easy to choke, because the high level of imbalance
places a very high common mode voltage across the choke, which will often
fry the choke, even at moderate power levels.

MANY years ago, when the world was much quieter, and when homes were not
full of entertainment equipment with Pin One Problems, OCF antennas were a
very good idea.  That was then, and now is now. And NOW they are a BAD idea.

73, Jim K9YC
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