[TenTec] Built in SWR meter bannans

[Rick - DJ0IP / NJ0IP]

Charles, you are digging back in history now.
In fact the story I told was closer to 30 years ago.
A lot has changed in the meantime, including my knowledge on the subject.

Back then, I bought (for that time in history) some very expensive
commercial baluns and they still burned up.
It's not a question of money, it's a question of knowledge (in that case,
lack of it).

You can't 'always' just add more ferrite.
Most of my operations in the past 30 years have been portable, using
lightweight fiberglass poles.
Even one single FT-240 is too heavy for the top of the pole.  You have to
drop the feedpoint down the pole.
If you drop the feedpoint down the pole, you lose height.  Height is might.

The solution involves more than the choke.
So the target is to get it right, without over-doing it.
So this brings me back to the question I posed earlier, just how much
ferrite do you really need for different power levels and for different
applications?

I would like to see some real life examples:
How much do we need in a beam?
How much do we need in a dipole?
How much do we need if the choke is between an openwire fed dipole and an
asymmetrical matchbox?

SPECIFICS please.  "Enough" is not very helpful.

Jim gave us some exact examples in an earlier post and that is very useful.
Steve has an excellent web site showing some specific recommendations of
chokes we can build.
See: http://www.karinya.net/g3txq/chokes/ 
THAT is what helps the ham community, not statements about spending money or
find another hobby.

Also best regards,

Rick, DJ0IP


-----Original Message-----
From: TenTec [mailto:tentec-bounces at contesting.com] On Behalf Of Charles P.
Steinmetz
Sent: Wednesday, April 24, 2013 8:18 AM
To: Discussion of Ten-Tec Equipment
Subject: Re: [TenTec] Built in SWR meter bannans

Rick wrote:

>It seems you would want to use wire whose insulation will not melt 
>before the saturation temperature of the core.

Well, that's fine, but the core should never be anywhere near its saturation
temperature.  If it is, you have lots worse problems than the temperature
rating of the wire you used.

>If I stack several cores together, then I won't have a problem with 
>heating, but that is expensive.  It would be a cheaper solution to use 
>less cores and more expensive wire.

But, as Jim and I have been saying, they do not trade off that way.  You
either have enough core, or you don't.  If you don't, it doesn't matter what
kind of wire you use, you'll still burn it down.  How many times does it
take burning down inadequate baluns to make it cheaper to do it right the
first time?

I'm sorry, but anyone who won't spend the money necessary to make a proper
antenna balun should find a new hobby.

Best regards,

Charles








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