A BALUN and an RF Choke are synonymous. They are the exact same thing
(except for the connection terminals).
People often use different names to distinguish at what point we are using
them, but they are all simply common mode current chokes!
If you have any doubts on this, read W7EL's paper on "Baluns: What they do
and how they do it".
Download here: http://www.eznec.com/Amateur/Articles/Baluns.pdf
And for more in-depth details, read K9YC's paper "RFI-Ham" (full name is:
"A Ham's Guide to RFI, Ferrites, Baluns, and Audio Interfacing".)
http://audiosystemsgroup.com/RFI-Ham.pdf
Not sure what you are calling a sleeve balun, John.
It sounds like you mean the "beads over coax" type balun.
This is actually a W2DU (Maxwell) balun.
A sleeve balun is when you run a physical quarter wavelength of something
over the outside of the coax.
Perhaps the Maxwell is also called a sleeve balun now days. It is similar
in that it slips over the coax.
The "wound" balun is either a Guanella (current balun) or a Ruthroff
(voltage balun). It is very important to distinguish between them. Most of
the time we should be using a Guanella (current) Balun.
The Guanella is superior to the Maxwell in its ability to impede common mode
current, but the Guanella is also more frequency dependent. The core
material and number of turns determine its frequency range.
That's why in some situations one works better than the other.
If the Guanella is not designed properly for the frequency in question, it
will not do a good job. In that case the Maxwell is better. But if the
Guanella is designed properly, it is significantly better than the Maxwell.
Now the problem: It is basically impossible to design a Guanella that works
well over the entire hf spectrum.
Again, everything you ever wanted to know (and more) is explained by Jim in
his RFI-Ham.
Now the hammer; Mike, you should get the proper external capacitor (1000 pF)
and try again, but tune VERY slowly and VERY carefully. Like I said
earlier, I also thought my 238 would not match my 160m antenna, as I was
hurriedly hunting for a match before a contest. After the contest and with
a lot more patience, I found a perfect match, but the tuning was so sharp,
all you had to do was breath on it and you would throw it off.
IT IS VERY EASY TO BLOW RIGHT PAST THE PROPER SETTINGS WITHOUT EVEN
NOTICING.
73
Rick, DJ0IP
-----Original Message-----
From: TenTec [mailto:tentec-bounces@contesting.com] On Behalf Of John
Huffman
Sent: Thursday, October 31, 2013 6:32 PM
To: tentec@contesting.com
Subject: Re: [TenTec] 160 meters, ten ted 238 tuner, part two
I agree with Bob. But, having no technical background I tend to do things
the 'ham' way. I'd try a different 1:1 balun. I know they should be the
same, but experience the problems you describe with a wound balun at times.
The problems are not there with a sleeve balun.
And, sometimes the sleeve had problems but the wound one doesn't. A choke
balun is another thing to try.
I keep trying things until I happen upon a setup that works well on all
bands with a particular antenna and tuner. I've only had limited success
with changing wire or feeder length. More luck changing balun and the coax
length between the balun and tuner.
The 238 and the Palstar should both work well. The 238 will need the
external cap on 160m. I believe your issue is not the tuner.
73 de K1ESE
John
On 10/31/2013 1:17 PM, Bob McGraw - K4TAX wrote:
> Having gone back and reviewed some 30 or so e-mail exchanges on this
> topic, it is my conclusion that the length of the wire should be OK
> and the type and length of the feed-line should be OK. Further,
> this configuration should be relatively easy for most all external
> tuners to affect a good match, all bands, from 160M - 10M. There is
> something yet to be discovered in, with, or related to the
> installation that is the cause of this issue.
>
> The fact that the 253 Automatic tuner finds a match, somewhat affirms
> that the wire length. antenna position and the feed-line type/length
> is not the issue.
>
> 73
> Bob, K4TAX
>
>
>
> ----- Original Message ----- From: "Mike Bryce" <prosolar@sssnet.com>
> To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
> Sent: Wednesday, October 30, 2013 2:11 PM
> Subject: [TenTec] 160 meters, ten ted 238 tuner, part two
>
>
> Well gang,
>
> It's great being able to move again and once more I'm in the shack.
>
> I did some interesting testing with my doublet.
>
> here's a recap
>
> 132 feet on each side fed with 180 ish feet of 600 ohm open line. That
> goes to an external 1:1 balun feed with three feet of LMR400 to the
> coupler.
>
> A palstar coupler and the Ten Tec 238 coupler were unable to find a
> match.
>
> So I added 15 feet to both ends.
>
> No joy.
>
> I added about 10 feet of wire inside the shack and strung it across
> the ceiling. Looks like hell, but it's up there
>
> The palstar will find a solution at 1.890 now, but the swr is around
> 2.7:1
>
> The 238, not so much. I did get it to tune, but the SWR slowly
> increased (I plan on modifying the coupler with the high voltage
> doorknob caps)
>
> Now, here's the odd part.
>
> I have a Ten Tec 253 AUTOMATIC tuner. That tuner found a solution for
> the 160 meter band from one end to the other.
>
> Happy days!
>
> But, using the same tuner, it can't find a solution on 30 meters.
>
> But the 238 and the palstar will tune it flat.
>
> I don't mind changing antennas, but swapping out couplers to operate
> from one band to the other kinda sucks.
>
>
> Mike WB8VGE
>
>
>
> Knowledge is knowing a tomato is a fruit; Wisdom is not putting it in
> a fruit salad.
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>
>
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