[Lowfer] a thought on coils

Thu, 14 Feb 2002 19:55:15 -0800

Hi again Ed. It's funny, question takes on a new meaning second time I read
it HI. If you're asking what type of core material that Walt was using, the
answer is...I don't know. I think Bill Ashlock had the right idea in that it
was of low permeability.

73
John/AB4MS/JDH

----- Original Message -----
From: Ed Tanton <[email protected]>
To: <[email protected]>
Sent: Thursday, February 14, 2002 1:57 PM
Subject: RE: [Lowfer] a thought on coils

> The questions I have are: 1) no knowledge of what ferrite; 2) where can
> I get some/a lot of, litz wire; and, finally: 3) what was the freq?
>
> 73  Ed Tanton  N4XY  <[email protected]>
>
> Ed Tanton  N4XY
> 189 Pioneer Trail
> Marietta, GA  30068-3466
>
> website:   http://www.n4xy.com
>
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>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]
> On Behalf Of john hoopes
> Sent: Thursday, February 14, 2002 2:15 PM
> To: [email protected]
> Subject: RE: [Lowfer] a thought on coils
>
>
> Bill, although I have never personally experimented with ferrite loaded
> coils, I have read various articles with the data claims you mention. It
> seems pretty discouraging at first, and had it not been for my visit to
> Walt's, I would have never given ferrite loaded coils a second thought.
>
> Walt went into some detail about his coil but the only thing I can
> remember is that the PI windings were jumble wound. That struck me as
> rather odd, but who am I to argue with success. I know Walt was a
> stickler for efficiency. He told me "If it isn't efficient, I'll rip it
> out."
>
> From what I can remember, the coil was enclosed in what appeared to be a
> 4" piece of PVC with end caps. Total length seemed to be 4" or so but it
> was hard to tell because the coil was mounted at the top of his antenna
> just underneath the top hat. I must admit I was a little disappointed at
> first because I expected to see a huge coil at the base of his tower.
> Instead there was a small aluminum box that housed a matching network
> from the transmitter to the low Z of the antenna.
>
> BTW, Walt used a home brew transceiver for both transmitting and
> receiving that was a beautiful piece of work. It is too bad that Walt is
> no longer in the hobby because his contributions are truly missed.
>
> 73
> John/AB4MS/JDH
>
>  -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]
> On Behalf Of Ashlock,William
> Sent: Thursday, February 14, 2002 12:15 PM
> To: '[email protected]'
> Subject: RE: [Lowfer] a thought on coils
>
> Hi John,
>
> >The simplest coil I ever encountered was made by Walt
> >Glazar, W3WI. His beacon WI was heard all over the East coast as well
> >as
> the
> >mid west and it consisted of nothing more than a PVC form with two pi
> >wound litz sections over a small ferrite rod. Walt was a stickler for
> >efficiency and if it didn't perform, it didn't stay in his beacon.
> >Ferrite is very useable if you don't saturate it with too much power
> >provides an easy way
> to
> >tune a coil to resonance.
>
> I have spent many hours trying to design loading coils using various
> types of ferrite cores because they appear to offer reduced size and
> ease in construction. The best Q I have been able to obtain is approx
> 100 at 150ma of current. Turns out it is very easy to saturate ferrite
> cores. I have seen boasts of transmitting performance for these coils
> from many sources, but when it comes to the actual coil Q, at the
> typical 150ma antenna current, there's always a conspicuous lack of
> data.
>
> Speaking of simple coils, using Litz on a 4" PVC pipe (preferably with
> slots) a Q of >300 is no problem at all. Not sure why the 'bucket
> brigade' approach is so popular, except for the lower cost of the house
> wire. The Rac for #14 copper wire at 185k is not really that good
> because of the 'skin effect' losses.
>
> BTW: Do have or can you get some more details about WI's loading coil?
>
> Bill
>
>
>
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