[1000mp] coax line isolators or chokes

[kce]

I had one of the radioworks models that went to hell in a very short time.
inside its nothing more than what looked like a short piece of  very thin
coaxial cable inserted into about 18 very small FB's, with the whole thing
in a expansion type foam.. I had better luck ordering a bunch of the large
snap around rf chokes from the surplus place in Neb. Snap 6 or so of them
dudes around a piece of rg213 and your in business.
ken w8ob
----- Original Message -----
From: "Pete Smith" <n4zr@contesting.com>
To: <1000mp@mailman.qth.net>
Sent: Friday, March 07, 2003 5:43 PM
Subject: Re: [1000mp] coax line isolators or chokes


> At 05:26 PM 3/7/03 -0500, you wrote:
> >Has anyone ever opened one of the Radio Works coax line isolators?
> >http://www.radioworks.com/clitop.html
> >What is inside? Is it like the choke in ARRL Handbooks with steel wool
> >inside a tube?
> >
> >I have what seems like a similar product CF5KV "High-Q Common Mode Choke"
> >from rf inquiry of Japan. http://www.rfinq.com/
> >
> >It seems to have helped rfi problems here, MarkV and 91-beta amp. They
> >claim to have sold 20,000 to the Japanese market but don't mention sales
> >numbers in USA. They give some interesting measurements on the web site
> >which I had not seen before. Since it was kind of expensive I haven't
> >opened it either. I hope it is full of ferrite washers and not steel
wool!
> >
> >ron w8gus.
>
> These things are grotesquely expensive, particularly the oddly-named
> Japanese unit.  Anyone can make up a common mode choke that is just as
> effective with 50-100 ferrite beads from Fair-Rite or Palomar and a length
> of teflon-jacketed coax.  The only trick is choosing the right ferrite
mix,
> and then putting the choke in the right place on the line.  I have never
> mastered the latter trick, so I tend to overdo it and put them at a couple
> of different places.  For example, I have choke baluns at the feedpoints
of
> all my balanced antennas, a feedline choke at the entrance to the shack,
> and another between my transceiver and amplifier.  Seems to work, but then
> I haven't seen any tigers in the neighborhood either, and I don't know if
> that's because of anything I've done....
>
> 73, Pete N4ZR
> The World HF Contest Station Database was updated 23 Feb 03.
> Are you current? www.pvrc.org/wcsd/wcsdsearch.htm
>
>
>
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