Knots in antenna wire?
 

I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Ken KC2JDY


Ken
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"Ken" wrote in message
...
I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Ken KC2JDY

I would say yes - it would have an effect - but not so much on propogation
as efficiency - I think the knot would act as a loading coil.
I would think it best to strip the insulation so the whole knot is bare
copper.



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On Sat, 09 Oct 2004 03:30:33 GMT, Ken wrote:

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Hi Ken,

YES, at wavelengths of 1cM that 1cM knot puts the twists to RF.

NO, at wavelengths of 160M that 1cM knot is invisible.

MAYBE, between those two extremes your answer varies in proportion.

73's
Richard Clark, KB7QHC

"Ken" wrote in message
...
I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Ken KC2JDY



Your voice comes out with a knot in it.... ;-)



Ken
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"Ken" wrote in message
...
I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

it has absolutely NO effect on propagation. it might have a tiny effect on
the feedpoint impedance at uhf, but then again you most likely won't use an
antenna like that at those frequencies. i have always thought that buying
wire antennas was the worst possible thing to do, they are expensive
relative to the material that goes into them, they are no better than
something you can build from stuff found around the house, and they are full
of excuses... they are too long for your property: if you built from
scratch you would cut it off and use it anyway, if you buy it you don't want
to cut it. it doesn't present a good swr: if you build it you trim and
adjust until it works or just put a tuner on it and forget it, if you bought
it then the problem must be the balun or a trap so send in to get a
replacement instead of getting on the air. etc, etc, etc.

On Sat, 9 Oct 2004 11:24:57 -0000, "Dave" wrote:

I have always thought that buying
wire antennas was the worst possible thing to do . . .

I am in general agreement. I asked because I am making my own QRP 40M
double zepp and was trying to decide how to attach the 26 ga stranded,
insulated copper clad steel wire to the center conductor. I like to
leave the insulation on because the knot does not weaken the wire as
much as putting a knot in bare wire (smaller radii). I was
considering stripping a section of the wire just beyond the knot and
soldering the feed lines there, but figured it just wasn't worth the
trouble.

Ken KC2JDY



Ken
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I have heard of people putting a knot in an
appliance cord to stop lightning surges getting to
equipment! :-)

Murray vk4aok

Ken wrote:
I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Ken KC2JDY


Ken
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remove "zz" from address)

This also keeps the elephants away. I haven't had any elephant problems
since I started doing this.

--
Steve N, K,9;d, c. i My email has no u's.

"Murray" wrote in message
...
I have heard of people putting a knot in an
appliance cord to stop lightning surges getting to
equipment! :-)

Murray vk4aok

Ken wrote:
I have seen commercial wire antennas where the insulated wire is tied
to the center insulator with a clinch knot having three turns and then
the end of the wire (protruding from the knot) is stripped and
connected to the feedline.

Does forcing the RF current though a knot at the feedpoint have a
significant affect on propagation?

Ken KC2JDY


Ken
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remove "zz" from address)

It's crocodiles here!
Murray

Tom Ring wrote:
Steve Nosko wrote:

This also keeps the elephants away. I haven't had any elephant problems
since I started doing this.


I use it to keep the wolverines away, and it is 100% successful so far.

tom
K0TAR

Tom Ring wrote:

Steve Nosko wrote:

This also keeps the elephants away. I haven't had any elephant problems
since I started doing this.


I use it to keep the wolverines away, and it is 100% successful so far.


It also stops you buying EH antennas, if the knot is good and tight.

Andy