[TowerTalk] PARASLEEVE ANTENNA ELEMENTS
Mike Lamb
n7ml@imt.net
Mon, 25 Jan 1999 16:56:56 +0000
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Hello Pete:
We discussed this thread a few months back when I pointed out that I found that
I had a big SWR change from one week when I tuned my C3d one and the next week,
the resonant frequency on 10 meters shifted by a couple hundred kHz. The only
difference was that one week there was no wind and the other week there was
wind.
To fully appreciate the difference, you need to look at the SWR curve because if
you look at the SWR at one end of the dip, it is possible to have a shift of a
couple hundred kHz in resonant frequency and see little variance in SWR at a
single frequency.
Just wanted to throw in another parameter!
73/Mike, N7ML
Pete Smith wrote:
> At 10:42 AM 1/25/99 -0500, David Clemons wrote:
> >
> >Hi,
> >
> > Although it may be noted that a disadvantage of this type of antenna
> >is SWR fluctuations during windy days, I also experience this with my 204CD
> >(a 4 element Cushcraft 20 meter yagi which does not use this method).
> >
> > This is not meant as a criticism of Cushcraft's antenna, but rather
> >just as a note to not decide to use the Force 12 antenna simply for this
> >reason (since it will probably happen to some of the alternative antennas).
>
> Moreover, the largest SWR excursion I have noticed with the C-3 is on the
> order of .2 -- from 1.3-1.5:1 -- despite some very lively winds and a lot
> of element movement. This seems most pronounced on 15 meters.
>
> 73, Pete N4ZR
> Loud is good
>
> --
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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Hello Pete:
<P>We discussed this thread a few months back when I pointed out that I
found that I had a big SWR change from one week when I tuned my C3d one
and the next week, the resonant frequency on 10 meters shifted by a couple
hundred kHz. The only difference was that one week there was no wind
and the other week there was wind.
<P>To fully appreciate the difference, you need to look at the SWR <FONT COLOR="#FF0000">curve
</FONT><FONT COLOR="#000000">because if you look at the SWR at one end
of the dip, it is possible to have a shift of a couple hundred kHz in resonant
frequency and see little variance in SWR at a single frequency.</FONT><FONT COLOR="#000000"></FONT>
<P><FONT COLOR="#000000">Just wanted to throw in another parameter!</FONT><FONT COLOR="#000000"></FONT>
<P><FONT COLOR="#000000">73/Mike, N7ML</FONT>
<P>Pete Smith wrote:
<BLOCKQUOTE TYPE=CITE>At 10:42 AM 1/25/99 -0500, David Clemons wrote:
<BR>>
<BR>>Hi,
<BR>>
<BR>> Although it may be noted that
a disadvantage of this type of antenna
<BR>>is SWR fluctuations during windy days, I also experience this with
my 204CD
<BR>>(a 4 element Cushcraft 20 meter yagi which does not use this method).
<BR>>
<BR>> This is not meant as a criticism
of Cushcraft's antenna, but rather
<BR>>just as a note to not decide to use the Force 12 antenna simply for
this
<BR>>reason (since it will probably happen to some of the alternative antennas).
<P>Moreover, the largest SWR excursion I have noticed with the C-3 is on
the
<BR>order of .2 -- from 1.3-1.5:1 -- despite some very lively winds and
a lot
<BR>of element movement. This seems most pronounced on 15 meters.
<P>73, Pete N4ZR
<BR>Loud is good
<P>--
<BR>FAQ on WWW:
<A HREF="http://www.contesting.com/towertalkfaq.html">http://www.contesting.com/towertalkfaq.html</A>
<BR>Submissions:
towertalk@contesting.com
<BR>Administrative requests: towertalk-REQUEST@contesting.com
<BR>Problems:
owner-towertalk@contesting.com
<BR>Search:
<A HREF="http://www.contesting.com/km9p/search.htm">http://www.contesting.com/km9p/search.htm</A></BLOCKQUOTE>
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FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Search: http://www.contesting.com/km9p/search.htm