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LF: Re: Re: LF Vertical Antennas problem...

To: <[email protected]>
Subject: LF: Re: Re: LF Vertical Antennas problem...
From: "Tom Boucher" <[email protected]>
Date: Thu, 21 Jun 2007 08:50:46 +0100
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References: <062020072228[email protected]comcast.net> <[email protected]>
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Warren

I also had a strange effect when strapping a coax fed 80m dipole at ground level for use as a 160m 'TEE'. It appeared to show 2 resonant frequencies a few Khz apart. When I strapped the feeder at the top as well as the bottom of the feeder, all was OK!
73
Tom G3OLB

----- Original Message ----- From: "Alan Melia" <[email protected]>
To: <[email protected]>
Sent: Thursday, June 21, 2007 12:29 AM
Subject: LF: Re: LF Vertical Antennas problem...


Hi Warren that sounds familiar !! I think you are using covered wire, my
guess is a break on one leg so that you do not have enough capacitance to
resonate with the original coils. A top-band dipole will still work quite
well with one leg disconnected. Can you leave out the loading coil and
measure the resonance frequency of the wire T alone that might give some
clues. I have had this effect when part of the top load comes disconnected.
Good Luck with it
Cheers de Alan G3NYK

----- Original Message -----
From: <[email protected]>
To: rsgb lf reflector <[email protected]>; rsgb lf reflector
<[email protected]>
Sent: 20 June 2007 23:28
Subject: LF: LF Vertical Antennas problem...


Hello the list,

I have in the past used my 160 meter dipole as a vertical "T" by tying
the feeders together and using a tapped loading coil to resonate and match
the antenna. I could get a perfect 50 ohm match in this manner and it
radiated quite well - Hartmut copied my transmission running around 100
watts. I have also used the same setup on 500kHz with a different loading
coil successfully.
   Now I find that I cannot resonate the antenna - I can't eliminate the
reactance no matter what the setting of the tap or the coil. The best I can
do is an swr of 1.7:1 and at least 40 ohms of reactance. I have tried
changing coils and still the problem persists.  If I do transmit this way,
my signal seems to be down at least 10dB below what it was when the antenna
resonated properly. Any thoughts?

--
73 Warren K2ORS/WD2XGJ/WD2XSH/23/WE2XEB/2
FN42hi
http://www.w4dex.com/wd2xgj.htm




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