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

["Tom Boucher" <tom@telemetry.demon.co.uk>]

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" <alan.melia@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
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: <k2ors@comcast.net>
> To: rsgb lf reflector <rsgb_lf_group@blacksheep.org>; rsgb lf reflector
> <rsgb_lf_group@blacksheep.org>
> 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