There are two potential problems with this. As general rules:
1.) Grounding any antenna which is dependent on a ground system to be
resonant will maximize reradiation.
2.) Resonant elevated radials, even without an antenna connected, are
resonant and re-radiate.
3.) Things that are not resonant can still re-radiate.
To minimize coupling from a resonant radial, the radial has to be
disconnected from ground and from other radials.
Different systems can be different, and in some cases re-radiation can
actually cause a null that reduces noise, but the general rule is
self-resonant antennas with a ground (Marconi), or nearly self-resonant
antennas when grounded, should be floated. Other antennas can be terminated
in an inductor, capacitor, or opened, depending on the system.
My 220 ft insulated tower, in the center of a four square, is "opened" by
shorting a specific length of coax to the "L" matching network. It has much
more radiation when open or grounded. radiation is minimal when detuned by a
proper impedance.
73 Tom
----- Original Message -----
From: <mikefurrey@att.net>
To: "Jim Koshmider" <k8oz1@yahoo.com>; <topband@contesting.com>
Sent: Wednesday, June 20, 2012 1:06 PM
Subject: Re: Topband: TX ANT TO RX ANT COUPLING
> Hi Jim,
>
> I just use a simple SPST open frame relay to ground the vertical section
> of the antenna and no I do not use QSK ... yet ... (need to add it to the
> old amp) The vertical section is about 60’ and the rest is horizontal at
> about 80’ up. Yes, I have been very pleased with this for this lot. I have
> thought about the flag antennas (Waller) and the Hi-Z antennas for rx and
> will experiment with that in the future. Oh yes, I have a relay that
> grounds the feed on the K9AY loop during transmit as to not get too much
> signal into the front end of the rig (K3).
>
> Just let the DX know you are in NM and they will come calling :) I grew
> up in Hobbs, NM and it worked.
>
> 73, Mike
>
> From: Jim Koshmider
> Sent: Monday, June 18, 2012 12:09 PM
> To: mikefurrey@att.net
> Subject: Re: Topband: TX ANT TO RX ANT COUPLING
>
> Outstanding job, Mike...!
>
> It's encouraging to hear about your successes. Your results are
> amazing.
>
> I have a similar situation here, in Albuquerque, and am in the
> process of setting up my Inverted L - essentially the same way as yours.
> I tried a different configuration, using a shorter vertical component of
> the "L" (only about 33 feet tall), but I am convinced that having a taller
> vertical component (about 44 feet tall) will give me a better low-angle
> signal. Since I don't have the benefit of having tall pines in my yard,
> the horizontal part of my "L" will droop down to about 25 feet at the end.
> Still that's not too much of a handicap.
>
> About your relay for grounding your transmit antenna... do you use a
> vacuum relay? { If you don't use QSK, I suppose a typical latching relay
> would work just as well. }
>
> I'm sure glad you commented on this issue. I was beginning to wonder
> if I would ever be able to work outside the continental US on 160! (Ha!)
>
> 73, and best DX,
>
> Jim, K8OZ
>
>
> --- On Mon, 6/18/12, mikefurrey@att.net <mikefurrey@att.net> wrote:
>
>
> From: mikefurrey@att.net <mikefurrey@att.net>
> Subject: Re: Topband: TX ANT TO RX ANT COUPLING
> To: topband@contesting.com
> Date: Monday, June 18, 2012, 8:34 AM
>
>
> I perhaps have maybe a worst case scenario ... I live on a 60' by
> 90' lot in
> Houston. Fortunately I have some very nice tall pine trees that
> support my
> inverted L. It has one elevated radial in the shape of an L about
> 20' above
> the ground and the antenna is fed through a current balun. One leg
> of my
> K9AY loop is within 6' of the elevated radial and 40' from the
> antenna. Yes,
> I get significant noise transferred from the transmit antenna to
> the K9AY
> loop on receive. As per ON4UN's book, he suggests to ground the TX
> antenna
> during receive and I set up a relay to do such and as a result,
> there is a
> significant decrease in the received noise from the loop. The power
> line in
> my area is underground, underneath and parallel for some distance
> with that
> radial.
>
> Just what I have managed to do here and have worked 155 countries
> with 600
> W.
>
> 73, Mike WA5POK
>
> -----Original Message-----
> From: W2PM
> Sent: Monday, June 18, 2012 5:50 AM
> To: Bill and Liz
> Cc: <wlmailhtml:/mc/compose?to=topband@contesting.com>
> Subject: Re: Topband: TX ANT TO RX ANT COUPLING
>
> Do you have much noise in the first place to reradiate? Line noise
> also is
> very spotty along a power line - along the same line of wires any
> nasty
> arcing noise can be very strong or very weak at certain spots so
> the noise
> level - if you have noise - may not be strong enough to reradiate
> with any
> affect.
>
> Sent from my iPad
>
> On Jun 17, 2012, at 17:34, "Bill and Liz"
> <wlmailhtml:/mc/compose?to=magoo@isp.ca> wrote:
>
> > I have been following the thread with interest. I have a K9AY
> and a DO
> > loop
> > located within 60 to 75 ft of the TX vertical at our summer home.
> > Interestingly, I find both these antennas very quiet with no sign
> of noise
> > being coupled to them via the TX antenna. I work a lot of DX
> from this
> > location on topband using these loops as well as a pair of
> Beverages, both
> > of which also pass fairly close to my TX vertical and both of
> which are
> > very
> > quiet.
> >
> > So, why am I not hearing this noise many are experiencing? The
> TX
> > vertical
> > is a 60 ft toploaded affair and I do not de-tune it on receive.
> All I
> > have
> > done is to run all the feedlines for both RX antennas and the TX
> vertical
> > underground in different conduits to a remote switching location.
> Someone
> > please tell me why I am missing out on all the fun of having
> noise on my
> > RX
> > antennas.
> >
> > Bill, VE3CSK
> >
> >
> >
> > -----
> > No virus found in this message.
> > Checked by AVG - www.avg.com
> > Version: 2012.0.2180 / Virus Database: 2433/5075 - Release Date:
> 06/17/12
> >
> > _______________________________________________
> > UR RST IS ... ... ..9 QSB QSB - hw? BK
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
>
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
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