[Hi-zreceivingarraydiscussions] Detuning antennas when using 4 sq

[kd9sv]

Doug, go to max gain systems (or google vacuum relays) Allan Bond sells the
used RJ-1A or another similar unit with a 12v coil which is easier to
interface.  They are very reasonable and with 8ms op/rel times can be used
even with a qsk system.  BTW, Alpha uses RJ-1's in their amplifiers.
Probably on the ground radials would be less of a problem than raised
radials for re-radiation...also this could still be a problem with RX on 80
meters as your antenna would be 1/2 wave on 80...de gary

-----Original Message-----
From: hi-zreceivingarraydiscussions-bounces at hizantennas.com
[mailto:hi-zreceivingarraydiscussions-bounces at hizantennas.com] On Behalf Of
Doug Turnbull
Sent: Thursday, September 20, 2012 3:43 PM
To: hi-zreceivingarraydiscussions at hizantennas.com
Subject: [Hi-zreceivingarraydiscussions] Detuning antennas when using 4 sq

Gentlemen, 
     I am using a good balun on the feed line of the TB Inverted L to
decouple it.   Gary, who manufactures the vacuum relay and where are they
available?   I understand that you are suggesting to break the sky hook
close to the point where it connects to the transmit antenna the radial
system being left in place.    I am presently using raised radials and so
these may complicate the issue.    I wonder if ground mounted radials would
be as problematic as I am likely to make the change to an extensive ground
radial system.   Thank you for advice already given and any more information
you may have.

            73 Doug EI2CN




----------------------------------------------------------------------
, 

       I am using a Hi-Z four square and find that then my 160M inverted L
is down that it works better on both TB and 80M.   Obviously there is an
interaction and yes it is certainly closer than two hundred feet to the
closest point of the 4 sq.    What method of detuning antennas such as the
inverted L is normally used?    I suppose a relay switching in or out is
part of the system and the problem then becomes that when operating on TB
the TX antenna must be detuned possibly slowing down operations and if not
properly thought out problematic for a power amplifier.

 


                                     73 Doug EI2CN



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Content-Type: text/plain;	charset="us-ascii"

Doug, I would use an RJ-1A vacuum relay to open (disconnect) the antenna
from the feedline...if no current can flow in the antenna wire it should not
re-radiate and bother the 4 square...de gary

-----Original Message-----
From: hi-zreceivingarraydiscussions-bounces at hizantennas.com
[mailto:hi-zreceivingarraydiscussions-bounces at hizantennas.com] On Behalf Of
Doug Turnbull
Sent: Wednesday, September 19, 2012 3:15 PM
To: hi-zreceivingarraydiscussions at hizantennas.com
Subject: [Hi-zreceivingarraydiscussions] Detuning antennas when using
4square





------------------------------

Message: 3
Date: Wed, 19 Sep 2012 15:58:44 -0400
From: Roger D Johnson <n1rj at roadrunner.com>
To: Hi-Z Receiving Array Discussions
	<hi-zreceivingarraydiscussions at hizantennas.com>
Subject: Re: [Hi-zreceivingarraydiscussions] Detuning antennas when
	using 4square
Message-ID: <505A23F4.6080105 at roadrunner.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

It's a bit more complicated then that. If you open the feedline center
conductor
at the antenna (Ithink that's what you mean), you still have two half waves
on 80m.
Also, you have the combined length of half the inv V and the outer conductor
of the
feedline that's resonant somewhere! Doug..do you have a good balun to
prevent
this?

73, Roger







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