--- Begin Message ---
- Subject: Re: [NRC-AM] [IRCA] DKAZ Antenna
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Wed, 19 Aug 2015 08:14:39 -0400
- Delivered-to: irca@xxxxxxxxxxxxxxxx
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The typical end-fed unterminated wire - call it longwire or shortwire but basically anything 50 to 300 ft. - has SLIGHT nulls / minima at a right angle to the wire and slightly more pick-up in the direction heading away from the feedline / receiver (maybe a dB or two). In general, such a wire is not very directional.
You can get good nulls by having two of these wires at a right angle and then phasing them with the Quantum Phaser or similar.
Though the simplest approach is bringing the wire(s) directly to the receiver or phaser, use of external grounding and an isolation / impedance-matching transformer on each antenna can noticeably improve the signal-to-noise ratio.
Mark Connelly, WA1ION
South Yarmouth, MA
<<
Okay guys help me out here. I always thought the sensitivity of a 'short'
wire antenna was primarily from the sides, so that the wire would need to be
orthogonal to the target signals.
James' 150 feet would seem to be a
'short' antenna on the Medium-Wave band;
I'm assuming his wire is
elevated.
So is it accurate to compare reception from the END of this
long-wire with a
directional antenna oriented ALONG the wire's azimuth? I
know the answer is
yes when the wire antenna approaches 1 wavelength...but I
wonder about 150
feet.
...ready to be enlightened...
Cheers!
Mark
Durenberger
-----Original Message-----
From: neilkaz
Sent: Tuesday, August
18, 2015 8:41 PM
To: Mailing list for the International Radio Club of America ;
'NRC'
Cc: am@xxxxxxxxxxx
Subject: Re: [IRCA] DKAZ Antenna
This is good to
hear about another happy DKAZ user. You may find that you
are an even more
happy DKAZ user if you spend the effort to manually fine
tune Rt to see if you
can get even better back nulls. This is best done in
the daytime. I'd guess
you might improve back nulls by a few dB unless 900
ohms is perfect. I do
realize that you probably don't have much daytime
stuff from 300 deg into
Austin. Does San Angelo come in?
Do you have land to array two of these side
by side for a more narrow
beamwidth?
If not fluent in Spanish aimed at 120
from Austin, I expect you'll want to
improve your command of that language.
73 KAZ
-----Original Message-----
>From: James Niven
<jniven@xxxxxxxxxxxxx>
>Sent: Aug 18, 2015 8:11 PM
>To: 'NRC'
<am@xxxxxxxxxxx>
>Cc: 'Mailing list for the International Radio Club of
America'
><irca@xxxxxxxxxxxxxxxx>
>Subject: [IRCA] DKAZ Antenna
>
>Hi
All,
>
>
>
>Just wanted to report I have completed my DKAZ antenna over the
past
>weekend
>and I have had a chance to test it out the past few
nights.
>
>I followed the design as Mark Durenberger's
article
>http://www.durenberger.com/documents/DKAZREPORT051214.pdf I built the
140
>foot long with 22 feet high supports. I am at present using a 900 ohm
fixed
>1 watt resistor and the direction is 120 degree.
>
>
>
>I have been
comparing the DKAZ to my present 150 foot longwire running
>pretty much in the
same direction, so far, the performance of the DKAZ has
>been very encouraging.
Signals are appearing a lot stronger and earlier in
>the evening than the
Longwire and I can tell signals from the north are
>reduced, while signals from
the South are a lot stronger and louder.
>
>
>
>On a couple of frequencies I
have checked, on the DKAZ there is a station
>with a decent signal while the
Longwire has no station at all or a
>different
>station.
>
>I am still to
hear a new station with this antenna but it will happen.
>
>
>
>Thanks for
the fine article Mark and answering my questions.
>
>
>
>James
Niven
>
>Austin, Texas
>>
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