[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [IRCA] [NRC-AM] DKAZ Antenna

My limited experience at Grayland says that it was somewhat like the variable termination on the Flag, Chuck, which we discussed once before. That is, a better null could be obtained at, say +/- 45 degrees from the null at 180 degrees (i.e.off the back) by adjusting the termination, but at the expense of the null directly off the back. With the DKaz the variation in termination value is not so wide however, nor can decent nulls be obtained a long way from 180 degrees as they can with the Flag.
In EZNEC, I believe that if you look at the vertical polarization plot, it shows some nulls not collinear with the antenna when the termination is adjusted slightly, but in real life, to best null mid band Seattle and Portland stations at Grayland, the optimum termination needed to be lowered by up to a couple of hundred ohms if my notes are correct.
I wonder if Mark Durenberger has some information to add? I don't think the spread that he had in termination values was so large as what I observed. 

More research is needed.  More vacation time too.

best wishes,

Nick





At 04:47 20-08-15, you wrote:

Nick -
Are you saying the DKAZ null can actually be steered? If so, how much?Or are you saying that deepening the null at 180 degrees means that the null at other angles near 180 benefit from the deeper 180 null? (Assumedly the latter. I've not been able to steer a DKAZ null, only improve it a bit.) 
Chuck

> Date: Thu, 20 Aug 2015 04:37:15 +0000
> To: irca@xxxxxxxxxxxxxxxx
> From: nhp@xxxxxxxx
> Subject: Re: [IRCA] [NRC-AM]  DKAZ Antenna
>
> If you get ambitious Jim, try a Vactrol termination, like Mark C.
> used in  his Flag antenna.   It's amazing how stations fairly far off
> the exact back end of the antenna get better nulls with a remotely
> variable termination.  At Grayland, it even helped kill the local noise..
>
> best wishes,
>
> Nick
>
>
> At 15:29 19-08-15, you wrote:
> >Hi Neil,
> >
> >Thanks from a happy DKAZ user. The antenna took 3 weekends to build,
> >due to the Texas heat, clearing a path through the trees and
> >gathering all the supplies. I decided to make this a permanent
> >installation, using 4"x4" timber posts for the main supports and 2"
> >electrical PVC pipe for the 22' supports, all seemed to work just fine..
> >As for the termination, I will try a 5k pot and see if I can get a
> >better null to the north. The Dallas station come in pretty good
> >here, 570 KLIF, 820 WBAP, these would be the stations I would like
> >to null. Also, at present I am using coax direct onto the feed end
> >of the antenna, so I have not added the matching transformer as yet, next step. 
> >
> >As for San Angelo stations, I have only logged KGKL 960 but nothing
> >else at present.
> >I really don't have enough width on my land for a side by side DKAZ,
> >sounds like a great idea though.
> >I am presently working on my Spanish, I know some which helps with
> >station identifications, but more is helpful.
> >
> >Thanks
> >James
> >
> >
> >
> >---- neilkaz <neilkaz@xxxxxxxxxxxxx> wrote:
> > > 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
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >---
> > > >This email has been checked for viruses by Avast antivirus software.
> > > >https://www.avast.com/antivirus
> > > >_______________________________________________
> > > >IRCA mailing list
> > > >IRCA@xxxxxxxxxxxxxxxx
> > > >http://montreal.kotalampi.com/mailman/listinfo/irca
> > > >
> > > >Opinions expressed in messages on this mailing list are those of
> > the original contributors and do not necessarily reflect the
> > opinion of the IRCA, its editors, publishing staff, or officers
> > > >
> > > >For more information: http://www.ircaonline.org
> > > >
> > > >To Post a message: irca@xxxxxxxxxxxxxxxx
> > > >
> > >
> > > _______________________________________________
> > > Now accepting Pre-orders for the
> > > 36th Edition of the AM Radio Log
> > > http://www.nrcdxas.org
> >
> >_______________________________________________
> >IRCA mailing list
> >IRCA@xxxxxxxxxxxxxxxx
> >http://montreal.kotalampi.com/mailman/listinfo/irca
> >
> >Opinions expressed in messages on this mailing list are those of the
> >original contributors and do not necessarily reflect the opinion of
> >the IRCA, its editors, publishing staff, or officers
> >
> >For more information: http://www.ircaonline.org
> >
> >To Post a message: irca@xxxxxxxxxxxxxxxx
>
>
> _______________________________________________
> IRCA mailing list
> IRCA@xxxxxxxxxxxxxxxx
> http://montreal.kotalampi.com/mailman/listinfo/irca
>
> Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers 
>
> For more information: http://www.ircaonline.org
>
> To Post a message: irca@xxxxxxxxxxxxxxxx
>

_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca
Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers 

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx



_______________________________________________
IRCA mailing list
IRCA@xxxxxxxxxxxxxxxx
http://montreal.kotalampi.com/mailman/listinfo/irca

Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers

For more information: http://www.ircaonline.org

To Post a message: irca@xxxxxxxxxxxxxxxx