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- Subject: Re: [IRCA] KAZ versus Pennant/Flag
- From: Mark Connelly <markwa1ion@xxxxxxx>
- Date: Thu, 25 Oct 2018 02:47:17 +0000 (UTC)
- Delivered-to: irca@xxxxxxxxxxxxxxxx
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I think one question that may have been hinted-at is if you have to keep your DKAZ on the shorter side horizontally, can you make up the poor low band gain by going higher on the vertical dimension?
For the EZNEC experts: If you had two 50 ft. trees 50 ft. apart and hung up your antenna so the apex points were 46 ft. up and the base wires 6 ft. up, and had an end to end length of 100 ft., could such a DKAZ compete with one about 1.5 times that length but half the height?
Obviously gain isn't the whole game. The null zone has to be substantially wider than that of a regular Flag / SuperLoop and it has to hold up well across the band without a constant need to tweak the termination via Vactrol or something else while moving around the band.
That Powerpoint presentation referenced by Nick was interesting in that it covered many kinds of MW antennas but didn't say much about the Beverage, once considered the king of DX antennas.
I tried a reduced size (less than 80 ft. end to end) DKAZ here and, yes, it was gain-dead on the lower half of the band. I wasn't even convinced that the null zone was any better or more consistent across bandwidth than SuperLoops that have served me well here.
I have also used a Bowtie with mixed results. See http://www.qsl.net/wa1ion/pictures1/bowtie_s_yarmouth.gif for diagram. I welcome comments from others who have used a similar antenna. How it compares with DKAZ would be the most relevant topic.
DHDL is a related type:
https://dh1tw.de/double-half-delta-loop-dhdl-receiving-antenna/
My biggest pests are the NYC stations about 200 miles to the west. There is mixed groundwave and skywave at night. The apparent arrival angles on the higher band stations such as 1130, 1190, 1280, and 1560 move around a lot. A proper DKAZ, an array of them, or Lankford's set-up would be just the ticket to get that big wide back null covering that wide spray-pattern of bounce angles.
With only about 100 ft. of east-west usable yard space, that just isn't going to happen here.
What I wind up with instead is likely to be the null-west SuperLoop, a null-north one, and one-frequency-at-a-time phasing during live DX to throttle down the persistent super-pests that just won't go away otherwise.
On the car roof, I used to phase a loop versus an active whip and I could get nulls much deeper than what the loop alone gave .. but only on one frequency at a time.
The Split Flag / Split SuperLoop designs might also be worth a look to see if reasonable gain and directivity can be mustered in a less-than-140 ft. length. The inconvenience of these typically requiring three tall supports may tend to rule them out for some.
http://www.qsl.net/wa1ion/pictures1/dual_feed_split_flag.gif
http://www.qsl.net/wa1ion/pictures1/dual_feed_split_superloop_38m_long.gif
http://www.qsl.net/wa1ion/pictures1/split_superloop_201709.gif
Mark Connelly, WA1ION
South Yarmouth, MA
Â
<<
Well here's something that's been on my mind lately, regarding
differences between superloops and the DKAZ:
It seems to be my experience so far that at night, the back and side
nulling characteristics of these antennas changes, due to sky wave vs.
ground wave, yes? Which one is more affected by those changes?
Mark
Goshen, IN
On 2018-10-24 1:42 pm, Chuck Hutton wrote:
> Mark -
>
>
> No arrogance detected here.
>
> Now back to the issue of DKAZ low band performance...?
>
>
> Chuck
>
>
> ________________________________
> From: IRCA <irca-bounces@xxxxxxxxxxxxxxxx> on behalf of Mark Pettifor
> <mark@xxxxxxxxxxxxxx>
> Sent: Wednesday, October 24, 2018 8:58 AM
> To: Mailing list for the International Radio Club of America
> Subject: Re: [IRCA] KAZ versus Pennant/Flag
>
>
> Apologies, Chuck, and to the rest here. In looking back at my post, I
> realize I could have said things a lot less arrogantly and put-offish.
> That's how I sounded to myself anyway after re-reading what I posted.
>
> 73,
> Mark
>
> On 2018-10-24 1:57 am, Chuck Hutton wrote:
>> Mark -
>>
>>
>> I suppose we all agree that the DKAZ has nailed some great catches.
>>
>> My goal was to point out a shortcoming, not to say that it can't hear
>> DX a la Colombia / Venezuela / Nicaragua.
>>
>>
>> Chuck
>>
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