[MAMS] How weather affects Tropo conditions

[Zack Widup]

I've used that before. As I mentioned, I am only interested in the recent
article. When I first saw the article I played around with it a bit and it
gave slightly different results than earlier methods. I wanted to try it
out and see what happens when I build an antenna using its method.

73, Zack W9SZ


On Thu, Jan 9, 2014 at 10:02 AM, Dr. Gerald N. Johnson
<geraldj at netins.net>wrote:

> The program ele.bas based on DL6WU data from G3SEK or now GM3SEK's website
> works for me. My last 432 yagis give more gain on the CSVHF antenna range
> than computed. Its been around a long time but DL6WU did it right. It is a
> dos program but I'm running it in XP using gwbasicwin.exe. If you can't get
> those from GM3SEK, I can put the on my server for a bit. I can't help for
> mac.
>
> The DL6WU technique is to make a two element yagi, reflector and driven
> element with an adjustable gamma match for the driven element. The mount
> the element length without boom insulated (like a foam boom) fairly close
> to the driven element, then tune the gamma for a perfect feed match.
> Replace the insulated element with the desired boom and element mount and
> trim the through the boom element until it give the same impedance match
> without changing the gamma. Using the two element yagi as a measuring tool
> for the reactance of the director being tested. And his antenna designs are
> based purely on a smooth distribution of changes in director reactance
> going from the driven element to the front director. They are not randomly
> compute optimized and so are most tolerant of length errors compared to the
> tightly optimized yagi where the optimization may have gained a dB of gain
> at the cost of higher side lobe amplitude.
>
> 73, Jerry, K0CQ
>
>
> On 1/9/2014 8:57 AM, Zack Widup wrote:
>
>> That would be very interesting! Let me know if you find it.
>>
>> There's something I've been looking for, too. I recently saw an article in
>> a proceedings or compendium that gave a way to calculate element length
>> correction factors for elements going through metal booms. I have seen
>> other articles on this but I only want the article that has been in a
>> proceedings or compendium in the last year or two. Maybe one of the recent
>> ARRL antenna compendiums? I just can't remember where I saw it.
>>
>> 73, Zack W9SZ
>>
>>
>>
>>
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