[MAMS] How weather affects Tropo conditions

[Dr. Gerald N. Johnson]

When the proven one works well at 432 and has worked well for many 
others, any new method that gives different results must be in error.

Pfizbecke's classic NBS article also gave the first ever published boom 
corrections and his antennas were the first that gave claimed gain at 
VHF conferences and were repeatable taking the boom into account based 
on years of experiment on the antenna range before yagi analysis programs.

73, Jerry, K0CQ

On 1/9/2014 10:08 AM, Zack Widup wrote:
> 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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