[50mhz] Another Cushcraft Mod?

Tue Jun 30 15:15:48 EDT 2009

Collinears were in the ARRL, and Editor & Engineers Handbooks for decades as 
well as ARRL and CQ antenna manuals.

Each half of the driven elements are 1/2 wave with the reflectors about 5% 
longer. R to DE spacing is 1/4 wave and spacing between bays is 1/2 wave. 
Thats around 27' tall for 16 el on 6M.

The books will show the phasing and element mounting methods. I used a 1/4 
wave shorted stub of 600 Ohm line to match to the coax feed.

The collinear is very non critical of exact dimensions. I spent literally 
days trying to get any improvements using MN to optimize. Adding a director 
wasnt worth the effort either so I installed mine with the same dimensions 
as built by CC and just machined new insulators.

A collinear has roughly half the gain of an optimized yagi of the same # of 
elements. Its benefit is a huge azimuth and elevation pattern which makes 
them ideal for aurora, meteor scatter, rapidly shifting E skip, and 
contesting. Having a good yagi helps also.

I had the 16el 6M fixed on Europe for several years before I installed 4 
high stacks for 10 & 15M on that 100' tower and needed the real estate. It 
used to amaze serious DXers such as K1TOL with its performance. It usually 
heard the DX earlier and lost it later than the big yagis. Lefty, BTW, is 
using a Wilson M-68 I redesigned and sold to him.

Im hoping to reinstall both collinears on the side of the 180' tower with 
slightly staggered azimuths facing Europe and North Africa. Rotating above 
it will be a 4 bay box of yagis. It should be an interesting experience.

Carl
KM1H

----- Original Message ----- 
From: "J. Gordon Beattie, Jr., W2TTT" <w2ttt at att.net>
To: "'Carl'" <km1h at jeremy.mv.com>; "'Bill W5WVO'" <w5wvo at cybermesa.net>; 
"'Bill Aycock'" <billaycock at centurytel.net>; <50mhz at mailman.qth.net>
Sent: Tuesday, June 30, 2009 1:45 PM
Subject: Re: [50mhz] Another Cushcraft Mod?

> Carl,
> I had a 16 element collinear on 2m that was originally W2NCF's in Cedar
> Grove, New Jersey and it was a great performer!  I can only imagine what 
> it
> would be like to have one on 6m!  It was not a CushCraft, but entirely
> homebrew.  It was moved on top of my subcompact car (heavily flagged) at
> night about 2 miles to my home from his!
>
> Can you point me to dimensions for this type of antenna and perhaps the 2m
> one as well?
>
> Thanks & 73,
> Gordon Beattie, W2TTT
> 201.314.6964
>
>
> -----Original Message-----
> From: 50mhz-bounces at mailman.qth.net [mailto:50mhz-bounces at mailman.qth.net]
> On Behalf Of Carl
> Sent: Tuesday, June 30, 2009 2:29 PM
> To: Bill W5WVO; Bill Aycock; 50mhz at mailman.qth.net
> Subject: Re: [50mhz] Another Cushcraft Mod?
>
> Another CC design that is hard to improve on is their 16 el collinear.
> However since only 3 were built and Ive rescued and rebuilt  2 of them its 
> a
>
> moot point (-;
>
> One was built for Sam Harris, W1FZJ, and the other for Wayne Green who Im
> sure is known to all.
>
> CC wasnt the only company building 6M yagis by the seat of their pants. 
> The
> Wilson M68, Hy Gain 66DX,  and short boom 11 el Telrex were all in need of
> improvements.
>
> However with CC being just a long walk from here and HRO over in the next
> town, their local popularity is very high. Over the years there has been a
> steady flow of them brought in by owners for upgrades and tuning/testing.
> Getting extra elements, boom sections, etc, was as simple as driving up
> there.
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- 
> From: "Bill W5WVO" <w5wvo at cybermesa.net>
> To: "Carl" <km1h at jeremy.mv.com>; "Bill Aycock" 
> <billaycock at centurytel.net>;
> <50mhz at mailman.qth.net>
> Sent: Monday, June 29, 2009 11:24 PM
> Subject: Re: [50mhz] Another Cushcraft Mod?
>
>
>> There is not a whole lot you can do to a 3-element yagi. I've modeled the
>> factory design of this antenna and tried to improve on it using YO, but 
>> as
>
>> has
>> been said, it represents a pretty good compromise of the various factors
>> out of
>> the box. So I agree with Carl here. I wouldn't be inclined to mess with
>> it. Any
>> small improvement you might make wouldn't be worth the trouble.
>>
>> Having said that, you have to believe that this state of optimization is
>> blind
>> luck, since all the other Cushcraft 6m yagis can be significantly 
>> improved
>
>> using
>> computer-aided modeling and redesign.
>>
>> Bill W5WVO
>>
>>
>> Carl wrote:
>>> It will be interesting to see what you come up with.
>>>
>>> Thats another CC that I modeled when it came out and its just about
>>> perfect out of the box. The 2-3dB F/R improvement probably isnt worth
>>> the effort to make the changes.
>>>
>>> Carl
>>> KM1H
>>>
>>> ----- Original Message -----
>>> From: "Bill Aycock" <billaycock at centurytel.net>
>>> To: <50mhz at mailman.qth.net>
>>> Sent: Sunday, June 28, 2009 8:56 PM
>>> Subject: [50mhz] Another Cushcraft Mod?
>>>
>>>
>>>> Congrats to several who have improved the A50-5S, and those who
>>>> helped.  I have an A50-3S, New in a box (Not the original, I shipped
>>>> something else in it) I think I would like to model it, using EZNEC.
>>>> I am capable of building the model, but if anyone has one, I am
>>>> interested in saving the time. I will share my results.
>>>> Anyone?
>>>> Bill-W4BSG
>>>> ______________________________________________________________
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