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[TowerTalk] More CC 402CD -> 403CD

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Subject: [TowerTalk] More CC 402CD -> 403CD
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Date: Fri Feb 21 12:35:00 2003
Today's Topics:

   1. Re: CONVERT 2 EL 40 CUSHCRAFT TO 3 EL? (Joe Reisert)


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Date: Fri, 21 Feb 2003 09:54:27 -0500
From: Joe Reisert <>
Subject: Re: [Antennaware] CONVERT 2 EL 40 CUSHCRAFT TO 3 EL?
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HI Mike,

I have had others interested in the 40-2CD design so I will repeat what I 
also said to them.

The 40-2CD is a real toss up compromise design, BUT IT WORKS!

If you improve the unloaded Q of the coils, performance (mostly gain) will 
increase slightly. However, at the same time, the bandwidth may decrease 
since the losses in the loading coils will be less and losses can actually 
increase bandwidth!

The so-called capacity hats, the 36" rods just outboard from the inductors, 
help to increase bandwidth. Removing them will force you to increase the 
inductance of the loading coils or the length of the elements (or both) and 
will probably decrease bandwidth.

I am not the designer of the 40-2CD although I was very familiar with the 
design. The actual designer was the late Lester Cushman, ex W1BX. He did 
some of the design at his home in his backyard. As the story goes from what 
Lester told me, he was close to completion on the final design but needed 
more test time.

One Dayton HamVention weekend I think in April 1982 (Lester didn't go to 
HamVentions in his later years), he had the Cushcraft lab, equipment and 
motorized tower to himself. He worked feverishly all weekend testing 
different designs on the motorized tower and finally completed the design 
on Sunday afternoon after 47 different crank up and crank downs just as the 
motor failed! The following morning, when the normal design crew returned 
for the HamVention, they were infuriated that the motor on the crankup 
tower as burned out.....but now you know the rest of the story!


Joe, W1JR
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