I guess this didn't forward so here it is again.
Cheers,
Steve K7LXC
TOWER TECH
>> Today's Topics:
1. CONVERT 2 EL 40 CUSHCRAFT TO 3 EL?
2. Re: CONVERT 2 EL 40 CUSHCRAFT TO 3 EL? (Joe Reisert)
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To: <towertalk@contesting.com>
Date: Sun, 16 Feb 2003 21:50:29 EST
From: W0YR@aol.com
To: Antennaware@contesting.com
Subject: [Antennaware] CONVERT 2 EL 40 CUSHCRAFT TO 3 EL?
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Does anyone have experience with converting a 2 element Cushcraft 40 Meter
yagi to a 3 el antenna. Did you buy/build the coils? Spacing that worked
for u? Results?
Matching?
F/B Gain results? Bandwidth?
Mike
W0YR
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To: <towertalk@contesting.com>
Date: Wed, 19 Feb 2003 16:30:34 -0500
From: Joe Reisert <W1JR@arrl.net>
To: W0YR@aol.com, Antennaware@contesting.com
Subject: Re: [Antennaware] CONVERT 2 EL 40 CUSHCRAFT TO 3 EL?
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HI Mike,
I did some work on this conversion in 1990 for the late Jim Rafferty, N6JR.
I don't know if Jim ever did finished building it before he died.
I modeled the 3 element on a 33 foot boom using the same hardware as the
rest of the beam. As I recall, the gain was not very much greater (perhaps
1 dB) than the 2 element 40-2CD but the pattern improved quite a bit (as do
most Yagis on a 1/4 WL boom). Also, the VSWR degraded. One big problem with
this design is that the Q of the coils is so-so at best so adding another
element with the same coils also sees additional loss. I think they will
still sell them as replacement parts through customer service.
73,
Joe, W1JR >>
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