[Antennaware] CONVERT 2 EL 40 CUSHCRAFT TO 3 EL?

[Joe Reisert]

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

At 09:50 PM 2/16/2003 -0500, W0YR at aol.com wrote:
>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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