The Cushcraft design appears very similar to the 3 el 40 short beam from the
ARRL Antenna Book circa 1980. It was 3 elements on a 36 foot boom with the
reflector and driven element spaced 23 feet. It used coils with a capacity
hat on each element half. I think maybe it was Joe W1JR that told me in
about 1984 that converting to a 3 el was not really worth the effort. I
remember the figure of .8Db more forward gain and a sharper pattern.
I did lose one of the capacity hats on one reflector element half. At first
I noticed that the SWR
changed from mid band (7180 or so) to 7230 but little change in results.
The past few months
I now find the beam has lost front to back with beaming NW/SE its better off
the back by sometimes an S unit. Europe and VL/ZL are about equal strength
either was. I can keep the beam between NW and ENE and work about anything.
However I plan on replacing the hat. I have the actual pieces of metal for
the har. Just not sure if the clamp is still there (hard to see 87 feet
up). Ed K4SB says its a 2 meter element to boom clamp. Gotta crank down
all the amtennas. Health problems have kept me from doing the work until
I previously used a Mosley 2 el S-402 (the Cushcraft is much better) and a
Create 3 el HB9CV
on a 36 foot boom. Too flimsy and aluminum windings arced at over 1KW.
Seemed to work as well as the Cushcraft. The Cushcraft was compared to a
Telrex 3 el 40 on a 29 foot boom at N4RJ and was at least as good every time
(I would win 50% of the time). Val N4RJ then switched to a 3 el on a 46
foot boom and now he beat me at least 50% of the time.
A number of people told me my beam was a killer and bought their own beam.
K1MM told me his worked well on 17 and 12. I found the beam works very well
on 17 but on 12 its a cloverleaf pattern so its either boom or bust (S9+ in
JA and S3 in DU). The beam works on 160 too! It loads thru a tuner but
having the remote coax switch in line forces me to run 100 watts max. My
firsdt contact on 160 using the beam was HC8DX on SSB in 1987. I got a
59+20 and he had me confused with K4JPD. That was before I ran the remote
switch. I still use it on receive and the last couple of years used in
during the CQ 160 SSB.
I have not checked out the coil Q (so so according to W1JR). However it
makes a great 40 antenna for the little/medium gun!
73 Dave K4JRB
73 Dave K4JRB