The Moxon JK 40m is another way to go. Proven stack performance with
essentially the same design from modified CC 40m at K3LR. Really
wideband. Cheaper too.
An interlaced multi-band has to make some tradeoffs that yield lower
gain, poorer swr performance, or poorer F/B or some combination of all
three. Plus a lot more Al in the air and cost.
Then would you be better off with a long boom 3 or 4L at the top of the
tower? Do you intend do use the take-off angle select-ability of a stack?
Grant KZ1W
On 10/21/2020 11:07, john@kk9a.com wrote:
I believe Cushcraft coils have 68 turns of 12AWG wire. It is easy to
get SWR bandwidth with lossy coils.
The JK 2el Yagi should give you 2:1 SWRon the segment you require, I
have a couple of OptiBeam OB2-40 beams and I have no trouble covering
the lower phone band, RTTY and CW. Actually my SWR improves when they
are combined with a StackMatch however your 106ft tower may be too short
for efficiently stacking 40m beams.
John KK9A
cqtestk4xs wrote:
Plans are to stack two 2 2-element Yagis. I've narrowed it down to the
Cushcraft XM-240 and the JK mid-tri 40. Realize they are two different
approaches to the issue but I have lots of different ways to go. What
I am concerned about ...
First, I have spoken to Ken at JK and he assures me we can get less
than 2:1 SWR from 7.0 to 7.2. The Cushcraft's info says 250kHz for the
XM240. Also wondering if anyone has stacked these and what effect it had
on the SWR curve.
Bill K4XS
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