[TowerTalk] 40 meter Yagis

[Grant Saviers]

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 at 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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