Topband: 4sq vs SAL 30 Mkii in a forest

Joe Subich, W4TV lists at subich.com
Mon Feb 18 19:44:25 EST 2019


 > Any experience with the same or  thoughts?

I would recommend looking into the YCCC "9 circle" (or "5 square")
array.  Even though the kits are no longer available boards appear
to be available from the PI4CC group.

The vertical arrays are less susceptible to wildlife damage than
the SAL (due to the low horizontal wire of the SAL) and provide
a higher signal level (before the preamp).

I like the YCCC design because it has a cleaner pattern than the
4 square (the center element is not "split" and thus does not
cause a spurious sidelobe response).  Further, the "9 circle"
version provides 45 degree pattern selection (vs. 90 degrees for
the 4 square) and if 90 degree steps are acceptable, the 5 square
version provides the higher RDF in the same space (60' diagonal
square).

As long as you keep the verticals (or the ends of the SAL) 10 - 15'
or so from tree trunks and keep the "brush' out of the array any
degradation should be minimal (mostly as additional losses) with
any of the antenna designs.

If you are comfortable with NEC (antenna modelling), I urge you to
run the models of all three designs and make your own choice.  Based
on the models, the SAL appear to be "unstable" and more prone to
environmental factors that the "amplified" vertical arrays.

73,

    ... Joe, W4TV


On 2019-02-18 2:56 PM, Mike Fischer wrote:
> Hi all, newb to the topband 160 reflector here so thank you for any coaching or corrections on protocol…
> 
> I live on a heavily forested (douglas firs - almost all of which are 100’+) piece of land.
> 
> I have enough room left to put up either an SAL 30 or a  4sq of 20’ verts with 80’ spacing. HiZ probably
> 
> Problem is regardless of which I choose, there will be at least one or two trees in the “infield“ and foliage around the edges.
> 
> Any experience with the same or  thoughts? Grateful for the coaching please feel free to reply direct to  mikebfischer at comcast.net
> 
> 73
> K7XH
> 




More information about the Topband mailing list