Topband: K9AY phased array

[K9AY]

Dave,

K9AY Loop users in desert areas have had more difficulty making them work 
well than most other users. Those that have done OK often use radials --  
typically 4 radials somewhat longer than the antenna footprint and placed 
under the loop wires, or perhaps 8 radials, the with additional 4 radials 
placed symmetrically between the others. The terminating resistance is 
almost always higher than the "normal soil" value of approx. 400 ohms.

In desert areas, flags and pennants appear to work readily. I'd recommend 
giving them a try. Tuned "magnetic" loops may also work well, especially 
when placed so a deep side null is pointed toward the TX antenna.

Proximity to a TX antenna is a problem for ALL receive antennas. Detuning 
the TX antenna during receive and protecting the receiver during transmit 
are very important for small-lot Topbanders! Radials have varied effect. A 
Beverage crossing a transmit radial system is an invitation to high level RF 
in the shack, possibly reducing Beverage performance -- although crossing 
just a few radials at a near-right-angle won't change the pattern much. 
Other RX antennas placed off the radial system, but nearby, may have strong 
coupling to the radial wires that are aligned with the antenna.

Hope this adds a little more info for consideration...

Gary
K9AY




> Hi
> I have been using a home brew K9AY loop on 160m for some time and have
> had similar (but not as bad) results as described by Dave G4GED. However
>  Mike WA5POKs comments have also got me wondering.
>
> I have been wondering what to do for an RX antenna in Bahrain (A9).
> Although I think I can erect a reasonable TX antenna, the plot size of
> my QTH is not excessive. It is also extremely dry, so I was interested
> in Mike's comments about watering. Not a good idea when water is more
> expensive than gasoline!
>
> My choice seems to be a K9AY which may not work too well because of
> proximity to the TX antenna and lack of a good ground or running out an
> un-terminated beverage type wire in a NW/SE configuration on the surface
> of the dessert common land nearby. This might however have to run across
> TX antenna radials.
>
> Any views?
>
> 73s Dave
>
/listinfo/topband