Topband: K9AY over rocky ground

Jeff Maass jmaass at
Sat Feb 10 08:49:09 EST 2007

> -----Original Message-----
> From: topband-bounces at 
> [mailto:topband-bounces at] On Behalf Of Björn Mohr
> Sent: Saturday, February 10, 2007 5:19 AM
> To: 'Topband'
> Subject: Topband: K9AY over rocky ground
> I have a K9AY that I would like to try at my mountain QTH. I 
> am on the top where there is little or no soil, just bare 
> rock. I have seen references to using the K9AY over rocky 
> ground using 4 radials laid out on the ground.
> What kind of performance should I expect in a situation like 
> this? How long radials should I use?
> 73 de Björn /SM0MDG

G'day Bjorn:

On Curacao, at PJ2T, the soil is a few inches
deep over coral rock, I was not happy with the
performance of a K9AY installed over twelve
30-foot radials.

In January, we installed (Field Day style) a 
DX Engineering 4-square RX antenna system. The 
active vertical whips require ground, and we tried
six 30-foot radials under each. In this case, the
antenna worked very well for us, providing amazing
front-to back (nulling out the USA to allow us to
hear South Americans better.

The bottom line is that you cannot know how the 
K9AY will perform for you in your environment
unless you try it. "Any RX antenna is better than
no RX antenna", and "More are better".

We migrated to flag/pennant RX antennas in place
of the K9AT at PJ2T, which have proved over the
past several years to work well over the lousy
ground, as do our two permanent Beverages.

73,  Jeff  K8ND

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