Topband: K9AY loop still not working right, everything checked out OK though

[Michael Tope]

From: "steve d" <kc8qvo at yahoo.com>
To: <topband at contesting.com>
Sent: Thursday, January 12, 2006 5:57 AM
Subject: Topband: K9AY loop still not working right,everything checked out OK though

>>Steve,

>>Are you seeing and front-to-back on signals when you 
>>switch directions? That s the first thing you should 
>>look for.
>>
>>Mike, W4EF................................. 

>Mike, I am able to "turn off" most stations that I hear, only 
>ones that are real strong I cant get to go away. So I would 
>say that yes, I am seeing front-to-back. I probably do not 
>have the antenna tuned correctly though, but I am not so 
>sure that has anything to do with the level of noise that I 
>am picking up. 
>
>Steve, KC8QVO


Steve, 

The fact that you can make stations "go away" by switching
direction suggests to me that your K9AY loop has a decent
pattern. If it was strongly coupling into nearby objects, I would
expect that it wouldn't have much in the way of front-to-back,
although as I recall from computer modeling a tower next to a
K9AY loop, you can get into a situation where you have good
front-to-back when firing away from the tower, but no front-to-
back when firing towards it. In that case you might get a signal
to-noise improvement when listening away from the tower, but
when firing towards the tower, you would get no signal-to-noise
ratio improvement. The way to test for this is to listen for stations
coming from different directions to see if the array has decent
front-to-back in all four directions. In other words, if your listening
to a station coming from the east, do you get the same 
front-to-back rejection when you switch from beaming east to 
the west as you do when listening to a station from the the 
north when you switch from beaming north to the beaming 
south, etc. If the array only exhibits front-to-back on stations
coming from one particular direction instead of all four principle
directions, then that suggests that you have a coupling 
problem which could explain the arrays lack of noise rejection.

How far away is your TX antenna?

73, Mike W4EF............................................................