RadioBanter - View Single Post

May 10th 06, 04:56 AM posted to rec.radio.amateur.antenna

On 9 May 2006 20:43:50 -0500, wrote:

So the question remains: are J-poles sensitive to nearby materials?

yes, and also, RF doesn't always saturate an area.

The wire in the j-pole is affected by the insulating material the twin
lead is made from. Different types have different dimensions for the
j-pole lengths.

Though it doesn't make sense sometimes, moving an antenna near a wall
may cause a negative effect. I have that problem at my kids house.
They are hams and I setup a hook in the ceiling to hang a pole. It
worked, but their mom didn't want it hanging so far from the wall and
moved it against the wall. It doesn't work. So we found a compromise
spot near another wall, a corner actually. It works but it is leaning
at about 20 degrees coming from the corner.

There is also a problem of RF holes. Mobile operators and HT or
portable operators experience them the most. It is the cause of
picket-fencing. The mobile moves from a hot spot to a not-so-hot
spot. A portable rig can usually find the hot spot or the dead spot
easily. I can hit the local repeater from inside my room with low
power on my ht. outside about three feet away, I can't hit it on high
power. It is further from the wall there.

Good luck
Buck

--
73 for now
Buck
N4PGW