View Single Post
  #5   Report Post  
Old October 13th 04, 07:46 AM
Bill
 
Posts: n/a
Default

In message , Paul Keinanen
writes
On Wed, 13 Oct 2004 05:17:47 GMT, Rick Frazier
wrote:

er... these articles didn't happen to originate around April 1 did they?


Bill wrote:


many years ago I read a very good article on the "rusty bolt effect"
that went into great detail, even as far as warning about corroding coke
cans in the undergrowth.


The rusty bolt (intermodulation) problem can be quite severe e.g. with
repeaters in a commercial site with lots of high power transmitters.

Are the coke cans made of iron ?
Anyway, there would have to be a metal to metal contact that has
oxidised in order to have this kind of junction problem, so I do not
understand how thrown away cans could normally create such junctions.

It was maybe 20 years ago that I read this article so I am a little
vague on the details but I seem to recall that it was a build up of
coke, drinks, cans that was a problem. So yes it would be metal to metal
contact.
Another problem it highlighted was the effect of guy ropes. Where a guy
rope is cleated and anchored there is often a short piece of the rope
left over that runs either beside the guy or just hangs there. Not a
problem if it is rope but if it is a wire guy then you can have a 1/4
wave aerial immediately attached to a corroded junction.



Paul OH3LWR


--
Bill