[BC] AM detection in teeth/fillings

[patrick roberts]

I used to work for a 50kw directional here in OKC.  Even though the fences
were grounded real well and tack soldered to the posts and had strap over to
the station ground, it still sung pretty good when shook a bit.

On this particular site there is a 80 foot STL tower in the major lobe of
the station.  Needless to say it caused problems with the array, so a detune
was installed to bring it out of the pattern as much as possible.  A
consultant came in and built the system and tuned it up.  I consisted of a
large box with a large bowl insulator on the side, a big cap inside the box,
and a skirt up the tower.  After he got everything working he went off with
the CE at the time to a cell site that they would later install another
detune at.  The CE's cell went off just after arriving at the cell site
which was about 10 minutes away.  The FM rock DJ called to say that the
tower out back was "on fire man!"  and throwing out sparks,
etc.  Considering the DJ that made the call the CE thought the tower might
have been crackling a bit... no biggie.  When the consultant and CE returned
to the 80 foot detuned tower they found blue and yellow blazes of singing
audio and flames blasting over the bowl insulator from the corrona ring to
the shell of the box.  They could hear it from the parking lot like it was a
PA speaker!  Needless to say a larger bowl was installed and the problem
ended.  Because of the high impedence of the detune tower there is a
tremendous amount of RF voltage there that will jump over pretty easily.

One time we had a problem with the 1940s model feed-though at the top of the
center/Day tower.  The wok at the top experienced a ice chunk that bent the
wok cap hat down close to the top of the ATU.  Needless to say I HEARD the
problem and saw it well before getting very close!  Wow was it MAD!

So has anyone else tried the glowing wand trick of holding a 4-foot
florecent light tube by one end and getting out in front of a directional
50k at night?  It doesn't take too much trying to get one of those suckers
to light up, at least at the former KOMA 1520.

AM can be so neanderthal! Fun times!

PR