RadioBanter - Bird Brained Question

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Richard Harrison wrote:

Tim Perry wrote:
"---this is a very old array built in 1949."

In 1949 I worked at the KPRC (950 KHz) / KXYZ (1320 KHz) plant at Deep
Water, TX.
They shared a main tower which was built for KTRH (740 KHz), which had
moved to Cedar Bayou. The tower was near 1/2-wavelength at 1320 KHz and
a high impedance for both stations.

One operator responsibility was periodic logging of tower currents. For
lightning protection, the RF ammeters were shunted with knife switches
which must be open during reading. Since the main tower was so hot at
its feedpoint, we had a wooden stick with a bent nail in one end to
operate the knife switches. RF burns are unpleasant. This stick would
burn a carbon trail to your hand in a couple of weeks and be replaced.
The sparks along the carbon trail were spectacular but benign if the
stick was replaced soon enough.

Best regards, Richard Harrison, KB5WZI

I worked at KWLO in Waterloo, IA back in the late 70's. It was only a
5Kw station with a five element directional array. During the day only
two of the towers were fed and the night time pattern used all five.

During my initial instruction on how to read the current meters at the
tower bases, the chief engineer was showing me how to put the meter in
the clips and then rock the shorting bar out of the parallel clips that
were in the circuit. One side of the shorting bar was always in a clip.
then you would read the meter and put the shorting bar back into the
clips. After that you could remove the meter.

Well, he was behind the transmitters and the phasing cabinet in a fairly
confined space showing me how to do the task. Set the meter in place,
rock the shunt out of one clip, take the measurement, rock the meter out
of the clips.

How many of you caught the problem in that sequence?

Yup, that is the way he did it. The arc from the clip to the current
meter made the prettiest ohm sign I have ever seen. I saw the engineer
starting to rock the meter and was already moving away when he broke the
connection. The relexes of youth are a wonderful thing.

The only thing that happened to him was that he banged the back of his hand
on the inside of the cabinet as he got it out of the way of the arc.

The transmitter didn't even miss a beat on that little shenannigan. It
may have shown an overload on some of the warning lights but I can't
recall right now.

So, that's their excuse.

"Tdonaly" wrote in message
news:20040623235522.19052.00000561@mb-
There seems to be a general belief, around here (Belmont CA), that the
changing
magnetic
fields from power lines retards children's development and lowers their
collective IQ.

On 23 Jun 2004 12:17:49 GMT, in rec.radio.amateur.antenna you wrote:

For the first time in many years, I'm about to put up a 20 meter monobander on
a tower. The XYL is asking questions I cannot answer, specifically relating to
RF and birds. I wouldn't want to be a bird sitting on an element when a KW is
supplied to it? Are my concerns valid?

Some where around here I have several photos of Cormorants (I think
that's how it's spelled) sitting on the beams. Those are *big* birds
and it shows in the droop of the booms and elements. They didn't seem
to be concerned about 1500 watts.

I couldn't get rid of the darn things. They had decided that was
where they were staying for the night. When I'd chase them off they'd
just come back. Worse than a load of ice. They are bigger than ducks
and there were 8 or 10 of them up there.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Gary K5QT

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com