Larry King wrote:

" When I first read this, I though you meant that you were ***inside*** of
the
diplexer [hopefully not while it was 'on the air'] :-) Then I reread it,
and understood what you meant. Yes those coaxial cavities can be quite
impressive.

KCOP does the 24/7 bit now as it did in 1958 when a buddy and I got
a tour of it. It was ON when we stepped into the collection of large-
scale plumbing. Not a problem.

I think my confusion stems from your choice of words :-) You equate
standing, walking, climbing, etc. in the open spaces amongst the coax lines,
cavities, etc. to being "in the diplexer" which I suppose in one sense is a
reasonable interpretation. I took your remark about being "in the diplexer"
to mean that you were actually inside one of the cavities during maintenance
or whenever it was not on-the-air ! You are correct, there is no absolutely
reason that you can't be in the immediate vicinity of all the components'
exteriors while it is in use [although you obviously would take great care
to avoid tripping over any cables powering fans, interlocks, reflectometers,
etc. as well as staying clear of any high temperature surfaces and generally
avoiding banging into or denting anything mechanical].

Two transmitters at right angles,
diplexer at the corner. At the time their older transmitter was on the
other side of the transmitter room, ready to use in case of main xmtr
catastrophe...forget how the antenna connection switchover was done
although it was explained

Probably a 3-1/8" coaxial line patch panel of some sort....either manually
operated or maybe motor driven with suitable interlocks.


Most TV broadcasters don't mind interested viewers visiting their
stations if one calls ahead. Remote transmit sites don't get a lot of
activity.

Well, times have changed a bit since 9/11. But you are correct in
principle, especially if you make the proper initial contacts in the
Engineering Dept (or what little bit is left of it at most stations). And
being a licensed ham always helps :-)

Mt. Wilson for Greater Los Angeles coverage is an exception
with over two dozen transmitters along with a solar observatory, a
couple hotel/motels, and the beginning of a national park area.

Always wanted to see it "up close", but I never have on my brief trips to
LA. Maybe one of these days ?

Len Anderson
retired (from regular hours) electronic engineer person

Former UHF-TV C.E. ("It's not a real transmitter if it's not water cooled
!")

I worked for WACX CH-55 In Orlando. Their first transmitter was an
RCA TTU-25B, and was replaced with a Comark 130 KW UHF transmitter that
you had to change the coolant and antifreeze twice a year. Later, I
moved the TTU-25B to Destin Florida, rebuilt it, and moved it to CH 58.
--


Michael A. Terrell
Central Florida