|[AMRadio] Wiring issues for BC-1T|
cemilton at aol.com
cemilton at aol.com
Wed May 9 20:04:15 EDT 2007
I've been reading the Gates BC-1T manual and found two instances where
they state that #4 wire should be used. One says:
"3) ...provide #4 or larger primary wiring from entrance box to
The other is about carrier shift at 100% modulation:
"9) Carrier shift: 3% or less between 0 and 100% modulation provided
wire size in point 3 (above) is followed..".
They have got to be kidding! Of course I know this is assuming
possibly 24/7 commercial operation at the full KW, but still, #4 wire
for a 1000 watt tx, PEP of 4000 watts w/100% modulation?
What the heck am I missing here?
I don't think you're missing anything.........but would suggest you
step back into the time frame when transmitters like the BC-1T were
1. Wiring insulation was a factor...............It's better today than
2. 1Kw and .25kw Bc transmitters were spread out over the USA and it
was the small towns/rural communities that had "local" radio stations.
Often, the transmitter was out in the country and often at the end or
near end of a transmission line. Voltage "sag" was a real issue.
Dimming the lights at 100% modulation wasn't a joke. Some engineering
was done by a local electrician whose total experience level was
connecting the chicken house to the main barn with two wires. No
disrespect here, but just the truth.
3. I worked at a 5kw, 5-tower directional on 590kc (Collins driver and
linear) and the transmitter was located in a rural county setting
literally at the end of the line as far as AC was concerned. We had
the power company locate pole pigs on a stand directly behind the
transmitter building. The idea was to have as much voltage and current
as possible as close to the transmitter as we could.
Like your suggestion, we tied the mains directly to the transmitter and
amplifier through a breaker panel with one humongous (sp) switch.
Leads were as large as possible (I don't recall the gauge) but were
short by most standards due to the pole pigs being located within a few
feet of the transmitter. IR drop, etc..........
By ham radio standards, you probably don't need all the "punch" that
Gates and other manufacturers recommended. That said, I would wire the
whole shebang with the largest wire I could afford. Just keeping in
mind the rest of the AC transmission system from the power company to
the breaker box in the house (and beyond).
Hope this helps. Best of luck with a great old transmitter. We all
want pictures when it's done. Preferably with the tubes lit and the
background lighting subdued.
73 de W4MIL
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