Just in case some of you haven't seen such and are curious.
Here's a horrifying photo of me, holding a worn out 4CX15000A PA tube from my employers RCA transmitter for a 100,000 watt station. Now, the transmitter only puts out about 22,000 watts, the rest is from the gain of the antenna.
This bugger runs about 8000 volts at 4 amps when in operation. As you can see this has been in service for about 3 years and was losing emission, so I replaced it. Just in case you've never seen a commercial radio transmitter tube.
TIB
Tim, that tube looks like a radical cooker device from late night TV selling channel.
It is too beautiful to throw away.
Ditch the family photos and put it on the living room mantle.
Looks like an old slide projector.
a piece of NASA hardware orbiting Mars.
Brooce Part 15 Hartford
A broadcast engineer and a great friend
has taken me with him on his technical
travels on and off for many years.
A long time ago he took me to WBIS,
Bristol, CT - - 1440 kHz - - a 500 watt
daytimer.
To be continued. (Sorry gotta go.)
Brooce Part 15 Hartford
That was the final tube used in the Rockwell-Collins 831G-2C I worked on at KIOC (106.1) in Orange, TX back in the late '70s!!! 2 4X250A's were used in the driver stage; the exciter was solid-state (IIRC, 50 w. max output....).....The tube I ended up swapping out had sat UNUSED for about 2 years....Not knowing about recommeded filament "burn-in" time I put it right into service.....42 hours later...BANG!!! The ceramic element had cracked down one side!! New finals were going for about $8000 at the time -- rebuilts about half that...my boss (who drove a Mercedes--as did his wife....!) opted for the rebuilt. It was NEVER able to achieve 100% power (about 92%).....but we were at least legal (+5%/-10%)....
Sometimes I joke around and say I have
to leave the site and run off - - it's usually meant
for humour or is some kind of exageration. (sp?)
Last night I really had to go.
Anyway we were at WBIS 1440 500 watts
day only, Bristol CT. My buddy had just put 2
out of the box replacement final tubes into the
transmitter. He hit power on and then hit the
plate voltage ON button. Tim - - the tubes sort
of looked like the one you were holding but were smaller.
Soon after the plate voltage came on - a bright red dot
appeared in one of the tubes. I'm guessing it was an imperfection
in the plate. The dot got brighter and larger. Before things got
really bad my friend shut everything off. Then he
put in some other tubes and everything was OK.
The bad tube went back to where it came from.
Factory? I don't remember. I like talking about this
sort of thing. It was a long time ago. Fun. It really was.
Brooce Part 15 Hartford
now they can fit about 2kW in a solid state palet smaller than that tube.
Yeah, that makes you stop and think!
Brooce Part 15 Hartford
As Brooce said: "Yeah, that makes you stop and think!"
Well, I have stopped. But for some reason I'm not thinking.
The transmitter this came out of is scheduled to be replaced probably within the next year. We've done about all we can to keep it running. Parts are getting harder to find -- RCA quit supporting it years ago. It's lived it's life. It's been running 40 years or so.
The replacement is about 1/4 the size, and most of the insides are air!
TIB
LOL!! BE's AM-1A (1 kw AM) - WITH TUNING UNIT! - weighs 90 lbs. .....and fits in a 19" rack..
With room to spare!!:D