AM transmitter gets new tubes.

Just put a new set of tubes in the nighttime transmitter and used video to record transmitter readings. Trying to get with modern times, in an old way. Night rig is Bauer 702B, day rig is Collins 21E.

Category:

Science & Technology

Tags:

• tube
• tubes
• transmitter
• AM
• collins
• bauer
• 4-400

[douro20]

How old are those transmitters?

[paulshinn]

The Collins was installed new in 1955. I am told it is the oldest daily-use main transmitter in the country.

[ConservativeVic]

OMG-- Was that one of the Sparta TX that was a knock off of the Bauer 707? I didn't recognize the second TX. It sort of looks like an RCA, but I don't recall them using 4-400s. (But it does need a new thermocouple-- 0 RF current!) Vic, formerly with Orban

[paulshinn]

The small transmitter is a Bauer 702B. The large transmitter is actually 3 cabinets in all. It is a Collins model 21E running 5KW. Don't care about the RF ammeter in the driver cabinet you are referring to, the grid meter in the PA cabinet works and reads the current coming out of the driver cabinet just fine.

As for the 4 amp commenter- That is 4 RF amps. Into 50 ohms, that is 1 KW. The tubes are Amperex.

BossSound- Those are 4-125's in the driver cabinet of the Collins.

[Organgrinder010]

Very nice! That Collins is a 5kW transmitter, no?

[paulshinn]

Yes, it is a Collins 21E. It runs 5KW.

[kcscarecrow]

I worked on a Collins 21E when I was in college.

Back in those days we used the mercury vapor rectifiers which would glow blue violet and pulse with the voice or music beat.

[wa1ufo]

Real radios glow in the dark!

[SUPERDAVIDLEVINE]

I have never seeeen a worst video 240pand it jerks around and there is no noratio and they shhow such intersting stuff I could really learn a lot

[mpwelk]

@paulshinn station in my broadcast group used one of these until 3 years ago for 1550 madison (daytimer). engineer gave me one of the tubes as a keepsake!

[douro20]

If P=I^2*R, then 4 amps into 50 ohms would be 800 watts, but that's close enough.

Am I doing that right?

[VK3CSJ]

A nice transmitter for sure, it's a pity the video quality wasn't a tad better as non of those meter close ups had much value to look at i.e. to blurry never mind its still fascinating to look at this stuff!

Cheers

[rockangel1967]

this monster has about 10k on the RF? insane haha....

[504caveman]

i just love tubes thay are grate vierses transsiters keep them tubs gloing brigt as the son lat thare be rf herd all over yours trully gardner X einganeer TECK frum Carlsbad NM gardner J FUgate KE5njd aka 504 caveman

[mig189189189]

Awesome video. Keep on with that good work!

[nakayle]

Transmitters were much more interesting in the old days with bright glowing tubes- some of them water cooled, big modulation transformers and high-voltage mercury rectifiers that pulsed with the music. Visitors to the transmitter site were duly impressed. Now a days transmitters look like a row of filing cabinets with slide-out drawers of boring solid-state modules that impress no one.

[10TVMan]

Thanks for sharing. This brings back great memories of my first job out of college working at KPCO, 1370AM, in Quincy, CA ... 500 w non-directional daytime with an ancient RCA xmtr that was bought government surplus from a WWII ship. It was replaced with a Bauer 702B which we thought looked like a Coke machine compared to the massive RCA xmtr.