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RCA BTA 5F's where are they?

1

136kgb

Guest
How many of the RCA BTA 5F's are still in existence and are any of the still on the air? I know that there is still one of them in San Diego, but where are the rest.
 
Was that the 5KW Ampliphase? If so, there was one at the Cox AM in Birmingham for many years, first as the main and later as backup to an 828E-1 Collins. Dated back to the Hart - Hanke days.
 
The 5F was pre-Ampliphase. The 5F has 4 cabinets and weighs in at 10,000 pounds. The 5R/S/T/U lines were the Ampliphase models. The 5F went into production just before the War and stopped around 1952. The boxes are pure art deco in the design and the quality construction is unmatched.

RCA All The Way!
 
Maybe for old AM transmitters. There's an OLD 50kw in my market still on standby. Not for FM. Any FM RCA I encountered was pure danger.
 
LOL! I took care of a RCA 'fireball' series BTF-20 for years. We had a problem with it one time and actually went in and cleaned the hell out of the silver parts. Needless to say I think that's the reason that box is still funtional to this day. I always thought it would toast the building some day (I wouldn't have cried if it did. The building was lousy anyway.), but it never happened. For the most part it just kept running without complaint.
 
OK, pre Ampliphase. I had a BTA-250 in the same sort of cabinet years ago. Truly a work of art. And convection cooled in the bargain. It was the night TX for a class IV AM before the power increase. There was a 5 in Tulsa for some years as a backup... had the "Submarine Hatch" wheel by the back cabinet door which dropped a bar across the HV system before the door would open. The competing Gates (-5 and -5A) had the cast aluminum doors on air shocks and chrome bar switches on the front.

Perhaps one of the manufacturer's folks here can enlighten us... what do you suppose it would cost to build such a radio today? I bet you could cure cancer with that nmuch money.

It is interesting to look also at the other side of technology... in terms of real dollars, the 5KW you buy today probably costs something less than half as much, totally outperforms the old hoss, and requires maintenance which consists of cleaning the mouse manure out of the air filters as long as you feed it reasonably clean dry air and let it look at a reasonable load. And it is quicker to save itself should that load fail than the older ones.

I wish they looked as cool, though.
 
The BTA-5 R, T, and U's were not amplifuzzes. They were all plate modulated rigs. The U's and T's had a high efficiency PA circuit with a 3rd harmonic resonator claiming 90% PA efficiency. They used a single 5762 triode in the RF final, while the R used a pair of 5762's in a conventional Class C circuit. The ampliphase models were J's and L's I believe....anyone remember the BTA 5SS????

Lettin' it play on the big RCA!!!!


73's Bill
 
OKCRadioGuy said:
LOL! I took care of a RCA 'fireball' series BTF-20 for years. We had a problem with it one time and actually went in and cleaned the hell out of the silver parts. Needless to say I think that's the reason that box is still funtional to this day. I always thought it would toast the building some day (I wouldn't have cried if it did. The building was lousy anyway.), but it never happened. For the most part it just kept running without complaint.
Click to expand...

I swear I got most of my grey hair after working on the two RCA 20's at WASH-FM in the mid 80s.

I was on a ladder above one once, working on something else when I 'discovered' that high voltage was accessible from the top. No one warned me about that one!

Kind Regards,
David
 
I found the original engineering data for an RCA BTA 5SS it appeared to be not the easiest transmitter in the world to work on. Just so folks know yes the efficiency for the RCA's is terrible, but the fidelity being that they could handle 15khz audio for a BTA 5F (although the maunal would only claim 12khz). But the tube sound of the 5F is unmatched. We still have one in San Diego, and with very little effort it could be hooked back up and ran. As for the BTF-20Es those are some of the longest lasting well built transmitters in the world. If you clean and maintain the box it will last as long as you have parts. KGB-FM in San Diego ran one from 1964 or so until 2001. And the KGB-AM RCA BTA-5T ran from 1958 until 2001 both boxes were full time on the air. There is nothing especially dangerous about the BTF-20E as compared to any other box. Just show it the respect and use the dead stick where needed. The most dangerous box I ever encountered is the Collins Rockwell/Continental Power Rock 5kw with 15,000 negative volts.

If I had a choice of boxes to maintain on a regular basis I would take the RCAs hands down. For 2 years I maintained a TTU-60D which is the 60kw UHF TV box that is the same vintage as the BTF-20E. The most reliable transmitter in Texas was that RCA. The only thing that happened was the ITS exciter had all of the caps dry out on it so we had to get a loaner exciter, but the RCA itself never skipped a beat, but the 2 Harris's in the market were off the air more than they were on. The Harris boxes couldn't handle lightnening , but the RCA thrived on it.

But who out there knows where the RCA BTA-5F's are they made hundreds of them.
 
The 5F was a sweet TX. At one of the stations I worked at we moded the audio input network and then fed it with a pair of DAP310s in parallel with different time constants. Yeah, that was 1977, and AM rock radio. But it was sure sweet sounding. :)
 
If my memory serves me right, these rigs were RCA brown and had sliding doors. Both 790 and 920 in Providence, RI had them for aux transmitters into the 1980's, but I have no idea if they are still there. They do sound sweet, though being high level plate modulation, don't pin the peg like newer units do.
 
But as I remembered them, they had a warmer, almost transparent sound to them even at high levels of modulation. Yeah, it wasn't as loud, (by perhaps 1.5 dB), but it just sounded good.
 
The RCA BTA 5F actually did not have sliding doors that was a later series that came in out in 1954 or so and only lasted 2 years do to the immense cost of the machining of those doors. And the RCA color is not brown it is "umber grey" and the 5F's interior was painted silver and was light and dark umber grey with a black base and stainless steel strips. Damn Sexy true quality craftsmanship! By the way there were over 40 shades of umber grey over the course of RCA's use of it.
 
No.

136kgb said:
The RCA BTA 5F actually did not have sliding doors that was a later series that came in out in 1954 or so and only lasted 2 years do to the immense cost of the machining of those doors. And the RCA color is not brown it is "umber grey" and the 5F's interior was painted silver and was light and dark umber grey with a black base and stainless steel strips. Damn Sexy true quality craftsmanship! By the way there were over 40 shades of umber grey over the course of RCA's use of it.
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Pre 1960 RCA transmitters came in both brown and gray. As an example, here are two BTA-1MX transmitters. One is gray, the other brown.

http://webpages.charter.net/wd4tc/photo.htm

Another example of RCA brown:

http://www.hawkins.pair.com/rci/rcirca01.jpg

In the late 1960s, they got rid of both colors and changed to a, blue color.
 
Please note that the color you are still referring to in those pictures is umber grey! The only time a different colors offered was during the time of the BTA-1R and BTA 5R/S/T/U and that was different colored doors (red, or umber grey or blue). Then the next color change was in 1962 with the "New Look" when they went to Shadow Blue and Midnight Blue. If you don't believe me look in the original RCA catalogs the colors will be only Umber Grey, or red, or black, or for "new look" Shadow or Midnight Blue. The 1930's transmitters were gloss black. The pictures you showed were of RCA Umber Grey boxes there were over 40 shades of Umber Grey! I have complete catalogs of transmitters including the ones in your web links and the books show Umber Grey as the color not Brown! If the boxes look brown then someone needs to wash the nicotine off of them
 
Ah yes Dave Mason, I just had coffee with him this morning. Mr. Fybush I look at your site every week. Thank you for taking the time to do the site. You and Jim Hawkins do more to further our obsession than anyone else! Thank you !
 
Darn your web site!

I just burned up another 2 hours, Kinda like a time vortex.

I live a mile from the KOMO AM transmitter plant and I know they still have every transmitter they installed in that building. Starting with that RCA BTA50F. I need to get over there and take some pictures of it.
 
xmtrland said:
Darn your web site!

I just burned up another 2 hours, Kinda like a time vortex.
Click to expand...

You should see how many hours of my life get lost writing and researching the thing! :)

I live a mile from the KOMO AM transmitter plant and I know they still have every transmitter they installed in that building. Starting with that RCA BTA50F. I need to get over there and take some pictures of it.
Click to expand...

Me too!
 
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