GE BT-25 Mystery transmitter site

Update: Thank you, Jim.  The mystery site is KFIG (formerly KFRE) in Fresno, CA.  This is what the transmitter building looks like from the outside today:

KFIG transmitter, circa 2011
KFIG transmitter, circa 2011

In the previously mentioned rescued file cabinet and along with the WFLY transmitter site construction information, I also found these interesting photographs:

Mystery AM transmitter site
Mystery AM transmitter site, plate 9296

I do not know what transmitter site this is. From the photo, it has a two-tower (guyed) directional antenna. It looks to me to be somewhere out west. The transmitter is a General Electric BTA-25 or BT-25, the same as the former WPTR and WCKY transmitter. I know this back hallway well:

Mystery AM transmitter site, back hallway of GE BT-25.  Plate 9300
Mystery AM transmitter site, back hallway of GE BT-25. Plate 9300

This is the transformer vault:

Mystery AM transmitter site, transformer vault.  Plate 9297
Mystery AM transmitter site, transformer vault. Plate 9297

Modulation transformer and three-pot plate transformer:

BT-25 modulation transformer.  Plate 9299
Mystery AM transmitter site, GE BT-25 modulation transformer. Plate 9299

I would say that these may be promotional photos, because of the spotlessly clean installation and the plate numbers on each print.  Unfortunately, there are no pictures of the front of the transmitter, including the operator console.

Does anybody know where this is?

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17 thoughts on “GE BT-25 Mystery transmitter site”

  1. I see that you enjoyed reading the old BT-25 files as much as I did when I discovered them in Jim Cruise’s old file drawers. The site in the photo has a California or western look to it, so I suspect the station might well be the old KFRE 940 in Fresno, CA. I remember a “full frontal” shot of a rig with the KFRE call letters above it in the same file folder showing the control console and polished tile floor you could eat off of. They were all publicity photos taken by the GE Broadcast marketing department.

    When I was CE at WPTR 1540, I was in correspondence with the chief at WCKY who also had a BT-25A. He told me that we were in a very exclusive club with only WCKY, WPTR, KFRE, and possibly KGEI shortwave in Redwood City, CA having such rigs. I’ve never been able to confirm that KGEI ever had that model, but they did get a prototype GE from the 1939 Golden Gate Exposition and were loyal GE customers. Their GE rigs lasted them up until the day they went QRT in 1995. I read that the KGEI GE transmitter was later sold, dismantled, and shipped to west Africa where it was later destroyed by revolutionaries in a bombing.

  2. Looking at Google Earth, I see basically the same nice, little transmitter building. Perhaps slightly altered with an addition added since that promo shot was taken about 65 years ago. The station is now called KFIG. That’s a 4-tower array out back.

  3. Thank you, Jim. I searched around for the picture of the front of the transmitter, but it is gone. Too bad. I looked at the KFIG site on Google Earth, and that is indeed the site in the picture.

  4. This KFRE site was probably built as a consequence of the great NARBA frequency shuffle of March 1941. The only question is whether it was squeaked in just prior to WW2 or immediately thereafter once the war related restrictions on construction materials were lifted. It was obviously previous to ~ 1949 when WPTR got their BT-25A. WPTR had been using a RCA 10kW rig for a year or two until they purchased the BT-25A once Patroon discovered the ground conductivity was poor and were given a new CP for 50kW. I recall from the file that happened very quickly after sign-on, but prior to 1950. If anybody from Fresno lurks here, I for one would love to see some current photos of that site!

    Sad to say, all the BT-25 transmitters are now gone. I think WCKY still has an empty hulk, but the end finally came because of the high cost of insurance.

  5. Gosh, that’s a really attractive radio station building.
    No one has yet mentioned a particular year for the photos, but by the building styling it would seem to be somewhere in the mid-late 1930s when that style of windows shown was
    considered very smart and modern looking, along with glass block windows.
    Love the bolted on top of the transformer..looks like there’s 50 bolts!
    White stucco on the outside and still exposed brick in the halls is just so perfect.

  6. Anybody know what transmitter they’re running today? Solid-state, no doubt – perhaps a Nautel?

    I’m about 135 air-miles west of KFIG and pretty much out of their directional pattern, but can still pick them up, although the signal is weak…

  7. I suspect the photos are from 1947. I would not doubt that the KFRE site once had live-in staff given the landscaping touches and homey look about it. Many older sites reflect the pride that station owners once had in their transmitter facilities as well as some of the wonder that radio inspired in people at that time. There is a 1930’s era transmitter bldg near me that still has a public viewing gallery where people were once encouraged to visit and see a radio station transmitter in operation.

    I found a blurb on the Web that states the BT-25A was General Electric’s first 50kW transmitter badged under its own name. It may have been engineered pre-war, but the first unit likely was shipped in late 1946 or ’47. It looks like they were sold until 1963 with the last one installed at KCBS in San Francisco being called a model 4BT-25A1. That’s one site I had never heard of before. The replacement was the GE 4BT-50 which arrived in 1964. It saw several improvements right up until GE left the broadcast manufacturing business in the early 70’s. I believe that Harris purchased the assets of the GE transmitter business. It’s remotely possible that some documentation on these beauties may rest in a dusty archive in Quincy somewhere. A Harris field service engineer once told me that Harris has documentation for every transmitter that Harris and Gates produced going back to Day-1.

  8. “Sad to say, all the BT-25 transmitters are now gone…the end finally came because of the high cost of insurance.”

    Jim, what do you mean? Just general equipment insurance, or something else?

  9. PCB’s. These transmitter had loads of PCBs (GE trade name Pyranol) in the big transformers and capacitors. The insurance companies and banks holding paper required that the PCB’s be removed.

  10. Like the man said, it was mainly because of PCB’s in the transformer oil. The BT-25A had hundreds of gallons of the stuff, and most large electrical transformers contained it up until the EPA outlawed PCB’s in 1979. After ’79, but particularly during the great wave of consolidations in the ’90s, the banks and insurance companies became very risk averse. Business property premiums skyrocketed and policies were cancelled. That pretty much doomed the older big rigs. I heard of some being retrofitted with non-PCB capacitors and transformers, but newer transmitters were also much more efficient, required less maintenance, and had better specs. Replacement became a no-brainer.

  11. I had the privilege of getting a complete private tour of this transmitter site in the mid-1970’s. My friend was a buddy of the CE and we were invited to visit on a Sunday morning. In those days, this transmitter was put on the air for a couple of hours each week. The size of the modulation transformer was astounding to me. We even went out to the base of the tower, where we were able to listen to the modulation as it rattled the box. We watched the (manual) cut-over to the single-tube primary transmitter, which went from Zero to 50-kW in less than one second. As a relatively new Amateur Radio operator, limited to 1500-W, this was awe-inspiring. I’m really sorry to hear that this transmitter has been dismantled.

  12. Jim, the hallway with the GE back side looks like the old KFRE radio transmitter. I worked there during the seventies and I was out at Monson California usually every week with the chief engineer at that time who was Hal Torosian. This GE transmitter ran the length of the building and it also had a air plenum underneath for cooling and 2 cooling fans on one side of the building which blew air through the tunnel. On the other side through the glass there was a audio Transformer that they used in those days it must have been 12 feet high by 12 ft across.

  13. Jim, you are right about the KFRE transmitter site with housing facilities. They were also able to broadcast with a full control console from that site. It had a full kitchen and a shower.

  14. Just discovered this post and I have a funny story about this site… in 1980 I was working as a DJ at KFRE and Hal Torosian was our Chief Engineer. I was a young “wet behind the ears” 23 year old that was full of himself. On nighttime pattern I regularly got calls from Canada and New Mexico.. one time when Hal was doing some maintenance/troubleshooting we went to daytime pattern late at night and I got a call from Wyoming!

    Pattern change procedure used to go like this… song ends, dead air, walk across the room, change pattern, walk back start next record. I of course hated dead air so I would disregard and just change pattern in the middle of the song eliciting an immediate phone call and excited verbal thrashing from Hal about arcing and modulation, etc. I did this a couple of times before Hal invited me out to the transmitter site one late afternoon on my day off and I enthusiastically accepted his offer. When I got there he showed me around and then disclosed to me WHY he had invited me out there at that specific time… he wanted me there when we changed pattern to get a personal experience of what that sounded/felt/looked like when the relays switched over… and change pattern we did WITH MODULATION! …and from that day forward, while I would always go as fast as possible to keep the dead air to a minimum, I never changed pattern with modulation again! (I always appreciated his “educate/scare the cr*p out of me” approach instead of just having me fired!)

  15. Yes Dave Hal sure hated when you would change pattern in the evening full audio. It would light up that phaser box like you wouldn’t believe especially since that box was the Vintage one of the old GE transmitter and not up to date like the Gates transmitter was. In the mid-1970s when I was there with Hal we were doing a field strength test in the different areas and different Farm fields in the area. A engineering company was contracted to adjust the pattern because it was way out at that time. Hal an I had to change some of the hard coaxial 52 ohm runs to each antenna tower which there were 4 in total. Those were the days.

  16. KBOI’s GE 4BT50 had a “Mute” terminal that would kill the RF at I believe the oscillator buffer amp. Pretty amazing to see it go from 50 kw to zero in 500 mS (as the RF decayed). Just hope all the bias supplies are good. It was for the “Magnaphase” VSWR detector that came with our transmitter (but wasn’t installed until I found it stashed in a box). With the Mute controlled by the pattern change panel it would do it in 600 mS with no arcing in the relays.
    Prior to that they used a mechanical system that took 5 seconds to change pattern.

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