by

Bernie Marston CPBE

KHOF-TV Channel 30 serving San Bernardino and the Los Angeles basin was signed on the air in August 1969. The UHF television station was owned and operated by Faith Center, a Glendale, California church that had successfully operated Los Angeles FM radio station KHOF-FM since 1956. These two stations became the nucleus of Faith Broadcasting Network.

In assembling the composite Channel 30 transmitter for KHOF-TV I had purchased and used the solid-state exciters developed by George Townsend for use in his line of television transmitters built by Townsend Associates in Massachusetts. George had developed successful modifications and updates to the many General Electric UHF transmitters common at the time and then developed a whole new line of television transmitters including VHF models. It was about this time that the Ampex Corporation in Redwood City, California decided to expand into other areas of broadcast equipment to supplement their popular line of videotape recorders. To this end they purchased Townsend Associates and continued to build the transmitters in Massachusetts but under the Ampex name. To help publicize their acquisition and their entry into the TV transmitter business Ampex decided to support, and perhaps subsidize construction of a UHF TV station in the Bay Area to showcase their new purchase.   

My interest in UHF television had led me to follow the history of KUDO-TV, a station serving San Francisco and the Bay Area of California on UHF Channel 38. The station was put on the air in 1968 from a transmitter site on Mt. San Bruno just south of downtown San Francisco. Mt. San Bruno for many years had been the site of nearly all of the stations serving the Bay Area. Some of the stations had later built towers on Mt. Sutro and moved there. The huge 950’ self-supporting TV tower that has become a San Francisco landmark was at the time under construction, and all the TV and FM stations that could afford it joined a consortium to build, operate and maintain it.

Many years previously KRON Channel 4 owned by the San Francisco Chronicle newspaper had built a bomb-proof reinforced concrete studio-transmitter facility on Mt. San Bruno. They had later moved their TV transmitter to Mt. Sutro leaving only their FM station occupying the Mt. San Bruno building. Later certain parties had received a Construction Permit from the Federal Communications Commission to build a station on UHF Channel 38 serving San Francisco, call sign KUDO. They leased the unused area of the building on Mt. San Bruno including a three car garage, replaced the adjacent tower used by KNBR-FM with a sturdier one that would support a heavy RCA pylon TV transmitting antenna and contracted with Ampex to supply a 60KW transmitter, some VTR’s and other studio equipment. I remember several pictures of the installation in industry publications. The Ampex transmitter was installed in the garage area.

KUDO began operation on December 28, 1968 and left the air April 15, 1971 when the operator went into bankruptcy. Ampex repossessed the transmitter and VTR’s and RCA repossessed the rest of the studio equipment and the transmitting antenna. RCA left the antenna and transmission line in place on the tower. Bankruptcy Referee John M. England advertised the station including the FCC license for sale and set an auction date. News of the auction drew the attention of Faith Center Pastor Ray Schoch who persuaded the Faith Center Board of Directors to offer a bid of $10,000.00 if the amount could be raised independent of other operations. Pastor Ray and KHOF-FM manager Paul Calentine ran a telethon on Channel 30 and raised the money, so I shortly found myself attending bankruptcy court in San Francisco to place the bid. There had been rumors that several parties were interested but Faith Center’s was the only valid bid and it was accepted. When I contacted Mort Berfield, the communications attorney in Washington, D.C. who had handled previous dealings with the FCC for Faith Center he said “Hey, you can’t buy a bare TV license. You have to find some assets to support the payment and then the license can go along with it”. Actually, the only assets I found were a couple of microwave dishes. Everything else had been repossessed, but the FCC approved the deal and Faith Center then owned a non-existent San Francisco TV station. It fell to my lot to create one.

First, there were the legal details of transferring the license, with a change of call sign to KVOF-TV. The correct FCC application was prepared and submitted after the required community survey was completed and the transfer was approved on May 29, 1973. Paul Schoch, the brother of Faith Center Pastor and President Ray Schoch and the pastor of an Oakland, California church and his daughter Kathy Clarke assisted with the survey. Paul Schoch became manager of KVOF-TV when it went on the air in August 1974.

I first contacted the KNBR people and they were more than glad to again lease the building that they were making minimal use of. RCA quoted me a very reasonable price of $21,000.00 for the Pylon transmitting antenna and 6-1/8” copper transmission line that was still installed on the tower. Very fortunately Dale Harry, the KNBR Chief Engineer, had kept the line pressurized with nitrogen so it was in excellent condition. The building had earlier been used as a main studio so there was sufficient space to install equipment to put programming on the air.

Now for the transmitter. The three-car garage had been modified for installation of the Ampex transmitter. Wiring and plumbing trenches, heat exchanger sheet metal, electrical panels and a concrete pad for the heavy external power supplies were still in place. This all matched the Ampex (Townsend) transmitter installation of KUDO, but by this time Ampex had decided that building TV transmitters was not for them, so they had sold that part of their business to CCA Corp., owned by one Bernie Wise. I knew that we could save considerable time and money by using the same type of transmitter as KUDO and as was specified on the FCC license so I concentrated my acquisition efforts on Bernie Wise, though I got formal quotes from RCA and Harris Corp. Harris had recently bought General Electric’s TV transmitter business and was anxious to sell the transmitters that were already under construction so they could replace them with a new design of their own. They quoted a very attractive price and I was able to use it as leverage to get the transmitter I really wanted from CCA for the low price of $190,000. Having had a previous unhappy experience with a coaxial diplexer I agreed to pay an additional $5,000 for a waveguide diplexer. More on that later. A down payment was made and a contract signed that promised delivery of the transmitter in ninety days.

[Editor’s note: The diplexer referred to above is used to combine the high powered aural and visual signals to be sent up a single transmission line to the antenna at the top of the tower.]

Having completed lease negotiations with KRON for the transmitter building we waited impatiently for shipment of the transmitter from CCA. After the specified delivery date had long passed we were notified that the main elements of the transmitter had been shipped and at 8:00 AM on Wednesday, December 5, 1973 Steve Pair and I arrived at the Mt. San Bruno transmitter site where I was met by Rev. Paul Schoch, four volunteer Coast Guardsmen and four other of Paul’s parishioners. I called North American Van Lines and determined that the truck with the transmitter was in Sunnyvale, Ca, a few miles down the road. It arrived about 11:00 AM and we proceeded to unload the separate visual, aural and driver cabinets and move them into the building. I was surprised to find the visual and aural klystron magnet assemblies also on the truck as they were manufactured by Varian Associates in Palo Alto just a few miles south of San Bruno and I had assumed that they would be drop-shipped from the factory. Instead, they were shipped twice across the country (to Massachusetts and back).

The unloading of the magnets deserves a story of its own. The magnet assemblies for the particular type of Eimac klystron used in this transmitter consisted of a metal box about 4-1/2 feet high and 20 inches square mounted on four six inch diameter rubber-tired wheels to facilitate moving it in and out of the transmitter cabinet. The device was very top-heavy and weighed 1,600 lbs. The two magnets in crates were loaded in the front portion of the North American Van Lines truck, a fifth-wheel trailer with several feet of the front floor area raised four or five inches. While we were engaged in moving the transmitter cabinets into the building, the truck driver and his helper started to offload the magnets. Apparently not realizing how top-heavy the crates were, they pushed one of the crates off of the raised portion of the truck floor where it immediately tipped onto its side, hitting the floor with a crash that would wake the dead. We of coarse all rushed out to see what happened. I was very concerned that the fall had changed the alignment of the four large coils in the assembly and rather than unloading it, felt that it should be sent directly back to Varian for evaluation and repair. After carefully unloading the other magnet I escorted the truck to Palo Alto; the driver having been authorized by his company to follow my suggestion. I retrieved the repaired magnet on May 21, 1974, five and half months later at the same time we received the klystrons that go inside the magnet assemblies. So much for ninety day delivery of the transmitter.

When we got the klystrons and the repaired magnet on May 21 we did not get the tuning boxes (cavities)! Neither CCA or Varian would take the responsibility. When we finally got them on June 25 I had to reverse the tuning mechanism on the aural boxes; quite a job. “A lot of moving parts.”  

The acquisition and construction of KVOF-TV Channel 38, San Francisco, California, for Faith Broadcasting Network, 1972-74

In January an office was rented at 601 Taraval Street in downtown San Francisco for station manager Rev. Paul Schoch to conduct the business and promotional activities of the soon-to-be television station.

The two large heat exchangers for the transmitter were drop-shipped from the manufacturer and arrived in San Francisco February 19, 1974 and we proceeded with their installation; connecting the air ducts and power to the blower motors. Norm Bone, a licensed electrician, accompanied me to the transmitter site the following week-end where we ran the heavy cables to the power supplies and installed other conduit and wiring from the power panel to the transmitter. I was then able to obtain an electrical permit and get PG&E to turn on the power.

Crane lifting one of the supplies from the truck to the pad

One of the two 9,500 lb unitized high voltage power supplies

Final adjustments and testing were completed by the end of July and after making the Proof of Performance measurements required by the FCC the station was signed on the air on August 4, 1974.

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© 2012 W. Bernard Marston

Bernie Marston on a ladder in front of the waveguide diplexer with Joe Snelson perched on top

CCA transmitter installation with Leroy Wallace, CCA field engineer, making some final adjustments

Actually, the delayed delivery may have been a blessing in disguise. Installation of a television transmitter is a piecemeal process and this one was unusually so. I am reminded of the Heathkits for electronic instruments we built many years ago; a box of parts with a wiring diagram and instructions. This was like a HUGE Heathkit. Delivery of the various components stretched from the initial delivery of the cabinets in December 1973 to the last item, the diplexer, on June 24, 1974, nearly seven months later. The delay was a blessing in that it allowed me to continue with my regular responsibilities at the other Faith Center stations with weekly trips to San Francisco to work on the KVOF installation with minimum additional help as parts and other equipment became available. Joe Snelson or Steve Pair or both of them often came with me to work on the project, and Paul Hohman, a Faith Center Board member, was always ready to help in hauling and placing equipment. When we needed to stay overnight we went to a Howard Johnson motel in Redwood City, a few miles south of San Bruno, paid for by a trade-out agreement for advertising on Faith Center’s KHOF-FM station in Los Angeles. Joe Snelson and I still remember a night when we shared a room at Ho-Jo’s and at about 1:00 AM I heard a key turn in the lock and a stranger entered the room. I yelled “Hey, we’re in here!”, scaring the guy nearly out of his wits. The motel had double-booked.

As I mentioned, major components of the transmitter were delivered at various dates over a period of more than six months. The two large 9,500 lb. unitized high voltage power supplies arrived from HiTran, the manufacturer, on January 21, 1974. When I had been advised of their size and weight I had arranged for a crane to unload and place them on the concrete pad outside the building that had served the previous installation. They barely fitted on the pad. Bernie Wise of CCA had not used the same power supplies that Townsend/Ampex had used for KUDO. He just gave HiTran the voltage and current specifications and let them design the units; in this case for 480 volt three-phase AC primary power producing 26KV DC at 10 amperes, a hefty requirement. A unitized supply contains a transformer, rectifiers, choke and capacitors all in one large oil-filled tank, designed for outdoor installation.

A four cavity klystron

Klystron “dressed” with tuning boxes

Dressed klystron in magnet assembly

Early in March Joe Snelson, Steve Pair and I hauled the master control console, film chain and related equipment from Glendale to San Bruno in a rented truck. This was in the middle of the gasoline shortage of 1974 and to save the gas in the truck and avoid the long lines and minimum available rations at gas stations I rented a car at the San Francisco airport for us to use locally for errands and transportation to and from our motel in Redwood City. On the way back to Glendale we got the last gas from the storage tanks of two separate gas stations.

Larry Vosper, KVOF’s first Chief Engineer, seated at the master control console. This room was rather small as it was a former announcer’s booth in the early days of radio at KNBR

And so it went. With weekly trips from Glendale to San Francisco between March and June 1974 we proceeded with installation of equipment and related wiring, plumbing and testing. Some defective items had to be returned to the CCA factory for repair and we found several instances of incorrect wiring that we had to fix. Preparation and installation of the klystrons was also a major operation. Early in June we had nearly everything installed and checked out except that we were still missing the diplexer, the large complex device that connects the separate visual and aural (picture and sound) outputs to the transmitting antenna. I had agreed to pay CCA an extra $5,000 for a waveguide type of diplexer (a type that is almost bullet proof), but agreed to accept a coaxial type, less the $5,000, to expedite delivery, which was already several months late. We had no idea what would be the exact size and shape of the unit CCA was supplying, and when it arrived we found that it would not fit through the door of the building. We solved that problem by a partial disassembly of the unit and tilting it to go in the door. A goof by one of the riggers from the trucking company severely dented a section of 6-1/8” aluminum coax that I replaced with a section with 6-1/8” copper that I had at my shop in South Pasadena. We were then finally able to complete the transmitter installation.