THE CONSTRUCTION OF KHOF-TV CHANNEL 30
SUNSET RIDGE – 1967-1969
By W.B. Marston
In 1964 we sold KQXR-FM in Bakersfield and moved back to southern California, buying a home at 1616 Bushnell Avenue in South Pasadena. My wife Leila had received her bachelor’s degree and a General Elementary teaching credential while we were in Bakersfield and now got a teaching job in South Pasadena, where she taught for the next eighteen years.
While in Bakersfield I had continued manufacturing French horn valves for various band instrument manufacturers along with my duties as Chief Engineer and part owner of the FM station. I had also made parts for FM transmitters and audio equipment manufactured by Teletronix Engineering Company, owned by an electronics engineer named Jim Lawrence. I had manufactured some RF hardware for Jim before we moved to Bakersfield in 1958 and his requirements had accelerated in 1963 and 1964. His business was outgrowing his small shop in Eagle Rock, CA and we got our heads together to start looking for a building large enough to accommodate both our businesses. This resulted in our joint purchase of an office-industrial building at 308 Monterey Road in South Pasadena. I moved in during September 1964 and continued manufacturing valves with three or four employees, as well as spending considerable of my own time designing and making transmitter parts and FM transmitting antennas for Teletronix.
Jim Lawrence had done a lot of engineering work for KHOF-FM, a radio station owned by a small church known then as the Maple Chapel in Glendale, CA. The pastor of the church, Rev. Ray Schoch, had conceived the idea for a Christian radio station in the early 1950’s, and after much tribulation and penny pinching had gotten the station on the air in 1955. It was through helping this station get going that I got interested in FM radio and resulted in our family’s six year sojourn in Bakersfield. By the early 1960’s Pastor Schoch had also become interested in television. There were no longer any channels available in Los Angeles so Ray got Jim Lawrence to look for alternative sites and channel assignments. Jim hit on Sunset Ridge as a possibility. It is exactly twenty miles east and at a similar 5,000+ ft. altitude as Mt. Wilson, where most of the Los Angeles TV stations are located. Jim’s engineering calculations indicated that from Sunset Ridge most of the Los Angeles basin except the northern part of the San Fernando valley could be covered adequately with a television signal. Looking east, it was also determined that the required signal strength could be radiated over the city of San Bernardino, and it happened that there was an unused channel assigned there. Jim engineered the application to the Federal Communications Commission and in due course (several years) a construction permit for channel 30 was issued with call sign KITR.
For the next couple of years Maple Chapel embarked on a rather unsuccessful mission to raise the funds to build the TV station. The name of the church was also changed to Faith Center. They employed a manager, Steve McDaniel, who then hired a secretary and a chief engineer, a Korean expatriate who didn’t even have the required FCC license. Steve spent most of the money they raised on his and his staff’s salaries, a jeep and some test and studio equipment. He got a high-priced engineering firm to re-engineer the application for higher power and signed contracts for over one million dollars worth of equipment that they had no way to pay for. After a year or two the church board was getting quite concerned about the progress (or lack of it) and fired Steve. The others quit. By this time Jim Lawrence had sold his company to a larger electronics company and moved to Costa Mesa, CA. We had sold our jointly-owned building and I had moved my operations to a leased building on Huntington Drive in South Pasadena. Because of my previous help on the FM station, the church board and pastor Schoch asked me to look over what they had done and advise them as to whether or not they should try to proceed with construction of the television station. I visited and flew over the transmitter site, which was a bare mountain top with only a bulldozed building pad.
I analyzed the engineering specifications and the various contracts they had obligated themselves to. Technically, television was almost a new thing for me at this time. When Jim Lawrence filed the application for channel 30, he had asked me “Bernie, how would you like to build a television transmitter?” I had not thought of it since, but after twenty years manufacturing french horn valves I was ready for a different challenge.
With some trepidation I told Ray Schoch that I would get a TV signal on the air for one hundred thousand dollars if he could just come up with the money as I needed it. He went to his congregation the next Sunday morning and they raised eighty five thousand dollars, so my activities for the next several years were decided. Ray Schoch did not preach his sermon that Sunday morning.
First I turned my attention to re-negotiating the contracts they had signed. They had agreed to pay RCA nearly one million dollars for a TTU-30 UHF transmitter, a TFU-30 Pylon transmitting antenna and various studio equipment. RCA was willing to sell the transmitter to another customer, as it could be fairly easily re-tuned for another channel. The antenna and an external transmitter accessory called a filterplexer were built specific to channel 30 and not readily resellable, so I arranged to apply the $10,000 down payment to those items for an additional obligation of $14,000.
There was a several hundred thousand dollar contract with Ampex Corp.for videotape recorders, which I managed to cancel completely. There was also a contract with Utility Tower Company for a three hundred foot guyed tower. There was really no reason for a tower that tall, but when it was designed they thought that they might rent space on the tower for other antennas. It was a rugged tower designed for ice loading anticipated over 5,000 ft. altitude, with provision for the heavy free-standing pylon antenna on the top. To avoid re-engineering the entire tower, which had already been approved by Los Angeles county, I simply cut it back to the first guy level at 95 feet, eliminating 200 feet of tower as well as two sets of guy cables with their anchors. This also reduced the cost by several thousand dollars.
Design work on the transmitter was then begun. Because I was not going to use a commercially built transmitter that was “Type approved” by the Federal Communications Commission, I would be required to file extensive plans, schematics and design specifications with the FCC before I could get the construction permit modified under a provision of the FCC rules that allows an installation to be “Type accepted” at a particular location. It is illegal to start construction of a television or radio station without a valid Construction Permit.
In 1967 solid-state devices such as transistors were just coming into general use. The exciters and low-power devices then in use in transmitters all still employed vacuum tubes. With one exception; George Townsend, an engineer in Massachusetts, had begun to make a name for himself by marketing conversion kits for the General Electric 12.5 kW UHF television transmitters that were then the most common in use. The Eimac Company in Palo Alto, California had developed a 25 kW klystron, then the most powerful UHF amplifying device available. If I remember correctly, this was an outgrowth of technology developed for “Dew Line” use by the military. At any rate, General Electric was adapting the new 25 Kw klystron into their new TV transmitters, and George Townsend came up with a conversion for the older models that added an extension to the rear of the visual cabinet allowing room for the larger klystron. He then added magnet power supplies and a new high voltage power supply. It was a clean installation and he sold a number of them. I assume that it was because of his success with the conversion kits that George decided to build entire UHF transmitters, and to this end he developed the first solid state exciters. The components were all discrete devices, as this was years before integrated circuits were available. The design was somewhat over-engineered and turned out to be nearly bullet-proof, as all the transistors were operated at a fraction of their published ratings. I negotiated with Townsend for the purchase of what was called the driver, which consisted of a large cabinet with double-rack swing-out doors, the visual and aural (picture and sound) exciters and visual modulated amplifier to drive the visual klystron, complete metering for the equipment supplied, and space for necessary monitoring equipment. Townsend agreed to a price of $8,500.00, a bargain.
A klystron is not a very efficient device, at least from the standpoint of electrical power consumption. It is a very good amplifier of radio frequency energy, in that ½ watt or so of RF input will produce 30 kW at the output, but the klystrons available in 1967 were only about thirty percent efficient. In other words; to generate 30 kW of RF power required about 100 kW of electrical power. The wasted 70 kW is dissipated as heat in a large chunk of copper on the end of the klystron known as the collector. The heat absorbed in the collector must then be removed by some sort of cooling system, usually a water-air heat exchanger.
The klystron I was most familiar with at that time was what is called an “external cavity” model manufactured by Eimac in Palo Alto. Eimac had been recently acquired by another company, Varian Associates, and Varian had developed a cooling process for high power tubes called vapor phase cooling. With the prodding of RCA who had guaranteed the purchase of a certain number of tubes, Varian had applied the process to klystrons. The vapor phase cooling process takes advantage of a physical phenomenon that allows steam at 212 degrees F. to carry many times more BTU’s than water at 212 degrees F. For example: to get rid of 70 kW of heat with water requires a water flow of about 65 gallons per minute, but the same amount of heat can be carried off by about ½ GPM of water turned into steam. I learned this on a trip to Palo Alto where both types of klystrons were demonstrated to me by Hal Yokela, who was for many years a systems engineer for Eimac. As I mentioned, I was not familiar with the steam-cooled tube; in fact I was somewhat apprehensive about them, but after a couple of hours with Hal in which I learned a lot, he said “There they are. We make them both. Take your pick!”. The Varian tube is an internal cavity type that requires a lot less work to replace. It comes pre-tuned to the channel and only needs minor tweaking to get it up and running. On the other hand, the Eimac external cavities have to be disassembled form the old tube, re-assembled on the new and completely tuned with a sweep generator, a process taking several hours. I also liked the idea of cooling with a ¾ HP water pump for the steamer rather than a 5 HP pump for the water cooled type. Also, RCA had committed to the steam tube for it’s new line of transmitters, so I figured it would qualify as “state of the art”. In fact, RCA continued to use their tube exciter for several years, so my combination of Townsend’s solid-state exciters with the new vapor-cooled klystrons resulted in the most state-of-the-art transmitter of it’s time. Townsend never used anything but the water cooled tubes in his transmitters. As a side note, I purchased three new klystrons in 1968 for $8,500 each. The same tubes were selling in 1988 for $48,000 each.
I was at this point ready to finalize the design and submit an application to the FCC for modification of the construction permit, which was granted in a reasonable amount of time, along with a change in call sign to KHOF-TV.
The driver was ordered from Townsend Associates and they supplied me with dimensions of their cabinet so I could order three matching cabinets built for the klystron amplifiers and the high voltage power supply, which had to produce 18,000 volts DC at about 9 amperes; a pretty hefty requirement. The separate visual and aural amplifiers were virtually identical. I had the cabinets delivered to my shop in South Pasadena where I was in process of phasing out the production of French horn rotary valves that had been my chief source of income for the past twenty years. The klystrons and the large cylindrical electromagnet assemblies that encased them were also delivered there.
Transmitter cabinets in So. Pasadena shop
I will leave the details of the manufacture of the transmitter for later and continue with the history of Sunset Ridge as a transmitter site. Utility Tower Company had begun construction of the 95 ft. tower in the spring of 1968 and RCA had delivered the TFU-30 pylon antenna to a meadow at the beginning of the dirt fire road that ran 9-1/2 miles from La Verne to the transmitter site. There was also access to the site from the other end of the fire road starting at the Cow Canyon saddle at the east end of the east fork of the San Gabriel canyon near Mt. Baldy Village. These two access roads we called the “front road” and “back road”. Though shorter (6 miles), the back road was rougher, more precipitous and more likely to be closed by snow in winter. We therefore generally used the front road although it too was subject to rock slides and washouts.
Utility Tower had brought out from Oklahoma a gin pole that I thought was too light to safely lift the 5,800 lb. Antenna. After erecting the tower they were ready to set the antenna, but I still had the problem of getting it to the top of the mountain. The antenna was basically a 50 ft. piece of 9 inch steel pipe weighing nearly 6,000 lbs. Thinking that a helicopter lift might be the most practical solution I started contacting helicopter services. It turned out that the only civilian choppers in southern California capable of lifting 6,000 lbs to 5,200 ft. were operated by L. A. Helicopters, a company that provided passenger shuttle service between airports. I found that they were only licensed for passenger service but their chief pilot, an ex-Marine, suggested that I talk to the Commandant at the El Toro Marine Air Base, since they had been known to do an occasional job of this nature. I called the Commandant and he informed me that he had just received orders that the Marines were not to do any more civilian jobs because the civilian helicopter operators had complained that the Marines were taking their business. He did suggest that I contact my Congressman to see if an exception could be made since I represented a non-profit organization and the civilian choppers could not do the job anyway. My Congressman happened to be on the Armed Forces Committee so I tackled that avenue. The result was an order from the Commandant of the Marine Corps to set up the lift as a training exercise.
Helicopter preparing to make the antenna lift Antenna on shipping trestles ready to lift
On the appointed day the Marine chopper arrived at the foot of the mountain, attached slings and started the lift. As Pastor Schoch, the tower crew and I watched we were horrified to see the antenna drop from a height of about 100 ft. I took off running toward the spot about a quarter mile away where the antenna had hit the ground. I got there as the Marine chopper was still trying to find a place to land.
The antenna was lying in a gully with the ends dug into the ground and bent about a foot, but the Marine’s lifting straps were still attached, indicating that the straps had come loose from the helicopter, not the antenna. The Marines picked up their straps and headed back to El Toro. A few days later they returned and moved the damaged antenna back to where they had picked it up. They blamed the drop on a defective release mechanism but I am pretty certain that someone panicked and tripped the electric release. Utility’s tower crew packed up their tools and gin pole and left.
It was a grim-faced crew that met later that day in a Claremont restaurant, but I was already thinking of ways to salvage the antenna. An RCA field service engineer was then in the air from Dallas to check the antenna before it was mounted. The next day I took him to the location of the damaged antenna where he pronounced it unrepairable. We had signed a release relieving the Marine Corps from responsibility. Very fortunately I had told Howard Skeans, the treasurer of Faith Center that the antenna was our property after it was unloaded from RCA’s truck and he had insured it. In fact, our insurance agent had watched it fall. The insurance company was offered $2.50 for it as scrap metal so they paid the $21,000 due for it and gave it to us.
Howard Skeans, church treasurer, at right
Grady Hughes, a Faith Center board member owned a steel fabricating business in Glendale and we moved the antenna there. Pastor Schoch made an announcement in a Sunday evening church service that I thought I could salvage the antenna and was looking for someone who could straighten large pipes. A man in the congregation came up and said that he worked for a company in Santa Fe Springs that fabricated large pipes for refineries and he thought that he could get the use of the company’s equipment. We loaded the antenna on Grady Hughes’ pipe dolly, hauled it to Santa Fe Springs, straightened it and hauled it back to Glendale in one afternoon. I repaired the damaged coaxial feed harness inside the antenna and checked the impedance. It was right on the required 75 ohms. Voila! Then it was back to La Verne on the pipe dolly.
Grady had an ex-army 6x6 truck with a crane mounted on it. He built a couple of saddles over the right side fenders and set the antenna on the saddles with the crane. It stuck out about fifteen feet on both ends of the truck. We made it to the transmitter site in a couple of hours, though having to back several times on the switchbacks and nearly losing the whole thing over the side at one point. The tower crew came back with a larger gin pole and set the antenna with no further problems. It served well for over 20 years and was only removed from the tower in the summer of 2000. (Note: I just received word that Grady Hughes passed away in Medford OR on Saturday, November 30, 2002, age over 80)
On the way up the mountain – Nearly lost the truck
After the tower was built, a 40’ x 42’ steel building was erected. I haven’t mentioned the problems of getting concrete delivered to a 5200’ site over 9-1/2 miles of dirt road. After delivering 26 cubic yards of concrete for the tower base and guy anchors the company refused to go up there again, so we had to find another transit-mix supplier to pour the building floor. Later I had to locate a third supplier to pour some additional concrete pads. I only got the county building inspector to go up there once and then I had to chauffer him both ways. He signed everything off sight unseen!
In the fall of 1968, with the building complete, including a small office , bunk room , lavatory and kitchen facilities we moved the Townsend driver cabinet containing the visual and aural exciters and monitoring equipment to Sunset Ridge with the Faith Center pick-up truck. We still had no power at the site and because of an unusually severe storm in November 1968 that washed out and blocked both roads we had no access to the site until the spring of 1969. Meanwhile I had plenty to keep me busy building the rest of the transmitter in my shop in South Pasadena.
Shortly after I first tackled the Channel 30 project I had contacted Southern California Edison about running power to the site. I was met with considerable disinterest because twice in the past three years Edison had been approached about this with an urgent request and had spent quite a bit of time and money designing a high voltage pole line from their existing power line coming through San Antonio canyon that supplies Mt. Baldy Village, but no construction had been started on the site. It was about 8,000 feet up a nearly 45 degree slope and they planned on setting poles by helicopter. By this time we had the tower and building on site and I was able to convince them that we were serious. They then decided to re-engineer and put the 13,000 volt lines underground. They wanted $26,000 for the job and a five year commitment for a 100 kW connected load, which was the approximate power drawn by our transmitter. We agreed to this and they accepted the $1,200 that had been previously paid as down payment.
Edison said that this was the first underground project of this nature that they had tackled. They contracted with Alex Robertson Company to lay the lines. As I mentioned, the roads to the site were closed because of the severe winter. Edison wanted to get going and sent in a bulldozer to open the back road, where there was still snow on the ground and several rock slides, but that road was shorter and not as steep.
About this time General Telephone Company got into the act. We had applied for telephone service and they decided to bury a 50 pair cable along with the Edison HV lines. A couple of weeks later they decided to make it a 100 pair cable. Then it was boosted to 200 pairs. We only needed one telephone for communication but they were looking ahead to more customers on the mountain. The only problem was that with the larger 200 pair cable there was less on a reel so it had to be spliced more often. They parked reels of cable at appropriate spots on the mountainside by helicopter. One reel got away and rolled all the way past the Mt. Baldy road thousands of feet down the mountain. They were very thankful that no cars were on the Mt. Baldy road when it went across. I think it was airborne at that point, though. That piece of cable was completely destroyed.
The Alex Robertson people brought in three Caterpillar tractors for the job. Two D-9’s and a D-6. The tractor operators were a little apprehensive about going down the 45 degree slope so the crew boss hopped on a D-9 and rode it down the 8,000 feet with a single ripper blade holding it back, digging down about three feet. Then they chained the three Cats together; a D-9 in front and back, the D-6 with a cable reel in the middle. They made four trips down the mountain this way; three for the HV lines and once more for the telephone cable.
Alex Robertson crew and equipment
The high voltage cable used was #2 aluminum conductor with about a ¾ inch diameter polyethylene insulation layer, then a black semi-conducting layer about 1/16th inch thick, over which was wrapped a spiral wire mesh. After the cable was buried and spliced it turned out that there was no continuity on two of the three wires, which had been stretched and broken. Time-domain reflectometry was used to locate the breaks with the one good wire used as a standard. Unfortunately, it had also been damaged and gave inaccurate readings, but the breaks were finally located and repaired. Alex Robertson had estimated six days for the job and it took six weeks. I think they took a bath on that one! Edison decided not to charge us the $26,000 and applied the $1,200 we had paid to the cost of the transformer vault A couple of years later they even refunded that. Their foresight paid off, as in later years that underground power line served four television stations and a number of communications installations.
During the winter of 1968-9 when access to the transmitter site was nearly impossible we continued to work on the rest of the transmitter at my South Pasadena shop where I designed and built the carriages and mechanism required to permit the installation and changing of the klystrons. The klystron magnet assemblies that form the “socket” for the klystrons were mounted on steel rollers running on a track assembly in the cabinets. With the back doors opened a frame with extension tracks was bolted in place, the magnet assembly rolled out and the klystron removed vertically with a small chain hoist. This was entirely different from the RCA design that tilted the magnet to a horizontal position and rolled it out onto a wheeled carriage. The RCA design used backless cabinets that required this approach.
The visual and aural amplifier cabinets housing the klystrons were completely assembled in my shop in South Pasadena.
Klystron amplifier cabinet partially wired
This included installation of meters, protection circuitry, relays, magnet and control power supplies and cabinet ventilation systems. I installed hundreds of feet of wire in the aural cabinet and Byron Mobus then copied my work in the visual cabinet.
Up to this time I was basically working alone on the project. The Utility Tower Company had erected the tower and antenna and Joe Baumgartner, a general building contractor had put up the building. Byron Mobus was then chief engineer of KHOF-FM and was of great help to me on the entire project. Grady Hughes, a Faith Center board member, was of tremendous help with his steel fabricating business as well as the use of his heavy equipment and trucks. He was called on several times to build special steel support structures that I designed for the heat exchanger, diplexer, etc.
With the road to the transmitter site now opened courtesy of Southern California Edison we moved the rest of the almost-complete transmitter cabinets to Sunset Ridge from my South Pasadena shop. Townsend Associates sent their field engineer Leroy Wallace out to check out their equipment. I hauled him up the mountain and back and he was apparently very impressed by the ride because he reminded me of it every time I saw him for years afterward.
Up to this time I had handled the project with occasional help from Byron Mobus and some of the Faith Center board members but now hired a young fellow named Fred Hoehn, the son of a long-time church member. Fred had obtained his “First ‘Phone” operator’s permit from the FCC and helped with some of the final equipment wiring. He became our first transmitter operator when we went on the air in October 1969. Fred did not have a lot of mechanical ability, often gluing stuff together with epoxy instead of mounting it properly. We came to a parting of the ways a few months after the station went on the air.
I had decided to use 5” diameter Andrew Heliax transmission line up the tower from the transmitter to the antenna. The 100 foot length could only be handled in a twelve foot diameter coil and I was faced with a difficult decision as to the best way to ship it to California from the factory in Illinois. It was finally agreed with Andrew Corp. that they would load the Heliax on a flat car with some other equipment they were shipping west and after some weeks I was informed that the flatcar with our material was sitting on a siding in Pomona, California and it was up to us to unload it and get it to the transmitter site. My first view of the task was more than a little intimidating. The crate with the Heliax in it was strapped vertically in the center of the flat car, measuring about 12 ft. x 12 ft. x 2 ft. That crate if laid flat was too wide even for the flat car. Fred Hoehn and I proceeded to tear the crate apart and discard most of it. I laid a couple of ten foot 2 x 4’s across the bed of a rented truck with the coil of cable laid flat on them, sticking out on both sides. We proceded with this illegal rig through Pomona and Claremont and up the mountain with no problems, fortunately not coming under the observation of any law enforcement people.
Heliax cable on flatcar in Pomona
Heliax and part of crate on rented truck – Pomona siding
With the transmission line now on hand, Utility Tower Co. sent out their crew with a heavy gin pole that easily handled the antenna installation and they installed the transmission line as well, after I fabricated some special elbows and impedance transformers, with Richard Bell in charge of the crew. Richard later formed his own tower company that I contracted with to install the tower for Channel 42 on the north peak of Mt. Diablo in northern California many years later.
Tower crew with tower sections and gin pole
The filterplexer that we had accepted as part of the cancellation of Faith Center’s contract with RCA was then mounted and connected. This is a device that consists of large coaxial components and tuned cavities that is used to properly combine the outputs of the visual and aural transmitters and feed its output to the transmitting antenna. I mention it here mainly to bemoan the problems we had with it. It was originally designed to work with a 10KW transmitter, but by pressuring it with sulfur hexafluoride gas it was re-rated to handle 30KW. This was a borderline solution and only a slight detuning in other parts of the system resulted in heat and damage to its components. A few years later it finally burned up so badly that we replaced it with a waveguide type of diplexer.
Original RCA Filterplexer mounted on stand built by Grady Hughes
Waveguide diplexer – same stand 2008
During the spring and summer of 1969 we proceeded with installation of the heat exchanger and plumbing for the klystron cooling system and the electrical components for the 18 kV power supply, as well as the other wiring to handle the 480 volt three-phase power and 120 volt needs of the system and building. We installed some old switching and monitoring equipment that was donated by KTLA and the RCA TK-26 film chain that we had purchased earlier from RCA’s television set factory in Indianapolis.
Sunset Ridge control room going on-air in October 1969
RCA TK-26 film chain and TP-16 projector
After making the final tests required by the FCC and applying for the license we signed KHOF-TV on the air in October 1969.
I am writing the last few paragraphs of this story in March 2010, a number of years after I started to write it as a record of the pioneering of Sunset Ridge as a transmitter site. In the years after the sign-on of KHOF-TV the site was also occupied by the transmitters of UHF channels 18, 56 and 62 as well as a number of communications repeaters on an adjacent hill. With the shutdown of analog television in 2009 the stations on Sunset Ridge were replaced by digital TV stations on Mt. Wilson and Mt. Harvard.
© 2010 W. Bernard Marston