MORE FM SERVICE IN NEW ENGLAND

FM Overcomes World's Worst Weather
to Provide Improved Programs in Rural Areas

The Yankee Network, in the spring of 1937, embarked upon a program designed to carry FM to practically all of the rural districts of New England, as well as the more thickly populated urban centers. The first step in this program, the erection of the Paxton station W1XOJ, has been described in FM Magazine.

The following is an account of the first phase of the second step, marked by the completion of W1XER, Yankee's FM station on Mt. Washington, N. H., highest point of land in the northeastern United States and home of "The worst weather in the world."

When W1XER went on the air December 18, 1940, it marked the inception of an interference free radio service to some million and a half potential listeners living in Northern New England. Most of these people could never have been provided with a really satisfactory radio service in any other manner,.as this is mostly a rural population spread over a large area. Once again, John Shepard, 3rd, has pioneered a new frontier.

Back in 1937, when Shepard became one of the prime moving spirits in Radio's Revolution, Yankee engineers under Paul A. de Mars, Technical Director, evolved a plan to provide 90% of New England with FM programs.

This complete plan involved the building of a 50-kw FM station on a mountain top at Paxton Massachusetts, and a 5-kw station on Mt. Washington in New Hampshire, and a 5-kw. station on Mt. Mansfield, in Vermont. It was estimated at the outset that the 5-kw station on Mt. Washington, with it's great height above sea level, 6,1288 ft., would serve an area similar to the 50-kw. station at Paxton, although the Northern New England terrain is extremely rough and mountainous.

Performance measurements have just been completed on the 1-kw and temporary antenna now being used, indicate that when W1XER goes to full power, it will have a service range of at least 75 to 100 miles, and, in some directions, notably the flat country of southeastern New Hampshire and southern Maine, the range will be considerably greater.

One of the most difficult problems Yankee had to overcome in order to build a station on the exposed peak of Mt. Washington was the weather. Dr. Charles Brooks, Director of Harvard's Blue Hill Observatorv, recently published an article summarizing his studies of weather on Mount Washington and described that climate as "perhaps the worst weather in the world."

Mt. Washington has the most severe climatic conditions of any mountain, regardless of altitude that has been visited by humans often enough to provide any sort of weather records. Mt. Washington has more severe weather than mountains in arctic Spitzbergen, other higher mountains in the Alps, or Byrd’s Little America in the Antarctic. Snow falls in every month of the year. During the winter months, the wind exceeds hurricane velocity (75 miles per hour) on an average of from 16 to 20 days each month. The world’s maximum wind velocity was recorded on Mt. Washington during April, 1934, officially clocked at 281 miles per hour. The writer has seen ice and rime formations (hoar frost) build out from exposed objects to a length of 4 to 6 ft., giving all structures on the Summit a most weird appearance.

It was at this bleak and inhospitable arctic outpost that John Shepard, 3rd, dared to gamble $35,000 in 1937. His engineers had told him that they frankly, did not know just how an antenna system would radiate when loaded with tons of ice and rime. They were not sure of the best way to design and operate an FM broadcasting station under such unusual and severe conditions. Accordingly, an experimental program was adopted. In 1937 a high frequency broadcasting station (APEX) was put in operation on Mt. Washington. Permission was secured from the Federal Communications Commission to set up a communication channel between the mountain and Boston. These facilities operated on a wavelength close to the present FM broadcasting wavelengths. An antenna was designed and constructed which, it was believed, would operate under the most severe conditions. An AM transmitter of 500 watts was installed in space rented from the Mount Washington Observatory in their new building. Storage tanks for 10,000 gallons of gasoline were buried on the side of the mountain below the Summit. A power generating plant was installed, and WIXER came into being.

The hardships encountered in the construction of this experimental station are almost undescribable. At one time, heavy rains washed out a good portion of the 8-mile mountain road, making it necessary to rebuild large sections of this road in order to transport necessary supplies and materials to the Summint. On another occasion, the tower foundation holes, 8 ft. square and 8 ft. deep, blasted from the immense pile of huge boulders that forms the Summit, filled with water after an exceptionally heavy overnight rain. Befofe they could be pumped out, the water froze. It was necessary to use live steam to thaw this mass of ice in order to empty the holes. Each morning, the ice and rime had to be melted from the structural steel by means of steam to enable the erection crew to start their work. Water for this steam, as well as for concrete mixing and living supplies had to be trucked up the Mountain 8 miles from the base. The steel crew was able to work only six days out of 18 spent on the mountain and then under exceedingly stormy conditions.

Construction finally had to be halted in November 1937, because of the severity of the weather. The 50-ft. fabricated steel section of the antenna tower was nearly completed and a single di-pole antenna was mounted on the top. This was the radiating system used by W1XER during the winter of 1937-1938.

During the summer of 1938. the tower was completed and an open -wire, 2-bay turnstile antenna was used during the next winter. Even though designed in the most rugged manner, this open-wire feeder system was unable to stand up under the constant battering of the elements, although it did provide a reasonably good communication circuit during that winter.

With three years of experience on Mt. Washington as a necessary prerequisite to the design and maintenance of any commercial 
venture, Yankee began construction of its FM broadcasting station in the summer of 1940. The following features were incorporated 
in the antenna design:
 1. Ability to withstand 300 miles per hour wind velocity, as well as several feet of ice and rime deposits.
 2. Radiating elements heavy enough to withstand the shock of hundreds of pounds of falling ice.
 3. A system that would radiate efficiently when completely encased in ice and rime many feet thick, without materially changing 
the circular radiating pattern.
 4. Flexability to operate over a comparalively wide range of frequencies. 

The supporting structure consists of 50 ft. of fabricated steel tower, made of excepttionally heavy steel. Above this rises a 44-ft. self-supporting steel pole 24 inchess, in diameter at the base and 14 inches diameter at the top. On this pole are mounted the heaviest of steel truck springs, each with a top leaf of 1 1/4 inch copper bar cut approximately 1/4 wavelength. These 1/4 wave elements, complete. weigh 360 pounds each and are capable of withstandmg almost any amount of shock from falling ice.

Each element is fed by a coaxial transmission line, terminating in an end seal directly under the spring, where it is protected from falling ice. A clamp makes contact with the spring at a convenient point about 18 ins. from the pole. The mechanical construction of the collars about the pole supporting the elements is so rugged and the collars necessarily so large, that they protrude some distance from the pole. However, by placing heavy copper over the collars and electrically bonding both halves together, the whole collar unit remains at ground RF potential as does the pole. The net effect is that the radiating portion of each element is that portion which protrudes beyond the collar. Accordingly, this portion is made approximately 1/4 wavelenghth long.

The lines feeding each element are brought down the tower separately, and all enter the transmitter building together, so that the power in each element can he controlled readily. This design is similar to the one so sucessfully used at Yankee’s Paxton station.

The transmitter building is temporarily the Mt. Washington Observatory building. Space is still rented in their building for transmitting equipment and living quarters. The close co-operation between this orginazation and Yankee has greatly simplified the many living problems arising at so isolated a location. A separate building to house the power generating equipment was constructed under the most severe weather conditions.

The writer awoke on the morning of August 24, 1940, to find that 4 inches of snow had fallen during the night. A 90-mile hurricane had blown this into drifts a foot or more deep about the foundation forms of the generator building under construction, and rime formations over a foot long were observed on the antenna tower. He has seen workmen struggle with boards and shingles on the roof of this building during 85-mile-per-hour hurricane winds, at temperatures not many degrees above zero, in a desperate effort to close in the building before real winter set in.

Some of the materials for this building and its associated power equipment had to be taken by truck part way up the mountain and then by tractor and sled over snow drifted up to 4 feet deep the remainder of the way. The building is ventilated in a most unusual manner. There are no windows, but air is sucked in through 600 3-in, holes made in the concrete foundation. Any conventional system of ventilation would soon become plugged with rime in the winter time.

The power equipment housed in this building consists of two General Motors diesel engine generators, one of 40-and one of 10-kw capacity. Additional space is provided for another 40 and another 10-kw machine to be added next summer.

Storage space is now provided for 25,000 gallons of fuel oil and 10,000 gallons of gasolene, in buried tanks located on the side of the mountain a short distance from the Summit. Remotely operated electric pumps convey the fuel to smaller tanks located in the power building.

Programs are supplied to W1XER from Paxton, Massachusetts, 140 miles distant. A standard FM receiver, with some additional RF discrimination, receives W1XOJ on 44.3 mc The output of this receiver is fed into the W1XER transmitter to be rebroadcast on 43.9 mc.

If, at any time in the future, it should become advisable to program WIXER separately, it is believed that this could easily be done by means of an FM relay transmitter operating in the vicinity of 150 mc.

During the last two months of the construction and testing period, it was necessary for the Yankee engineers and operating personnel to either ski or walk the 8 miles of mountain road to the Summit, because the snow made the road impassable even to a tractor. Some of the equipment late in arriving was taken half way up the mountain by ski-mobile, a contrivance with skis on front and tractor tread in the rear. It was back-packed by men the remainder of the way. A small amount of odds and ends were actually back packed the entire 8 miles.

During the winter months the operating personnel is isolated on the Summit for 4-week periods at a time. Each man of the staff plans to go down the mountain for one week, every four weeks. He cannot always leave on schedule, but makes the arduous journey down and back as weather conditions permit. It is necessary to transport, (during the summer, all food and supplies required for the seven winter months, as usually the road is impassable from middle October until late May or June. Yankee’s crew of two share occupancy of Observatory building with one Mt. Washington Observatory man and two United States Government Weather Bureau men.

At present, W1XER is operating with a power of 1 kw. Next spring, when the mountain road becomes passable once more, Yankee plans to begin construction of its own radio building. This will be large enough to provide living quarters for ten men, as well as to house the new transmitting equipment. With a power step up to the 5 kw. authorized by the FCC, and improvements in the antenna by the addition of more elements, W1XER should have an equivalent power gain of 16 by next fall, when this work will be completed.

The first two months of W1XER's operation have been very gratifying. Continuous re-broadcasting of Paxton's FM programs from a distance of 140 miles, has become an accomplished fact. Enthusiastic letters have heen received from listeners throughout northern New England, some from surprisingly distant points. Yankee engineers have listened in at most of the cities and towns within the estimated service area. Reception has been as good as or better than expected. even in many unfavorahly located areas.

A preliminary survey of coverage using a specially equipped field gear has just been completed. By means of an automatic recorder geared to the drive shaft of this car and a receiver equipped for recording, an ink trace of signal intensities along twelve radials has been obtained.

It is believed that all points within this area, excepting a few extremely unfavorable locations, are enjoying excellent service at the present time, and with the present low power.

There is no doubt but that this second step of FM pioneering in New England is destined to be an outstanding success.

FM/December 1940. A.F. Sise, C.E./Yankee Network