Amateur Radio Stations
December 1935 QST Article
Those of you who are not particularly interested in old electronic equipment will please indulge those of us who are. I post these articles occasionally to remind people of from whence we have come. Whether you are an amateur radio operator or just a cellphone user, appreciation is due to the pioneers who took the metaphorical arrows for us so that we may enjoy the micro-size, low cost, high quality communications available today. The full-height equipment racks in the photos were standard fare in the 1930s for long distance (DX) shortwave operators - often only for CW (Morse code). "User serviceable parts inside' was the rule rather than the exception. As much as I like waxing nostalgic over tube-based hardware of yesteryear, I am quite grateful to be typing this note on a computer keyboard and not on a massive teletype machine.
December 1935 QST
Wax nostalgic about and learn from the history of early electronics. See articles
QST, published December 1915 - present. All copyrights hereby acknowledged.
Amateur Radio StationsW2CBO, Scotia, New York
A. Lash of Scotia, New York, is the man behind the key at W2CBO. His first license, under the call W8CQS, was issued in 1928; moving to New York in 1930 brought W2CBO.
The transmitter shown in the photograph consists of 47 crystal oscillators, two frequency doublers using 46's, a pair of 10's in a buffer amplifier and push-pull 211's in the final. Power is furnished by four separate rectifier-filters and the input to the final amplifier usually runs about 500 watts with a plate voltage of 1400. Plate and grid meters are provided for all stages.
The receiver is a duplicate of the original crystal-filter single-signal receiver described in QST in 1932. To its left is a frequency meter-monitor. A 3.5-mc. Zepp antenna, 40 feet high, is operated at all frequencies.
While W2CBD has operated both phone and c. w. in the past, present operation is confined to c.w. in the 3.5, 7, and 14 mc. bands. WAC was made during the last DX contest.
W7BVL, Seattle, Washington
The accompanying photograph is a general view of W7BVL, owned by Howard L. Dull, Seattle, Wash. In the design of the station, good quality transmission rather than power output has been the first consideration. Most of the operating is done on the 20- and 75-meter phone bands, with a power input of 150 watts. W7BVL has been on the air since January 1932.
The rack and panel on the right contains a four stage r.f. unit, consisting of a 59 crystal oscillator, a 59 buffer-doubler which excites two type 10's in push-pull, and a link-coupled 211 as a final amplifier. Grid leak bias is used in the final amplifier, and the coils of the r.f. exciting units are shielded to eliminate feedback. The high-voltage and low-voltage power supplies are at the bottom of the rack; next above are the low-power stages, followed by the final stage and antenna matching network. The antenna used at the present time is a 75-meter center-fed Hertz with 45-foot feeders and 120-foot flat-top.
The audio equipment includes an Amperite velocity microphone with a four-stage resistance coupled pre-amplifier employing a 75 high-gain triode, a 76, and two 37's. The pre-amplifier is not shown in the picture, but it is one completely shielded unit. The output of the pre-amplifier feeds into two 56's in push-pull, followed by two 2A3's as push-pull drivers. These in turn excite four Type 50's in push-pull parallel as Class-AB modulators, making a total of seven stages of audio. The modulator and high-level audio equipment are in the rack on the left - the large meter shown in the picture is in the plate circuit of the modulator, and provides a check on modulation. The additional equipment includes a vacuum-tube voltmeter and a special two-stage amplifier in the phonograph box on the desk. It is utilized for the phonograph pickup, and as an emergency pre-amplifier for a carbon mike.
The receiver at W7BVL is a nine-tube home made superheterodyne which incorporates a.v.c. and an "R" meter. A separate matched impedance doublet receiving antenna is used making possible duplex operation. Cuba, Mexico and the Hawaiian Islands, as well as all districts in the United States and Canada, have been worked on 'phone, and SWL verifications have been received from beyond these limits.
W6GHD, Walnut Creek, California
George S. Bennett of Walnut Creek, Calif., owner of W6GHD, first ventured into amateur radio in 1909. Seven or eight years of sea-going brass pounding followed - must have seemed enough to last a lifetime, since he swore he wouldn't touch a key again! However, the bug wouldn't be downed, and 1932 found him back in the game with more enthusiasm than ever.
W6GHD has two transmitters, the large rack-mounted one at the left in the photograph being a c.w. rig capable of inputs up to a kilowatt. It uses a 47 crystal oscillator, push-push 45's as doublers, a 50-T driver and a pair of 150-T's in the final. An auto-transformer with plenty of taps makes it possible to vary the plate voltage to the final in steps of 500 volts. For trans-Pacific work, a specialty of this station, the input usually is about 600 watts.
The small rig on the file cabinet at the right in the photo is a low-power 160-meter phone job using a pair of 46's to modulate a pair of 45's in the final. The r.f. plate input is about 40 watts. The receiver will be recognized as a Hammarlund Comet Pro.
W6GHD's chief interest is handling traffic over the Pacific. Schedules were maintained with AC2RT and KA1NA for about two years before these stations closed down. At the present time schedules are kept three times a week with both OM1TB and VK6MO, considerable Carnegie traffic being handled with the latter. W6GHD is WAC and also an ORS.
Posted September 16, 2013
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BSEE - KB3UON
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