photo Gates HF1 Three models of 1000 watt (carrier) transmitters are offered to those who desire the very finest in short wave equipment. A model for short wave broadcasting, a second model for voice and telegraph communications and a third model for telegraph only. The several folIowing pages fully describe these quality filled radio transmitters.

1000 Watt Telephone and Telegraph Transmitters

In the field of heavily built, continuous service, commercially built 1000 watt high frequency transmitters, there is nothing that will equal the new line of Gates HF1 transmitters. - Large in size to hold large components that will operate 24 hours daily, year-in and year-out. - Complete in equipment complement to assure nothing left wanting in handling tough schedules-and modern right up to the last minute with advanced engineering.

Operation is continuously variable from the front panel, other than the final tank circuit which employs plug-in coils. Frequency change may be made within seconds. Four radio frequency stages, four audio stages and four power supplies, along with rugged circuit protection in the most complete relay system ever used in a 1000 watt equipment, add to the reliability expected in commercial equipment.

There are 13 meters in all, ten of which are 4 inches. Full size front doors prevent brushing against exposed controls. Ventilation is by means of a large squirrel cage blower with filtered air intake. Entirely new, clean, fresh air is sent to every part of the transmitter each 15 seconds. - Engineers who follow a plan of carefully selecting transmitting equipment on the basis of reliable performance and more operating features will, indeed, want to seriously consider the Gates HF1 series.

For Communications or Broadcast Service

There is no substitute for rugged and heavy design where around-the-clock press copy or important voice and telegraph communications are concerned. This is certainly true, also, in eighteen to twenty-hour daily short wave broad casting.-The Gates HF1 series 1000 watt transmitters will fill these requirements anywhere in the world.

CONSTRUCTION - HF1 transmitters are built into a large and roomy enclosure, having double front and back doors. Directly in the center of this cabinet, or enclosure, is a large squirrel cage blower that changes the air four times each minute. This air blast not only maintains low inner-cabinet temperature, but prevents dust from settling. The air intake is filtered. Cabinet is of 16 gg. and 11 gg. cold rolled steel, resistance and seam welded. It is then zinc chromate primed, after which it is hot sprayed in medium gray and hand rubbed. All hardware is in chrome, nickel and brushed aluminum. Size 72" wide, 33" deep and 78" high, exclusive of door swing.

METERING - Thirteen in all. Ten large 4" meters along the top of the cabinet read not only all necessary voltages and currents, but the additional circuits that make tuning and maintenance easy. Three smaller meters are in the oscillator driver circuit.

PROTECTIVE RELAYS - It is believed that the HF1 transmitters have a more complete relay system than any similar equipment in the 1 kw power range. This complement of relays includes primary circuit breakers, filament and plate contactors, dash pot time delay relay and individual overload relays for RF driver, power amplifier, modulator and audio driver. These relays also activate when rear doors open to expose high voltage.

HF1 Series 1000 Watt Transmitters

RADIO FREQUENCY DESIGN - The RF portion of the HF1 transmitter has, as the input source, four crystals of either the temperature or non-temperature controlled type. These may be selected from the front panel into the 6AG7 oscillator which excites a 2E26 first amplifier. - The output of the 2E26 tube feeds to push-pull 4-65 tubes, which do not require neutralizing, and supplies an abundance of drive at all frequencies for the push-pull 450TH final power amplifier tubes. Neutralizing of the power amplifier is fixed at all frequencies. RF output is balanced through a pi-network, matching a 300/800 ohm line. Modulation monitor pickup coil is provided.

AUDIO DESIGN - Four push-pull audio stages provide an excess of modulator power for both voice and broadcast models. Voice model uses Hi-cap modulation transformer, emphasizing voice frequencies, while the broadcast model uses linear standard modulation transformer and reactor combined for wide frequency response. Tube complement, all push-pull, is 6J7 first audio, 6J5 second audio, 845 third audio and 450th modulators.

BAND CHANGE - Operation is continuously variable at all frequencies, and in all radio frequency stages except the final power amplifier, for which five sets of plug-in coils are provided-which may be changed instantly. Turret coils, selectable from the front panel, are generously used throughout.

KEYING - The standard transmitter as supplied is for 60 WPM keying; however, it can be supplied for keying up to 400 WPM and for frequency shift keying, as well. Keying is clean and free from chirps or thumps.

POWER SUPPLIES - Five power supplies divide the work load requirements and deliver added reliability. These are: high voltage, intermediate high voltage, low voltage RF, low voltage AF and bias (telephone models only). Primary is 230 volts, 3 wire, single phase, 50 or 60 cycles.

For Voice, TeIegraph or Broadcast

Three Models To Choose From

HF1-2Y high fidelity broadcast transmitter with full audio frequency response from 30 to 12,000 cycles. Low distortion and noise level make this one of the finest in medium power short wave equipments. Operates from zero level input and is complete, ready to attach to transmission line and studio equipment.

HF1-3Y voice quality telephone and telegraph transmitter. This model is identical to the HF1-2Y, other than the audio section. It is designed for best operation between 150 and 3500 cycles-other frequencies have been attenuated. This model may he purchased with frequency shift keyer or with 400 WPM keyer. Supplied standard, it keys at 60 WPM. It may be used with the Gates tubeless modulation monitor.

HF1-XY telegraph transmitter only. This model is also the same as the above models HF1-2Y and HF1-3Y, but has the audio portion removed. It is so built that the audio portion may be added at any later date to complete a telephone or broadcast model. May be purchased with frequency shift keyer, or 400 WPM keyer, if desired. Standard model keys to 60 WPM. When used with properly designed Rhombic antenna, remarkable areas may be covered.

WHAT IS SUPPLIED - Each transmitter is supplied with one complete set of tubes, duplicate instruction books and all necessary materials to make it operative-except the crystals (two different types are offered). Speech input equipment to go with the broadcast and voice models will be found listed elsewhere; as will antennas, microphones, telegraph keys, frequency shift keyers and anything required for the complete radio station. Transmitters are boxed in solid wood boxes, carefully prepared for either domestic or overseas shipment, as ordered.

Frequency Range 2-22 mc
Carrier Stability 0.02% with JI-H17 crystal or 0.005% with JKO-2 oven
Number of Crystals 4, with two each socket or two per oven as ordered
Power Output All models 1000 watts CCS (slightly greater or intermittent duty)
Power Input At 230 volts, 3 wire, single phase, for HF1-2Y or HF1-3Y at average modulation, 4400 watts.
HF1-XY telegraph model, 3550 watts
Output Impedance 300 to 800 ohms balanced
Modulation Monitor Coil Impedance 70 ohms
Frequency Response HF1-2Y 30-12,000 cycles ±1.5 db
HF1-3Y 100-3500 cycles ±2 db
Distortion 3% or less 100-7500 cycles for HF1-2Y
10% or less 100-3500 cycles for HF1-3Y
Noise 60 db below 100% modulation-Model HF1-2Y
48 db below 100% modulation-Model HF1-3Y
Audio Input 0 db at 600 ohms
Keying 60 WPM as standard. Electronic keyer available for 400 WPM at slightly added cost.
Also adaption for FSK at no additional cost where stated
Size 78" high, 72" wide, 33" deep. Door swing, front and back, 26"
Shipping Weight 3100 lbs. domestic or export. Cubage 255
Specifications may change without notice

RF stages AF stages and modulator Rectifiers
Number Type Number Type Number Type
2 450TH 2 450TH 2 575A
2 4-65A 2 845 2 872A
1 2E26 2 6J5 1 5U4G
1 6AG7 2 6J7

2 5U4G 2 5U4G


ITU Country
ITU Country