GATES HF-5

GENERAL DESCRIPTION


5000 Watt 2-22 MC Transmitters

photo Gates HF-5 New and Modern High Frequency Transmitters for 5 kw, available in several models for telephone, telegraph and broadcast service.

These excellent Gates transmitters have already established an enviable reputation in both private and government communications throughout the world. - Designed to operate in world-wide climates and for the rigorous demands of continuous duty. - Available in five models to fit all requirements of voice or broadcast quality, telegraph only, or combinations of modulated and high speed CW service.

Carrier frequency change may be made in a matter of seconds by a combination of continuously variable tuning plus "latch on" tank coil assemblies. - New tube complement means lower tube cost and longer tube life.

Every modern innovation known has been applied to the design of these fine Gates transmitting power plants. Though up to the minute in design, Gates engineers have omitted any mechanical arrangements that are difficult to service, repair or maintain. Gates HF-5 series high frequency transmitters are rugged, heavily built, straightforward designed equipments that will please a world-wide engineering clientele.

5 KW SHORT WAVE TRANSMITTERS

MODELS AVAILABLE for 5 kw service are listed below. Whether the need is for voice quality modulation, broadcast quality, telegraph or combinations of telegraph and telephone, you will find a model exactly as required. Telegraph models will key with perfect square top wave form up to 400 WPM, and excellently up to 600 WPM. Frequency shift keying is adaptable to all models.

TUBE COMPLEMENT Particular note should be made of the 3X2500F3 tubes used in all models in the radio frequency and modulator stages. These low cost, long life tubes mean much in high operating efficiency and low hourly operating cost.

BAND CHANGING is quick and effective. All circuits are continuously variable and tuned from the front panel-with exception of the final tank coil. The Gates "latch on" system allows fast changing of this coil and completely eliminates complicated and costly tuning mechanisms. Four final tank coils are provided to cover the range from 2 to 22 megacycles. Pi-network tuning is also continuously variable.

AUDIO has four stages, with abundance of drive and modulation capacity. Broadcast models employ both modulation transformer and reactor, while voice models are equipped with the new and exclusive Gates designed Hi-cap modulation transformer. This eliminates the modulation reactor-and yet, adds to modulator efficiency at voice frequencies.

POWER SUPPLIES are generous in both size and number. Main supply is full wave, three phase, utilizing either six 8008 or 673 tubes, depending on model selected. Separate supplies are incorporated for low voltage and bias circuits. No combination filament transformers will be found in these transmitters, i.e., no more than one secondary winding to a transformer.

PROTECTIVE DESIGN is very complete. It includes primary circuit breakers in all major circuits and individual supervisory relays in all overload circuits such as RF driver, audio driver, final amplifier, modulator, air failure and exciter failure. Time delay, door interlock and pressure type blower air interlock protective equipment are all standard equipment.

RECYCLING is part of the HF-5 transmitter design. If, for any reason, the carrier should go off the air, the transmitter will automatically turn itself back on four times. Thus, in case of a static discharge, such as across the base of a tower, the transmitter will automatically turn back on.

COOLING is provided by one large squirrel cage blower which sends a torrent of air to the four 3X2500F3 tubes - with excess air blowing into the transmitter proper. A diaphragm air pressure switch protects the tubes against air failure, and even a clogged air filter will activate the diaphragm pressure switch. An additional small blower feeds a small stream of air on the base of each high voltage mercury vapor rectifier tube.

LOADING from the push-pull power amplifier is balanced and will match from 300 to 800 ohm lines. Veeder counter dials on the variable pi-network coils allow accurate logging for frequency change.

5000 WATT TELEPHONE/TELEGRAPH TRANSMITTERS

Construction

All models consist of three cubicles or cabinets which bolt together easily after unpacking. At the bottom of each cubicle are large barrier terminal strips which transfer the wiring from cubicle to cubicle, eliminating any cabling after receiving. Full size front and back doors are provided for the two outside cubicles. Layout design is such that the attendant may walk inside the back-rubber mats are provided. Such refinements as automatic internal lights that turn on when the back door is opened, and utility receptacles for drop cords or soldering iron are standard equipment.

Floor space for the three cubicles or entire transmitter is 125" wide and 49" deep, exclusive of door swing. Broadcast and voice models have external modulation transformer, reactor and power transformer. Telegraph models have the power transformer self-contained in the left cubicle. Heavy cold rolled furniture steel, both resistance and seam welded, with more than ample re-enforcing, is fabricated into the elaborate cabinet section of these Gates transmitting plants. Cabinet is prime coated, then hot sprayed, after which it is hand rubbed. Standard color is gray. All hardware is in chrome, nickel or natural brushed aluminum. Design meets regulations of all countries under the heading of "good engineering practice."

HIGH FREQUENCY TRANSMITTERS, 5 KW

Five Models To Select From

HF-5B, a 5000 watt high frequency broadcast transmitter employing high level modulation, operating from 2-22 mc with uniform audio frequency response within 2 db from 30 to 10,000 cycles. Employs 3X2500F3 tubes as power amplifiers and Class B modulators, providing both better performance and economy in tube cost.

HF-5BX, the same transmitter as the HF-5B, for high frequency international broadcasting but has high speed keyer added so transmitter may be utilized for both high quality telephone and high speed telegraph service.

HF-5C, a telephone type communications transmitter similar in all respects to the HF-5B but with the audio frequency portion designed for communications service only. This allows elimination of the modulation reactor and other alterations in audio frequency components, providing economies where only voice communications will be employed and the wide frequency response and extremely low distortion content of the HF-5B is not necessary.

HF-5CX, an identical transmitter to the HF-5C but with high speed electronic keyer added, providing telephone and telegraph transmission.

HF-5TX, a 5000 watt telegraph transmitter only with high speed electronic keying up to 600 WPM.

TECHNICAL SPECIFICATIONS
Metering Individual meters provided for: Oscillator plate, First Int. Amp. Plate, Second Int. Amp. Grid,
Second Int. Amp. Plate, Third Int. Amp. Grid, Third Int. Amp. Plates (2 meters), Power Amp. Grid,
Power Amp. Plates (2 meters), First Audio Plates, Second Audio Plates, Third Audio Plates (2 meters),
Modulator Plates (2 meters), Filament Volts, Plate Volts. (Telegraph models have audio meters omitted.)
Frequency Range 2-22 mc
Power Output 5000 watts carrier. Note-Under certain circumstances power output above 18 mc will be slightly lower
Output Impedance 300-800 ohms balanced
Frequency Stability 0.005%
Crystal Positions 4 (additional crystal provisions available on special order)
Audio Input 600 ohms; plus 14 dbm
Frequency Response Plus or minus 1.5 db, 30-10,000 cycles broadcast model;
Plus or minus 3 db, 150-4000 cycles communications model
Distortion 3% or less all frequencies between 50 and 7500 cycles for broadcast model;
10% or less between frequencies of 150 and 4000 cycles for communications model
Noise 60 db or better below 100% modulation, broadcast model;
45 db or better below 100% modulation, communications model
Power Consumption at 100% Modulation all models, approximately 19.5 kw, except HF-5TX, approximately 10 kw
Keying Speed 400 WPM with pure square top wave form. Higher practical keying speeds up to 600 WPM easily possible
Size 125" long, 78" high, 49" deep, with door swing front and back doors 40".
Size of largest cubicle 50" wide, 56" deep, 80" high.
Space required for external transformers, where used, 36" wide, 72" long, 36" high
Net Weight telephone models, 9,600 lbs
Gross Weight telephone models, 13,900 lbs
Cubage 317 cu. ft.
Specifications may change without notice

TUBE COMPLEMENT
RF stages AF stages and modulator Rectifiers
Number Type Number Type Number Type
2 3X2500F3 2 3X2500F3 10 8008
2 4-125A 4 845

1 807 2 807

2 6L6 2 6J7



THIS TYPE OF TRANSMITTER IS INSTALLED IN THE FOLLOWING COUNTRIES

ITU Country
ITU Country