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E-644: Hallicrafters SX-62

E-644, All Wave Receiver SX-62; developed and produced by Hallicrafters Co., Chicago IL.

Hallicrafters presented their SX-62 as a successor of their all-wave receiver SX-42, which carried the military designation E-614 in the year 1948. Technically the set is quite similar, but it features a linear frequency and comes without a signal strength meter.

In addition to the shortwave bands, the receiver also covers the VHF range used for military communications; the exact role of the receiver is not known.

(c) Image by Courtesy of Lennart Nilsson
© Image by Courtesy of Lennart Nilsson

Technical Data

Power Supply

Dimensions

  • 508 x 260 x 406 mm, 29 kg

Accessories


Operation

The main difference between the SX-62 and the SX-42 (E-614) is the wide linear frequency dial, the dial pointer can be moved by rotating a button at the left of the dial to set ist to the calibration markers. Most of the controls are arranged in one row, on the left, the band selector ist located, followed by three switches for standby / receive operation, crystal calibrator and noise limiter, next is the main tuning knob.

The five controls to the right are the volume volume control, which also acts as mains switch, and the reception mode switch to select FM, AM and CW operation, in the last position the BFO is activated. This is followed by the selectivity switch to select the bandwidth, the tone control, and finally the sensitivity control, which controls the radio frequency / RF gain and which is used to prevent overloading.

On the main dial, the band, which comes with the highest number of station names, is the shortwave band - most international stations are mentionned (and not, as we are used from Europeam sets, the medium wave band); on the main dial, the active range is backlit.

Technical Principle

After two RF preamplifier stages (6AG5), the signal is fed to the mixer (7F8), in the low frequency bands 1 - 4 resp. on frequencies below 30 MHz, it is converted to the standard IF of 455 kHz, in the higher frequency bands 5 and 6 resp. 27 - 109 MHz to the higher IF of 10.7 MHz. After three IF amplifier stages (6SK7, 6SG7, 7H7), in AM mode it is demodulated. In FM mode, V8 acts as limiter and demodulation is done in the discriminator stage (6H6). After a AF preamplifier stage, two 6V6GTs act as power amplifiers and give excellent performance with 8 watts of output power. In the shortwave bands, a crystal calibrator, a noise limiter and a BFO for CW and SSB reception can be activated.

Valve setup

V1 (6AG5, 1st RF preamplifier); V2 (6AG5, 2nd RF preamplifier); V3 (7F8, mixer stage); V4 (6C4, oscillator, crystal calibrator); V5 (6SK7, 1st IF stage); V6 (6SG7, 2nd IF stage); V7 (7H7, 3rd IF stage); V8 (7H7, FM: 4th IF stage, AM: demodulator, AVC); V9 (6H6, discriminator), V10 (6SL7GT, AF preamplifier); V11, V12 (two 6V6GT, AF output stage); V13 (7A4, BFO); V14 (6H6, noise limiter). Gl (5U4G, mains rectifier), stabilizer 0D3 / VR-150 .

Development

Field use

According to Swiss Army documents, to the Hallicrafters SX-62 the military designations E-605 and E-644 habe been assigned.

Manuals

Additional information

en/e-644.txt · Zuletzt geändert: 2022/09/16 20:19 von 127.0.0.1