Hammarlund Mfg. Co., New York / Mars Hill NC

HQ - 140 X

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überarbeitet am 14.11.2010

The HQ-140X is a shortwave multiband receiver with bandspread dials for the amateur radio bands. It makes part of the early series of the Hammarlund shortwave receivers like the HQ-129X and the HQ-150X.

Single conversion superhet, I.F. 455 kHz

Analog dial, calibrated bandspread dial for the ham bands

AM, CW with BFO



RF gain, band spread dial, crystal phasing / notch filter

The tabletop radio is usually wired to be powered from 115 V mains, the standard mains voltage in the U.S.A. Just make sure about the correct voltage before You change the plug and connect the receiver to the mains outlet.
The receiver's dimensions are 51 x 43,3 X 28 cm, a hinged lid gives access to the chassis for tube replacement.

In the middle of the frontpanel, You find the two square dial windows, the round main and bandspread frequency dials are rotated behind the fixed pointer line. The round signal strength meter and the antenna trimmer are located in between.
The huge tuning knobs for the main tuning and the bandspread dials are located below the corresponding dial windows, the bandswitch between them selects from the following band segments: 540 - 1320 kHz, 1,32 - 3,2 / 3,2 - 5,7 / 5,7 - 10 / 10 - 18 / 18 - 31 MHz. The bandspread dial should be set to "100" for a correct reading in the main tuning dial, for use of the bandspread dials, the main tuning dial should be set to the upper edge of the corresponding amateur radio band, so that the readings from the bandspread dial should give correct results.

On the left side of the front panel, You find the rotary controls SENSITIVITY, corresponding to the R.F. gain control which should be set to maximum for normal operation, and the two controls of the crystal filter, the bandwidth selector and the phasing control to eliminate an interfering signal.
On the right side of the front panel, You find from the top the BFO control for the reception of CW and SSB signals, the modes witch with the positions MAN (AM, manual i.f. gain control), AVC (AM, automatic gain control) and BFO. The AUDIO GAIN control acts as volume control and is combined with the main power switch.

For reception of an AM signal under standard conditions, the STANDBY switch should be set to RECEIVE, the SENSITIVITY control should be set to maximum fully clockwise, the mode switch to AVC. For normal reception, the crystal filter can remain turned OFF. The receiver is switched on with the AUDIO GAIN control, after a while (it takes a while until the tubes are glowing), You hear a slight hiss in the headphones.
Radio "Deutsche Welle" can be found in the 49 m broadcast band in the lower frequency part of the 5,7 - 10 MHz shortwave range. The bandspread dial should be set to "100", so the main tuning dial readings are more or less accurate, then look out for the signal of the transmitter on 6075 kHz somewhere below the 6.1 MHz dial mark. When You have identified the station, You can use the antenna tuner to tweak for maximum reading on the signal strength meter.

The antenna signal is fed via a tuned antenna circuit and a R.F. amplifier stage (V2: 6BA6) to the mixer(V3: 6BE6), with the oscillator signal (V1: 6C4), the standard intermediate frequency of 455 kHz is generated. After two I.F. amplifier stages (V4-6: 6BA6), the crystal filter is switched in between them, the signal is fed to the demodulator stages.
One diode system of V7 (6AL5) is acting as AM detector, the second system is used for the noise limiter. For the reception of CW signals, the signal of the beat frequency oscillator (one system of V8 (12AU7)) is added. The second triode system of the 12AU7 is used as A.F. preamplifier, V9 (6V6GT/G) in the final A.F. amplifier stage.
The rectifier V11 (5U4G) and the voltage stabiliser V10 (0C3/VR105) are both used in the power supply section of the receiver.

The Hammarlund HQ-140X is a well constructed general coverage and ham band receiver, it's single conversion design is typical for the circuitry found in hollow state receivers from the early fifties. The receiver with it's "boatanchor" weight can still be used as a reliable mediumwave and amateur band radio, as long as You can do without high precision dial calibration or digital frequency readout.

© Martin Bösch 26.3.2009 / transl. 14.11.2010

weitere Lektüre:
d/e: HQ-140X in www.radiomuseum.org
e: Osterman, F.: Shortwave Receivers - Past and Present