Production year 1961 - 1964 at $69.95
The Hallicrafters S-120 is a single conversion, superheterodyne, general coverage receiver that is used for the reception of AM and CW signals. The S-120 turned out to be a very popular receiver for the Hallicrafters company and was the successor to their famous S-38 line. The receiver incorporates four tubes and a selenium rectifier in its circuit. The S-120 has a total of four bands with continuous coverage from 540 KHz to 31 MHz. The first band covers 540 KC to 1600 KC, the second band covers from 1.6 MHz to 4.4 MHz, the third band covers from 4.4 MHz to 11.5 MHz, and the fourth band covers from 10 MHz all the way up to 31 MHz. The analog slide-rule frequency display has been imprinted with a guide to the frequency settings for foreign, WWV, government, aviation, and other exotic stations.
The standard broadcast band has been marked in two places with a Civil Defense emblem which consists of a triangle inside of a circle. This CD emblem is found at 640 KHz and 1240 KHz. The operator was instructed to tune to one of these two frequencies for official news, instructions and information in the event of a civil defense emergency. The triangle emphasized the 3 step Civil Defense philosophy that was used before the foundation of FEMA and Comprehensive Emergency Management. When this receiver was manufactured, the Civil defense was an effort to prepare civilians for military attack. Civil defense uses the principles of emergency operations: prevention, mitigation, preparation, response, or emergency evacuation, and recovery. Programs of this sort were initially discussed at least as early as the 1920's but only became widespread after the threat of nuclear weapons was realized. Since the end of the Cold War, the focus of civil defense has largely shifted away from military attack to national and local emergencies and disasters. The new concept is described by a number of terms, each of which has its own specific shade of meaning, such as crisis management, emergency management, emergency preparedness, contingency planning, emergency services, and civil protection.
The S-120 comes equipped with an internal speaker which is of the permanent magnet moving coil design that measures five inches across and has a voice coil impedance of 8 ohms. Received signals exit through a perforated section on the left side of the unit. If headphones are to be used, the receiver requires a set with an impedance of between 50 to 10,000 ohms. The S-120 employs a three-way antenna system for maximum flexibility. It has a built in ferrite rod antenna for the broadcast band, a 45 inch telescoping whip antenna, and connections located at the rear for an external antenna.
The Hallicrafters S-120 also features band spread tuning. The band spread dial has been calibrated from 0 to 100. To operate the band spread dial, set the main tuning dial to the high frequency limit of the range of frequencies to be covered and then tune stations in with the band spread control. For example: say that the 40 meter amateur band is to be covered. Set the main tuning dial pointer to 7.3 MHz and tune in the stations with the band spread control. The band spread control allows for fine tuning of stations and forces the operator to move across the frequency spectrum at a much slower pace, thus helping to insure that weak stations are not missed. Tuning the bandspread control from 0 to 100 tunes the receiver progressively higher in frequency. One thing to keep in mind is that the calibration of the main tuning dial will only be correct when the band spread dial is set to 100.
The operator controls of the S-120 consume the entire bottom portion of the front panel. Scanning across the front from left to right, the controls and their functions are as follows: Bandspread tuning control knob, On/Off and Volume control knob, a 1/4 Headphone jack which automatically disconnects the internal speaker when used. Located in the center of the S-120 is a control knob to turn On and Off the Beat Frequency Oscillator(BFO). The BFO is used primarily to provide the necessary beat frequency tone when receiving CW. In addition to this however, this control also acts as a sensitivity adjustment which aids in the reception of extremely weak signals. Next we run into the only switch that is found on the S-120. This switch is labeled Receive on the top and Standby on the bottom. This Receive/Standby switch removes the plate voltage from the tubes of the S-120 which makes the receiver inoperative during times of transmission. This switch can also be used to conserve power during a standby period when it would be important to have the radio spring to life with just a flick of a switch instead of having to wait for the tubes to warm up. Next is the four position Band Selector knob that is used to select one of the four bands for reception. The last knob on the right is the Main Tuning control knob.
The 4 tubes that are used in this receiver along with their functions are as follows: 12BE6 = Oscillator & Mixer, 12BA6 = IF Amplifier and BFO, 12AV6 = 1st Audio Amplifier, AVC and Detector, and a 50C5 as the Power Output Amplifier. The radio has two #47 dial lamps and is housed in a three sided sturdy metal cabinet. The Intermediate Frequency(IF) of this receiver is the standard 455 KHz. The power source requirements are 105 to 125 volts DC or between the same voltage range but with 60 cycles AC. It is also possible to operate the receiver from a 210 to 250 volt AC or DC power source by using a special line cord adapter with the Hallicrafters accessory part number of 087-201566. The normal power consumption of the S-120 is 30 watts. The physical dimensions of this receiver is 13 1/2 inches wide by 5 7/8 inches high by 8 3/4 inches deep and it weighs in at 10 1/4 pounds.
The photograph on the right is of the back of the Hallicrafters S-120. The back panel is not in place and is missing on this receiver. There is only two connections that are found on the rear apron as follows, at the left is a two terminal external antenna connection, and at the right is the power cord. The paper sticker to the left of the power cord lists the serial number of this receiver. The orange wire from the ferrite rod antenna does not make any electrical contact with the external antenna screw connection on the rear apron. I have added to the antenna terminal screw as a means to help hold the ferrite rod antenna in place since the back panel is missing.
The rear cover of the S-120 is labeled above the 2 terminal antenna strip with "GND" for the left terminal, and "ANT" on the right terminal. This is an abbreviation for "Ground" and "Antenna". The supplied 45 inch telescoping whip antenna should be connected to the "ANT" terminal. A ground wire should be connected between terminal "GND" and an earth ground for single wire antenna systems. A doublet antenna system with a balanced transmission line will have one side connected to terminal "ANT" and the other side of the transmission line connected to the "GND" terminal. If a concentric transmission line(coaxial cable) with a grounded outer conductor is to be used, connect the inner conductor to terminal "ANT" and the outer conductor to "GND". The station ground connection should be connected to the "GND" terminal.
The Hallicrafters models SW-500, WR-600 and WR-1000 are electrically the same radio but have a different color cabinet, dial bezel, and knobs.