Note
HM-2140 1979-1983 $74.95
HM-2140A 1983-1991 $99.95
This handy little kit was the last of a series of HF power/SWR meters that began with the AM-2 in 1957. It remained on the market right to the end. The HM-2140 provides simultaneous indication of both forward and reflected power by means of two separate meters, and will read PEP or average power. In addition, the instrument contains an SWR bridge. It has a usable frequency range from 1.8 to 30 MHz and will handle forward power up to 2000 watts and reflected power up to 500 watts. Front panel push buttons select power ranges (0-200 watts and 0-2000 watts), PEP/average, SWR set/forward/reflected, and battery test, while a control combines SWR sensitivity and on/off function.
The removable sensor unit is factory assembled and calibrated and can be mounted up to 6 feet away from the readout box. The HD-2140 requires a 9 volt battery, and a jack is provided for use with a power cube.
To check the battery, rotate the SENSITIVITY control fully counterclockwise until it clicks and press the PEP/AVG switch.
The only differences between the HM-2140 and the HM-2140A are the color of the cabinet and the style of the knob. The HM-2140 is two-tone SB green. The “A” version is brown to match the rest of the “little brown box” series. Heath also took the opportunity to raise the price by $25.
Note: Best results are obtained with readings that are greater than the mid-range of the meter. Although it is possible to use the meter with low-power transmitters, best results will be with power levels of 25 watts or greater, since accuracy is specified as a percentage of full scale.
Note: Load impedance is not specified, but calibration is done with a 50Ω dummy load. Operation with other impedances will produce unreliable readings.
Just a few months after its release in 1979, Heath announced a VHF version—the HM-2141. The HM-2140 and the HM-2141 are indistinguishable at a distance.
References:
Review. QST. Feb 1980 p. 40.
Comparisons. QST. Feb 1991, p. 35.
Frequency range: 1.8 to 30 MHz
Functions: forward and reflected power (average and PEP), and SWR
Meter ranges:
forward (2 scales): Low, 0 to 200 watts; high, 0 to 2000 watts
reverse: (3 scales): low, 0 to 50 watts,; high, 0 to 500 watts; SWR, to 3:1
Insertion SWR: less than 1.05:1
Accuracy (full scale):
200 and 2000 watts (forward), 500 (reverse): ±5% (average)
50 watts (reverse): ±7.5 (average)
Power requirements: one 9-volt battery (NEDA 1604), or power cube
Photos, general information and specifications from "Heathkit: A Guide to the Amateur Radio Products," by Chuck Penson, WA7ZZE. Used with permission.
