CHA EMCOMM III Portable Engineering and Matching Guide

Matching is not a property of the transformer alone. The installed wire, return current, feed line, ground, and nearby conductors all contribute to what the radio sees.

The CHA EMCOMM III Portable gives a field station more wire and more deployment choices than the smaller EMCOMM II V2 while remaining a one-pound, one-operator system. Its 73 ft radiator, transformer, line winder, and suspension hardware are designed to move from a backpack to an operating site in under 15 minutes.

What matters for this decision

• A single 25 ft non-resonant counterpoise is the documented all-band starting point; four can be a practical efficiency compromise. The guide also provides shorter band-based alternatives. Keep the connection method consistent with the actual counterpoise hardware.
• Begin with the current guide’s dimensions and connection point.
• Measure broadly at low power, then change only one conductor length, tuner state, or routing variable.
• A low station-end SWR does not by itself prove high radiation efficiency or controlled common-mode current.

Why operators choose this system

The operator can choose a sloping wire or inverted-L when there is time to use one or two supports, an end-fed inverted-V when one center support and a faster layout make more sense, or a horizontal NVIS arrangement when regional coverage is the priority.

Published operating reference

• Published continuous frequency range: 1.8–55 MHz.
• Published power: 50 W continuous duty and 100 W intermittent duty.
• Published wire length and weight: 73 ft and approximately 1 lb.
• Published setup: one trained operator in less than 15 minutes.

Make the next deployment repeatable

Record product revision, configuration, wire dimensions and bearings, endpoint heights, support hardware, return path, coax and choke condition, tuner state, analyzer reference plane, weather, and on-air reports.