Metro Amateur Radio Club

MARINE GO KIT by Greg W9WIZ

Most “go kits” are designed portable enough for self-sustained operation on the amateur bands at on-scene locations. They have provisions for external antennas and portable power supplies. My “go kit” has a different purpose.

My “go kit” is designed around a VHF marine radio. I am a volunteer staff communications officer with the Coast Guard Auxiliary in the Chicago area. My “go kit” has a two-fold purpose: be a self-contained portable radio (instantly useable for radio checks when carried from boat to boat) and be sustainable enough to be used as a base of operations (a radio facility used in a Coast Guard Auxiliary exercise.)

For portability, my kit is designed to fit into a small plastic tool box. See picture.  I mounted the radio to the bottom of the tool box using a mobile bracket. For instant usability, radio power is selected between an internal 7ah battery and an external cigarette lighter power cord (in order to be able to use boat/car power) stored on the underside of the lid.

For charging the internal battery, there is an on/off switch to connect/disconnect an external “wall wart” charger to the internal battery. Because the charger (which physically rests on the internal battery) is hard-wired into the kit, I installed the charger switch so as to prevent the windings of the charger from discharging the internal “go kit” battery when the internal battery option is selected.

The marine radio can operate at 1 watt for boat radio checks and 25 watts for base operations on Coast Guard Auxiliary exercises. Because the radio can operate at 25 watts for an extended period of time and the tool box construction does not offer a lot of ventilation, I installed a small switched fan (CPU fan) aimed at the radio’s heat sink.

(Tech note: The main fuse is wired in the circuit after the power selector switch, so that the radio is fused no matter which power source is selected. The power selector, charger and fan switches have “on” indicator lights. A jack is provided for headphones/external speakers. Extra fuses are carried in a closed compartment. All switches and connectors are functionally labeled so any (CG certified) operator can operate comfortably.)

There is an extendable portable antenna, carried in the kit lid, which can be attached to the antenna connection. An external antenna can be connected via cable to the same antenna connection.

Perhaps the most fun feature to design into this kit is the inclusion of a small VTVM wired directly to the internal battery, activated by a SPST push button switch, to check battery condition.

This “go kit” is recognized as a Coast Guard Auxiliary Facility and the call sign (NM9TG) remains with the radio, regardless of the (CG certified) operator.

I had fun building this “go kit.” I utilized my experience with amateur radio for the fundamentals and adjusted some of the construction parameters for marine usage. The basic design

can be used for a “mobile“ amateur radio, VHF, UHF or HF.

. photos by K9KDE