Information for Proper Operation of High Powered 10 Meter Amateur Radios

(From Galaxy)


The  high powered 10-Meter Amateur Radios are capable of transmitting 100-200 watts plus to the antenna system. This requires a more robust antenna and electrical system than what might be used for the more common low powered or CB radio systems.

The electrical system must be capable of delivering a constant 40 amps minimum of DC current at 13.8 volts. These radios must be wired with both red (positive) and blue (negative) wires direct to the battery with 8ga for up to 10 feet and 6ga. for over 10 feet of cable to the battery. Attaching the negative lead to vehicle chassis ground will not work. When connecting a high power 10 meter radio to a DC power supply the power supply must be rated at a minimum of 40 amps constant at 13.8 volts DC.  

Some radio antennas that may have worked with lower powered models do not always mean they will work with high powered radios. High powered radios tend to stress and expose any weak spots in the antenna system such as inadequate antenna grounds, cheap coax and poorly soldered coax connections. Magnet mount type antennas are never a good choice for high powered radios. Newer model Class 8 trucks with fiberglass cabs will not normally have good grounds supplied to the mirror mounts and may need to be retrofitted.

Approximately 65% of today’s class 8 trucks are outfitted with a “multiband” antenna of some type. The antenna is outfitted with “Traps” to provide the proper wavelength for your cell phone, AM/FM radio and CB radio. These antenna systems will not work with high powered radios. If you have a vehicle with dual antennas but only see one coax at the connector on the rear of your radio then it’s very likely you have some type of splitter box between your radio and the antennas. Also if you do not see a separate AM/FM antenna it is most likely you have a splitter box. With a case such as this you must install a separate high quality length of coax from the high powered radio directly to the antenna or a special co-phased coax harness if running dual antennas.

Today’s new high powered mosfet radios are not as tolerant to a poorly matched antenna system as the older low powered models were. This means extra special attention must be paid to making sure your antenna system is properly matched to your vehicle. Antennas should always be tested by technicians trained in antenna impedance and VSWR. The SWR meter, which comes built-in with some of the more expensive models, is not a precision piece of test equipment and should not be trusted as completely accurate.

Grounding cannot be over stressed. With RF communications it is the #1 culprit of the radio world. Poor grounds cause problems to antenna systems and radio operation. Approximately nine times out of ten, if you have a problem with your radio setup the cause will be poor grounding. Knowing this you’ll also understand that as the RF power of your radio increases so does the chance of exposing some type of grounding problem. As a general rule of thumb: try to keep all grounds as clean as possible and all ground straps as short as possible. Always try to add a short ground strap from one of the radio cover screws to your vehicle chassis ground.


(Additional information from GI Joe's)


Hooking up Cb radios, 10 meter radios or amplifiers over 50w:


In a 18 wheeler the red and black dash terminals will usually run up to 300w MAX (18amps) although It is not recommended. The dash terminals are usually rated at 15 amps, a few are 30 amps. Cigarette hook ups are usually rated at 15 amps in a 18 wheeler. I would not recommend running over 200w MAX from them.

For Freightliners and other trucks with the 2 hook up wires in the overhead (usually 2 yellow wires or 1 white and 1 green) these connections will not usually not run over 100w MAX. You may need to hook to the large wire in your dash that comes up from the battery. If you are not getting enough power to the unit it may dim when you talk, flicker, flutter, distort or squeal.

The best way to hook up Cb radio, amplifier or 10 meter radio units over 200w is to run the HOT & GROUND from the unit directly to the battery HOT & GROUND post. This gets more power to the unit than grounding to the frame.

10ga wire will carry up to 575w MAX audio power. 8ga wire will run 600-1200w MAX audio power. For long runs over 15’ at 500w+ the 6-8ga would be best. The longer the cable run the larger it should be. It does not hurt to go a little larger as the Galaxy information above states.

In a car or pick-up your wiring and cigarette hook up is usually only rated at around 6 amps. For over 50w you should run power directly to the battery HOT & GROUND post.

Always put an in-line fuse on the wire at the HOT battery post. This will prevent the hot wire from catching fire if it ever grounds out to the frame.

Fuse size: Use 10 amps for every 100w of power. Ex. A 200w unit would need a 20amp fuse.

We sell radio/amplifier Hook-Up Kits on our website with everything you will need (see website left menu). State in the comment box on the on-line order form what unit and/or what wattage you are hooking up so we can include the proper fuse and fuse holders.