Really weird thing, when I key the mic on the radio the engine just shuts down. I thought it might be a bad radio but I swapped it out for another and same thing. Ive got a dual battery kit and everything is fused and grounded properly.
I there any way this has to do with the antenna? I’ve probably got 20 VHF radio’s on the farm and Ive never seen this before but having said that, I also know very little about them and could totally be installing them wrong all along. Need some help.
Short answer:
Assuming everything is OK electrically, it could be RF, radio frequency, interference wrecking havoc with the engine electronics. I have a base station system that can fire off all of my smoke detectors at home if I push too much power through my vertical antenna. So if you turn down the power can you transmit and still keep your rig running? Are you use good quality coax with a good shield routed away from the engine electronics? A good Ham could look at your setup and offer advice.
Long answer which can be ignored:
1) Poor SWR, standing wave ratio. This can happen for a number of reasons. Basically a good antenna installation will have an SWR of < 3, most of the current sent to the antenna is radiated outward and is not "reflected back" to the radio. For example, if the antenna is not mounted well above the roll bar, the SWR will be elevated. Or if you are using a mag mount antenna that requires a large metal ground plane and instead mount it on a plastic roof, the SWR will be high. The list of causes of high SWR is almost endless. If you know a knowledgable ham with an SWR meter, they can actually graphically view the SWR from the antenna over various "channels."
2) Common Mode Current: If you are using a 1/2 wave antenna then the coax is acting as a component of the antenna and there can be current traveling down the _outside_ surface of the coax back to the radio. As a Ham Radio operator with a second floor shack with an end fed antenna I have actually receive an electrical "bite" when touching the chassis of a radio due to such common mode currents. Grounding the antenna to a metal chassis can provide a route for the current away from the radio. "Choking" the current _near_ the antenna feed point can help. A simple UHF VHF choke is to wind some coax in a loop 5Xs into about a 4 inch loop.
3) Using a dummy load: A ham friend may have a simple dummy load which is used in place of the antenna for a test. Dummy loads basically absorb all of the rf energy and converts it to heat. They often produce an SWR of nearly one. So if your system works fine with a dummy load the problem is unlikely to be the radio or related to the electrical system.
