I have fielded many questions on how to install modern day mobile HF rigs into todays vehicles.

With everything being molded plastic mounting and grounding the equipment can be an issue. The photos attached are that of installing a Yaesu FT-100D w/ATAS-100 antenna. Since then, I have swapped in an updated FT-857 and ATAS-120 into the same mounting positions. The only issues I have run into are grounding to prevent EMI/RFI to the vehicle electronics and stray RF due to coaxial radiation.

The first can be prevented by bonding the radio chassis to the vehicle chassis. This is easier said than done within these newer vehicles. Ground bonding can only happen with high quality straps or cables connected directly to the transmitter and vehicle chassis. At points where the strap/cable is connected, all impurities need to be removed. This means the removal of paint, primer and chemical coatings (Alodine). You are looking to achieve a connection that measures less than 1 milliohm. That restated is less than one thousandth of a ohm (1/1000). This isn't something you can accurately measure with a standard ohm meter. And unless you can get your hands on a micro-ohm meter, you are shooting in the dark!

What I have found in practical experience is that if your surfaces are properly prepared, you will have connection points that fall into the .00030 Ohm area or less. A technique I have learned is checking your prepared surface with a tiny amount of water. If the water beads up, you still have surface contamination that requires removal. If you achieve a water break free surface, you are ready to attach your connection.

I recommend you retreat the surrounding area afterwards to prevent any oxidation of the surfaces. This approach used on your equipment grounding will help prevent many little issues later on during the it's usage. One last thought.... Always remember this when it comes to grounding.... No matter what your final ground connection reading is, it will always increase in value from the time forth. This means your grounds will eventually become bad.

The second issue I ran into was on 28MHz (10 Meter Band). When transmitting, I found that the coax shield was radiating in the vehicle. This presented the symptoms of having random SWR (antenna tuning) problems. This issue was addressed by creating an RF choke by wrapping the coax around a ferrite core 4 times. This gave just enough inductance to prevent the RF from traveling down the coax.

Though this isn't the installers guide to vehicle installations as everyone will be unique. I'm hoping that this will give you some thoughts on how to approach yours.