13
Vehicle Installation
Our experience is that the antenna can function well in several locations on a vehicle.
The length of the ground strap should be kept to less than three feet long (from a screw
on the mounting bracket to the vehicle body/frame). Sometimes it's a good idea to test
the location first.
The ground strap should first be connected to the sheet metal of the vehicle. If the SWR
on 20 meters or 15 meters is above 2:1, another strap to the frame may also be
necessary.
Use at least 15 feet of coax. Short runs of coax can affect the SWR reading at the
transceiver.
Long supports below the antenna can cause matching problems. If you must use a long
support, try grounding it first. If the antenna will not tune on one or two bands, try
isolating the support from ground.
Ladders on recreational vehicles are also problematic. While many have had very
successful installation on ladders, others have had difficulty. Some have found that
running a ground strap from the mounting bracket to the metal framing of the RV is all
that is needed. Others have had to run one or two radials on the top of the RV. Some
have found that metal trim and luggage racks are all that is needed. In other words,
some experimenting is necessary for installation on an RV.
If you pull a trailer and plan to mount the antenna on the towing vehicle, make sure
there is a good RF connection between the towing vehicle and the trailer. If this is not
done, you may soon discover your antenna system has an intermittent connection. The
problem is caused by loose (intermittent) coupling between the vehicles through the
trailer hitch. A simple jumper cable across the hitch
corrects the problem.
The mag mount shown in the picture below will
work.
The ‘T’ type of mag mount that has
aluminum strips between the magnets will not
work.
With the ‘T’ type of mount of there is a real
poor connection to the shield of the coax. In
addition, there is very little coupling to the vehicle.
