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General Notes, a Work in
Progress with Ongoing Additions
6/20/2000
I know from experience that HF and VHF operation does not affect the
two computers in VW Vanagons 1989 - 1991. The 1989 model has some
electrical noise from the electric fuel pump but it is tolerable. I
worked the Russian island, Sak-Halin, just north of Japan twice while
mobile.
Make sure your car is in
very good repair, check the fan belts and general condition of the
engine wiring. It costs $80 to replace the VW alternator bearings at
an auto-electric shop while a new unit from VW Parts is over $250 and
difficult to find. The bearings went out at 70,000 miles.
Replace or clean the
battery terminals.
The exhaust pipe is a
great antenna transmitting noise into your HF radio. While you have
your hands dirty, ground the tip of the exhaust pipe to the frame but
first clean the connecting points down to raw metal then after making
the ground, protect these points with good weather proofing. Most new
cars have ground straps in the corner of the engine hood. Remove the
straps to inspect the ground points, clean and then replace.
Your 100 watt output SSB
rig needs over 20 amps of current at peak output. After a few hours
of transmitting you'll like to start up for the trip home so do
yourself a favor, install a new car battery or add a secondary
battery. You want to be mobile on the highway, not waiting for a tow
truck.
HF Mobile Whip antenna base impedance, RF
Impedance Transformer and Common Mode Current Line Isolator.
translates into WB6ZQZ Triple Ratio Balun.
Engine Noise
My experience follows:
Engine noise is something most of us have to deal with so locate some
braided cable for grounding strap. This is similar to coax shield and
is available in war surplus and very large electrical supply stores.
Mine is double woven and 1" across so it should last for a while and
Radio Shack or marine (boat) supply houses have the terminal ends.
Check out marine supply stores first as they have some very serious
hardware.
For starters, ground the
tail pipe then each corner of the engine hood at the hinge location.
You might check under the hood of a new European car because most of
them have this item. Bypassing the electric fuel pump with .05
capacitors could be more difficult so you should consult your mechanic
or other authorities. All long conductors are great antennas so
bypassing at each end might be helpful.
I've heard that silicon
promotes corrosion from the gases it emits while curing so use
something else to protect connections from corrosion.
Engine computers are out
of my area. You are on your own but there are occasional articles in
QST mentioning individual cars that experience problems. Oh yes, RFI
is not limited to your neighbor's TV set, my 440 FM sigs get into the
XYLs Mercedes up to two blocks away. Well, at least I'll get the
last word in and from a safe distance too .... yea !
Battery Wires, size
and routing
Cell mount and H.F. mount, the toughest part.
Tuner location and wire to antenna base.
Automatic Antenna
Tuner lock-tune control box to prevent the automatic tuner from
initiating a tune when your mobile is being passed by another large
vehicle.
Battery charge indicator. Some add-on 12 volt analog meters draw 2
amps a rate that is not tolerable for permanent connection.
There are now a number of Digital Panel Meters using very low
current LCD digital readouts. These meters can be permanently
wired into the battery system for constant battery monitoring
without fear of power drain.
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