[aprssig] RE: D700 Honda Odyssey Mounting Options

Dave Baxter dave at emv.co.uk
Tue Nov 15 11:04:56 CST 2005

Hi Jim...

>From personal experience, so long as the ground is "good", ie low
impedance, and you do not have any odd voltages between grounds, you
shouldn't have any trouble.  If you have odd voltages between different
parts of the car, Hmmm..  Something is not right.  Either a fixing has
corroded, a ground lead fallen off, or even a corroded fixing is acting
as a battery!  Steel and Aluminium being suprisingly effective when wet!

Each "accessory" (radio) I have has it's own 12V fused feed, and ground.
In practice most of the radios (4 of them) use a common bolt to the
frame, but indipendant leads to that bolt.  The other is just a cheap
cb, and uses a 1/4 inch jack for power.  The ground for that, I forget
right now where that goes, but the antenna is also permanently fixed to

The vehicle I have, is a diesel Land Rover hybrid I built, well, most of
it came from Solihull, at one time or another, but the electrical system
is my own creation, after much thinking as a result of the wiring loom
fire I had.  (Solihull used not to fuse the main lighting circuit, so
when a wire chafed through somewhere in the back after 20 years of
bouncing down the road...  Whoosh!...)

I now have more fuses than I remember, each system has it's own feed, of
those that in turn have a common feed point, engine electrics, aux,
lighting, radios etc, those common points also have a main fuse.  There
are also two "Mega" fuses that feed the whole vehicle.  Much of it is
also monitored, if a critical fuse fails, a warning lamp comes on.
(Just wired across the fuse)

The "Frame" or chassis, is made from 3mm steel, and galvanised.  That's
where all the "Grounds" end up...  Hopefully, it shouldnt corrode in my
lifetime and cause problems.  I also coated each of the grounding points
with bitumous sealant when I built it 3 years ago to keep water out.  So
far, so good...

Radios...   IC706mk2G + LDG auto ATU, Ascom SE550 (70MHz), TH-D7,
antique cb, and the broadcast jobbins...  There is also a free fused
feed for RAYNET if needed, separate regulated and backed up feeds for a
GPS (eTrex) and external active puck antenna.  As well as 4 aux
uncommitted power sockets.  Two cig' lighter type, two 1/4 inch jack.

A 240V inverter is in there too, only 250W, but enough to charge a
laptop or phone if 12V adapters not available.  I have run a 500W
electric drill from that, but it howled at me when the thing had to "do
some work" Hi...  Didn't blow up though...

I do need to add some more power points in the back for camping gear
etc, more little job's.

The main battery isolator has a 30A fuse across it, so things that need
24/7 power for memories etc can have it, but if someone tries to hot
wire the thing, the fuse will blow, and darkness will reign!...  (I've
actually thought of wiring a sounder across that too, just to scare the
$41t out of them, but so far it's only me who's tripped it, forgetting
the big key :)

APRS works well, either the D7 and eTrex on their own, or with this
laptop and ui-view.  I have a 12V power unit for this, that develops the
regulated 15V at 5A it needs!...  The D7 is not adversely affected by
the use of the IC706, but you can hear the 706 desense on 2m when the D7
sparks up.  I've had no trouble with RS232 and electrical noise, even at

All good fun...

I need to finish the second battery install one day soon I think...

I also think I need to get a life!...


Dave G0WBX.

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