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NEW: Mobile Antenna Testing Results Part 1

Updates:

Oct 2004: finishing up the mobile antenna shootout

July 2004: Added antenna testing and more photos

June 2004:
Laptop crash so I decided to completely redo the site..

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This is what I did for power. I am not willing to say this is perfect, but it is what works for me.

Objectives

First the system has to be safe. Riding on an EMS crew, I see too many car fires that come from inadequate electrical systems used to run electric snowplows. I was going to have none of that. Extensive fusing and safety precautions were taken. Wires are kept away from hard edges and are clearly marked. This goes hand in hand with a maintainable design. so the wiring is well documented.

Second: I wanted reliability. Connections had to be locked in place by screws. Wire to Wire connections are all soldered. Wire bundles are tie-wrapped and secure fastened to the vehicle.

Third: I wanted performance. Minimize voltage drops as much as possible.

Design:

The truck comes with two batteries mounted up front. The radio is behind the front seat and at 100W will pull 15A or more. It does not take alot of ohmic losses to lose a volt. So I ran both a hot (red) and ground directly from the battery to behind the rear seats. The battery isolator is in the engine compartment. This unit senses if the third battery needs charging and if it does, connects it to the primary battery. (In my case “batteries”) In addition it can be manually controlled to connect the third battery to the others to provide a jump start. (Luckily I have never needed this function.) The wires to the “power distribution panel” is by this pair of #4 wires. This charge isolator is much better than a set of diodes but at a cost.

The “power distribution panel” is a 2’ by 2’ piece of plywood behind the rear seat. This is right next to a gell, marine battery mounted securely here as well. Given the battery isolator, there is no way that this battery connects to the front two unless I tell it (with a switch) This assures that if there is an accident and the front batteries are cut out to prevent the airbags from discharging, the third batter will not provide “sneak power” to the airbags.

I have screwdown strips mounted on this to which each piece of equipment gets power. Incomign power is fused again here and distributed using #4 and #8 wiring using components commonly used for high end car audio equipment. All wires are properly coded (red/Black) Some loads are relay controlled from the switch box mounted in the front (the PA/Siren, Emergency Lights, Front driving, Rear extra backup lights) From this panel I have about 2 feet of wire to the TS-B2000. It is all set for an amplifier if I need it.

Still to do:

I would like to put in some voltage monitoring. I am looking for a small computer that might work as a control center. (APRS, messaging, station control, antenna control, power monitoring) I will figure out something! Might just end up installing some meters!

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Copyright 2004 by Philip P. Thompson, All rights reserved.