Easy way thru firewall?
 

I'm installing a ham radio in my Ranger and need to wire it directly to the battery. Obviously the radio will be installed inside the cab of the truck. Is there an easy way to get the wires through the firewall without having to drill any new holes? The truck is a 2002 Ranger, 4.0, auto. The antenna, at least for now, will be a magnetically mounted one.

Any suggestions would be appreciated.

Yes. DON'T wire it directly to the battery.

Find a hot wire near or a hot terminal in the fuses in the cab.

I considered this but the instructions that came with the radio state to wire it directly to the battery. The wires supplied with the radio are fused. I am not clear on the advantages/disadvantages of one method versus the other with respect to function, but am assuming the radio manufacturer suggests this method for a good reason. Any thoughts?

The biggest danger that I can come up with is having the power wire short out somewhere before the fuse.

You want to make sure that the wire is rated for the harsh and high temperature environment under the hood. It can be weakener by vibration or nicked by a sharp edge.

If you do it, you want to verify the quality of the wire and use tie downs at various spots to keep it safe. Maybe you could tape it to a bundle that's routed toward ths firewall. Or else, you could protect it with some of that ribbed plastic tubing.

Also, you want to protect the hole with a grommet, if you end up drilling your own.

I have seen battery clamp devices to allow for extra connections -- probably for high power amps, etc. Once again, you want to go with some pretty good stuff. You don't want to have a no start because the connection device somehow gave you a bad connection.

I'm sure that they want a battery connection to ensure that there's a solid power source for transmitting. You might be able to find an equally good source at the fuse box and save yourself a lot of hassle. You could always try that out first -- just don't shorten your wires until you verify that it works.

But, I would think that you could wire it up to the battery if you're careful.

Note, these are just opinions for your consideration.

BTW, what's the power rating? I know that since electronic ignitions, there are restrictions. In the old days, I've heard that some guys ran a full KW mobile. Hard to imagine.

Good Luck,

hj

Seems I recall in the CB world, [no rocks please], that by wiring directly to the battery, you limit the chance of electronic noise from the radio. I've heard of noises caused by the alternator. It's a sort of a whining noise, that increases with engine speed. There is some sort of filtre designed to take out that noise, but why bother, when you can wire direct to start with?:-drink

What I did on my 2005 for switching the work light in the back to get through the firewall is pierce a small hole in the rubber boot you can see near the brake booster. Hope this helps, remember use good insulated wire and fuse close to power source.

Thanks for the tips.

The radio is 50 W and one of the guys at work suggested using 10 gauge stranded wire. So the power output isn't that high, but 10x that of a CB or handy talkie. A guy at work who is into ham and electrical stuff also stated that it was to limit the whine that often results due to alternator noise, etc. Fuses will be installed at the battery side and the radio side of the wiring.

I need to get under the truck and look around some more, but right now I'm leaning towards drilling a hole, and wiring through that. I will use a grommet. Hopefully I can work on it Monday or Tuesday. I'll post what I did if anyone is interested.

I found an unused high current lug on the inside fuse panel. IIRC it was #36.
It is a battery source with what looks like #10ga wire behind it.
I added a 15 amp circuit breaker from there to to supply a 150 watt transmitter.

If you really want to keep rfi out of the Cb then use shielded power wire. Fuse it directly off the power source (I usually use the hot side of the solenoid on the fender well that is usually within a foot of the battery.)