Need assistance extending power and coax on mobile install

[bkspear]

Hello all,
I am attempting to install a mobile dual band radio I just got and would like to some help with extending some cables. The included power cables are not long enough to reach from the radio mounting point to the battery. They use the t-connectors, how would I best extend these cables or splice in extra length? I also have a mag-mount antenna - Nagoya UT-72 - which again, the provided length of coax is not long enough to reach from the back of the truck to the radio in front. The coax seems to be factory connected to the mag-mount side, so again, what is the recommendation to extend or splice in additional coax? Thanks!!

 

[N4GIX]

Buy some red/black wire of the same gauge, then solder and tape them together, or use heat-shrink tubing to provide a weather seal. Do not use crimp connectors, as they are prone to corrosion and eventual failure.

For the antenna cable, assuming a PL-259 connector, you can use a barrel connector, and an extension of the approximate length needed with PL-259 on both ends, or an extension with an SO-239 (female) on one end, and PL-259 on the other end. Wrap the connectors with electrical tape to keep out moisture and contaminants.

 

[KC4RAF]

+1 with what Bill posted, but one additional

advice; don't use wire nuts either. Wire nuts and mechanical connector as mentioned corrode and become loose over a period of time.

 

[N4GIX]

When I owned my own GE dealership in southwest Texas, I just loved "crimp-connected" power wiring that some numbskull had used...

...when I could charge the minimum one hour labor for a five minute job with a soldering iron... LOL!

 

[AK9R]

I've moved this thread to the Radio Equipment Installation forum where it will probably get more general-purpose exposure.

 

[FKimble]

I would go with a heavier guage of wire than factory installed especially since you are having to extend it. I would cut off the existing wire about a foot from the "T connector" and splice in the heavier guage to prevevent voltage drop. Now if you only need to add a couple feet this may be moot. And be sure there are fuses on both wires near the battery end. Actually just past the fuses to keep from having to add back fuses at the radio end.

 

[dsalomon]

I'd like to add that you should use tape that's not only weatherproof, but also heat resistant, depending on where it's going to be routed under the hood. Plain old electrical tape melts at a surprisingly low temperature and also will not stick under sustained high heat. Go to an auto parts store and ask for the appropriate tape. If you use heat shrink tubing, use a type that's also rated for high heat (again, the auto parts store).

A few more things to take note of. Make sure that you don't route any cables where they can get crimped by any moving part (i.e. a door or hood either opening OR closing). Just one accidental crimp with a door or hood can wreck an otherwise good installation. Also, check the antenna height before making it permanent depending on your parking situation. It suck to have a remove an antenna every night before pulling into your garage because you mounted it in a location where it's too high to fit in the garage.

Finally, it appears that you are currently planning for a VHF/UHF ONLY rig installation. You might want to consider how you would do things differently if that rig were to be eventually replaced with a HF/VHF/UHF rig or have one added in addition to the current rig. You might consider heavier gauge power cable, one that would support a VHF/UHF + HF rig (or two rigs). You might also think about your coax routing options. Your HF antenna will probably be in a different location than your VHF/UHF antenna. However, maybe part or all of the coax routing might be traveling down the same path. Even if they might be going down different paths, you still might consider routing HF coax now and leaving it terminated on both ends. A lot of the work installing coax is getting other stuff out of the way, or making a path for it. Thinking about that and doing that is better done once than twice, if possible, and might also result in an overall cleaner installation.

Some of my suggestions might be considered overkill by some. However, I've installed many ham rigs in many vehicles and I've never had an installation related failure. Inside a vehicle is a harsh environment. Plan accordingly. Overkill is better than not enough.

73 - David, AG4F

 

[Project25_MASTR]

So there are a few things to look at here. What I'd generally suggest is cutting the T connector off and recrimping with power poles. Reason being, these are a lot more common as a universal power connector in the amateur radio world. Now if we were dealing with commercial applications, I'd honestly recommend the SAE connector Motorola uses (as it is often found for accessory power in agricultural equipment).

Running your own power as splicing the line is a bit of a pain though easy and straight forward. Crimping versus soldering...generally soldering is frowned upon in the automotive industry (vibratiion causes the solder to fatigue, crack and eventually fail) but if done properly it can outlast the vehicle...same can be said for crimping. The amateur radio industry suggests fusing both sides and connecting to the positive and negative leads of the battery. The commercial industry runs fused positive with unfused ground. Personally, I prefer this method assuming you have a negatively grounded vehicle.

Now coax, one important item of note is what coax is your Nagoya using, RG58 or RG174? You can add pieces in, but you are also adding more loss. So sacrifice convenience for signal (just like trunk versus roof, mag versus permanent).