Joining co-axial aerial cable and connecting to GPS

[Humblebee]

Hello all, I'm stuck with a problem with my GPS set, a Navman Tracker 5505 with separate aerial. At some stage the thin co-axial cable leading from the aerial has become disconnected from the main body of the unit and there is no connecting terminal. Also the cable has been cut in the cabin, some two feet away from the unit.
I have been able to touch the outer and inner parts of the cable to the unit and can confirm that the unit is receiving signals and working as it should. However, I have been unable to find a way of making satisfactory permanent connections. All I have learned so far is that a much thicker grade of co-axial cable can be fastened securely to the GPS - the inner core fits in the female end at the unit and the outer core wraps around the outer part.
It seems I need to find a way of extending the aerial wire from where it ends in the cabin and then securing it to the unit. Navman suggest buying a complete new aerial but this, as you would expect, is a bit expensive.
Are there any connectors for joining co-axial cable of different sizes? Or some other way of making the connection? Or am I going about this the wrong way?

 

[elton]

I would solder it. Solder the inner cores and slide heat-shrink sleeving over the junction, then carefully solder the outer braiding in several places so it surrounds the inner core junction. Finally slide a bit of heat-shrink sleeving over the braiding junction. If you aren't skilled at soldering, practice on something disposable first.

 

[VicMallows]

I agree with Elton. In theory it is not ideal to join two dissimilar bits of coax in the middle of a run, but in practice at the frequency involved here it is unlikely to make the slightest difference.

 

[rosssavage]

And yet just about all manufacturers insist on supplying cables pre-terminated... All my GPS cables had to be cut to fit through two 10mm stainless plates holding my radar arch on. No way could I cut 15mm holes through that to feed the plugs through. I used BNC connectors, but soldering will be fine.

If you choose BNC connectors, you will need to buy the correct crimping tool to install them. (Not expensive, but you'll only use them a few times ever probably...)

 

[William_H]

And yet just about all manufacturers insist on supplying cables pre-terminated... All my GPS cables had to be cut to fit through two 10mm stainless plates holding my radar arch on. No way could I cut 15mm holes through that to feed the plugs through. I used BNC connectors, but soldering will be fine.

If you choose BNC connectors, you will need to buy the correct crimping tool to install them. (Not expensive, but you'll only use them a few times ever probably...)

Or use BNC soldered connectors. Actually only the pin needs be soldered on. Delicate and tricky job needs practice. The outer screen is clamped tot he connector. But a male and female connector to join cable. Or as said just solder the cable.
good luck olewill

 

[rosssavage]

Yeah, you can solder the BNC connectors, but it isn't easy!!

I tried, gave up and crimped eventually.

 

[VicMallows]

You can even get twist-on BNCs which don't need crimp or solder They work well enough on suitable coax, and are very useful for a quick or 'emergency' fix.

 

[forelle541]

I swapped the external aerial for a cheap internal one off eBay. Worked a treat with my Navman tracker.

 

[Humblebee]

I would solder it. Solder the inner cores and slide heat-shrink sleeving over the junction, then carefully solder the outer braiding in several places so it surrounds the inner core junction. Finally slide a bit of heat-shrink sleeving over the braiding junction. If you aren't skilled at soldering, practice on something disposable first.

Thanks Elton, I think that's what I'll do, or at least try first!

 

[Humblebee]

You can even get twist-on BNCs which don't need crimp or solder They work well enough on suitable coax, and are very useful for a quick or 'emergency' fix.

Thanks Vic, that's now option 2 on my list.

 

[eddieperkins]

I accidentally cut through my GPS aerial once and joined it with standard F connectors that are used on satellite systems, worked just fine.

 

[lw395]

All these cheap connectors will usually work just fine, but it's important to keep coax cables sealed against moisture if long term performance matters.
The simplest (quality) connectors for DIY are the sort where you solder the centre pin then clamp the outer using spanners. Rubber gaskets seal the cable.
You can get these in BNC, SMA, N and others. For small cable, I'd use SMA, then get an adapter to whatever the equipment needed. Bigger cable I'd probably use BNC.