New radar - old cable???

[demonboy]

We are replacing our 20yr old CRT Furuno 1800 with the much smaller Furuno 1623.

I'm really hoping that someone out there can tell me it's ok to keep the old cable and wire it up to the new unit because the idea of threading a new cable up the mizzen is filling me with dread!

I've been told the main concern would be the inadequate guage of the individual wires causing voltage drop issues, but I'm certain the older cable uses thicker wire than the new one, so would this be a problem?

Is this a viable option or have I got to dedicate the next 2 weeks to feeding my new cable up the mast?

 

[homa]

Surely if the new cable is thinner than the old existing cable then you should have no problem?

 

[demonboy]

One would assume so. I just want a sparky out there to tell me 'yep, no problem'.

 

[Malcb]

Are the connectors the same, also the wiring of those connectors.

 

[demonboy]

No, the connectors are very different. It would mean chopping the cables at both ends.

 

[boatmike]

Very simple solution.
Securely tie a "messenger" which can be a strong piece of cord, to the bottom end of the existing cable. Up the mast then and pull the cable out of the top till you get the end of the messenger out of the hole. Then attach it to the end of the new cable and feed it down while your buddy pulls from the bottom.
When you attach the messenger prepare the end of the cable first by cutting off any connectors (the bottom end should go to a junction box anyway) and soldering a secure loop in the end to tie the messenger too. It's embarrassing if it comes undone half way /forums/images/graemlins/blush.gif Then use insulating tape to wrap around the joint to stop it catching. Very easy.

 

[Malcb]

Then IMO bite the bullet and run the new cable. Surely you can use the old cable to pull through a mousing line or even the new cable.

I've just installed a Furuno 1623 and someone suggested that I cut the cable /forums/images/graemlins/mad.gif to make it easier when (if I ever) I take the mast down.

There were 2 red wires and 2 black wires and the narrowest co-ax/screened cable that I have ever seen. The wiring diagram in the Furuno handbook just shows numbers and not wiring colours, so you have to use a magnifying glass to read the numbers on the plug/socket.

I managed to rejoin it to test the system, but I have since sourced a replacement (from the US) and will be fitting that next week.

 

[demonboy]

Thanks for the advice on the messenger trick, though I have done this already with the Navtex aerial.

What I wanted to know was whether I could just use the existing cable: is there an electrical reason why I can't do this?