Chartplotter Co-ax Cable question

[dansyerman]

To avoid surface mounting or drilling big holes to accomodate the end fitting on the transducer cable, I was wondering whether the cable might be cut, drawn through an existing cable run and then joined again? Is the risk of performamce loss in the Lowrance Chartplotter too great (or making a mess of it). I don't know too much about joining co-ax to assess risk and opinions wuld be appreciated and on how to join again if it's possible.
The boat is a sadler so double skinned etc.
regards

DJ

 

[rob2]

You don't say what diameter the cable is, which might dictate the options open to you. Some will say there will be some attenuation of the signal, but in my experience a single extra join should be acceptable.

Assuming the cable is routed out of sight, there is really no problem soldering the central conductor back together and then bridging the gap between the screens soldering on an insulated wire. You must, of course ensure there is no risk of shorting between the outer and inner - best to sleeve each join with shrink sleeve tubing. Don't make the join where the cable may get flexed as it will be slightly weaker than the original continuous cable.

My own preference is to use male and female bnc crimp-on plugs, especially as if thoughtfully placed it will allow the unit to be removed without having to totally remake the join. I believe they should be 50 ohm types.

Rob.

P.S. It may be possible to use a bulkhead FF fitting with a male on each end of the cable if that helps in allowing the parts to be drawn through.

 

[ffiill]

When I was fitting antenna coax for my GPS after first checking the type of plug and its availability just cut off at plug end;used amount of cable needed; cut of surplus and then fitted a new plug.

 

[st599]

When I was fitting antenna coax for my GPS after first checking the type of plug and its availability just cut off at plug end;used amount of cable needed; cut of surplus and then fitted a new plug.

Which is fine as long as the coax isn't part of the tuned circuit. Soldering the two ends will create a mismatch in the transmission line. Better to use connectors.

 

[dansyerman]

Thank you for the comments guys, much appreciated and food for thought on how to proceed.
Rob2 - the cable is about 5 or 6 mm diameter.