celandine
Active member
Can I cut the cable from the scanner and then rejoin it with an appropriate junction in order to make installation and subsequent mast removal easier? If so what kind of coupling is best?
JRC radar cable cut or not?
- Thread starter celandine
- Start date
gremilius
New member
Did this 6 weeks ago. Cut cable, used plastic block connectors to join. No problem so far.
yachtbits
Member
if you do cut it and use terminal blocks to re-connect. I would suggest putting the terminal block into a junction box to prevent moisture ingress. Pass the cables through plastic cable glands into the box. This will also help prevent disconnection caused by strain on the cables.
One point to note though, cutting the cable may void your warranty if the system is new. Speak to the supplier first.
Any problem getting a junction box and glands drop me an email and I'll help you.
www.yachtbits.co.uk
sales@yachtbits.co.uk
marine electrical/electronics specialists
One point to note though, cutting the cable may void your warranty if the system is new. Speak to the supplier first.
Any problem getting a junction box and glands drop me an email and I'll help you.
www.yachtbits.co.uk
sales@yachtbits.co.uk
marine electrical/electronics specialists
numenius
New member
NO!
No No No! Put those cutters away! The danger would seem to be if you end up altering the length by even a mm.
I asked this very question of a friend who installs and repairs radar for part of HMG about my own radar. Once he'd stopped spluttering when I said I was going to shorten my cable, he tells me that cable lengths are supplied in multiples of the wavelength and so untrained cutting will end up with an incorrect length (and presumably wrong SWR) resulting not only in possible damage, but certainly in reduced performance. His opinion was that it would create a "hot spot" (quite literaly he tells me) in the cable. His advice to me was to coil it (the surplus) - but NOT in a circle obviously (else you'd create a lovely magnetic field) but in a figure of 8 thus cancelling out the any magenetic effect created. Suggest that it may be worth consulting the manufacturer or a proper installer before cutting. Its probably possible to do it OK - its just that altering of the length by even the most minute amount seems to be the danger.
http://members.lycos.co.uk/boaty1965/index.htm
No No No! Put those cutters away! The danger would seem to be if you end up altering the length by even a mm.
I asked this very question of a friend who installs and repairs radar for part of HMG about my own radar. Once he'd stopped spluttering when I said I was going to shorten my cable, he tells me that cable lengths are supplied in multiples of the wavelength and so untrained cutting will end up with an incorrect length (and presumably wrong SWR) resulting not only in possible damage, but certainly in reduced performance. His opinion was that it would create a "hot spot" (quite literaly he tells me) in the cable. His advice to me was to coil it (the surplus) - but NOT in a circle obviously (else you'd create a lovely magnetic field) but in a figure of 8 thus cancelling out the any magenetic effect created. Suggest that it may be worth consulting the manufacturer or a proper installer before cutting. Its probably possible to do it OK - its just that altering of the length by even the most minute amount seems to be the danger.
http://members.lycos.co.uk/boaty1965/index.htm
LadyInBed
Well-known member
I asked the same question on Mon Oct 15 00:25:53 2001
Do a Forum search for:
Radar – to cut the cable or not
The general concensus is that 100's/1000's of cables have been cut to size with no adverse effects. The best advice I got was to leave the cable intact, then cut it when/if I ever drop the mast.
As to the SWR issue, the cables are made to standard lengths. I would be amazed if they coincided with the VSWR of any of the signals.
Do a Forum search for:
Radar – to cut the cable or not
The general concensus is that 100's/1000's of cables have been cut to size with no adverse effects. The best advice I got was to leave the cable intact, then cut it when/if I ever drop the mast.
As to the SWR issue, the cables are made to standard lengths. I would be amazed if they coincided with the VSWR of any of the signals.
ArthurWood
New member
The instructions for my JRC 100 indicate that the cable may be cut (doesn't say shortened). There was an article in MBM about 18mo ago which included cutting during installation on a power boat. They used a special connector to rejoin.
jtwebb
Member
I did cut the cable to a JRC 1000 I fitted some years ago. I checked with the importers first who said there is no problem. There are two coaxial cables inside which must be handled with care as they are quite delicate. The cable only carries the 12v feed, control cables and basic video. All radar signals are handled in the scanner. The main problem was ensuring good support against vibration. I used strip connectors but the more expensive type with little tongues under the screws. The cheap ones screw straight onto the wire and cause damage as they rotate.
J Webb
J Webb
brianrunyard
New member
It's common practice to shorten the cable. Most fishing vessels I know have done this with no problem, and they probably use their radar far more than any of us.
The usual method is to mount a plastic box with glands for the cable and connector blocks.
I shortened mine from something like 40ft to about 5ft.
Brian
http://homepage.ntlworld.com/brunyard
The usual method is to mount a plastic box with glands for the cable and connector blocks.
I shortened mine from something like 40ft to about 5ft.
Brian
http://homepage.ntlworld.com/brunyard
G
Guest
Guest
Re: NO!
Your friend would be correct if there were any transmitted frequencies passed through the cable. As this is not the case with JRC 1000 radar because the header unit manages all of that and sends a video signal back to the radar. Such signals are not modulated onto a carrier frequency and therefore will not create "hot spots" etc in cables and/or components. Your friends advice is sensible however in respect of the many who make bad connections and terminations who would be far better off leaving the able rolled up. In short the dealers are correct. You can shorten the cable but make a good job of your connections. For the record I have jointed the cable for my JRC 1000 under the mast foot and it runs perfectly.
Your friend would be correct if there were any transmitted frequencies passed through the cable. As this is not the case with JRC 1000 radar because the header unit manages all of that and sends a video signal back to the radar. Such signals are not modulated onto a carrier frequency and therefore will not create "hot spots" etc in cables and/or components. Your friends advice is sensible however in respect of the many who make bad connections and terminations who would be far better off leaving the able rolled up. In short the dealers are correct. You can shorten the cable but make a good job of your connections. For the record I have jointed the cable for my JRC 1000 under the mast foot and it runs perfectly.
celandine
Active member
Many thanks to all. Your answers have been most helpful.
Mick
Mick
celandine
Active member
Many thanks for the replies; they have been most helpful.
Mick
Mick
G
Guest
Guest
Hmm, I HAD to cut mine when I experienced a 'problem' with the mast and was wondering how to re-join it. Is it not necessary to maintain the screening around the various pairs? I was toying with the idea of a cluster of phono-plugs!
