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Damaged Antenna Cable Performance Question



I have a 50’ length of LMR400 cable that has sustained some insulation damage.  (If you don’t mind, I won’t go into how it became damaged – will save that for a later post).  I’m wondering if it is performing as well as it needs to be for GMRS use?  Maybe there are people on this forum with some experience in using a damaged cable that can chime in.  Here’s some needed information before you can answer:


Description of cable:

As I said, the cable is 50 feet long.  It is 50 ohms, LMR400 equivalent (labeled Bolton400), heavy-duty, low-loss coaxial.  It has N-type male connectors on each end.  I use N-Type to UHF converters to connect to my radio and antenna.  Approximate price: $60.


Description of damage:

The outside insulation damage appears to be about 1 inch long by about ¼ inch wide (does not go all the way around the cable).  The braiding layer appears to be scratched, but completely in tact (not torn through to the next insulation layer). 

Here are four possible solutions:


Possible solutions:

Solution 1:  Do nothing.  The cable works now (although performance is in question).  Price: $0.


Solution 2:  Abandon the cable, bite my lip and purchase a new cable.  Price: $50-$60.


Solution 3:  Cut off the bad section of the cable (about 10’ from one end) and the other connector as well, and mount two new PL-259 (UHF male) connectors on both ends leaving 40’ of pristine cable, which is still about 10' more than I need.  Replacing the N-Type connectors allows the elimination of the two existing converters at either end.  Price: $20 (per quote received from a local cable company that specializes in radio cables).


Solution 4:    Same as above, but leave good side N-Type connector and mount new N-Type connector on cut-off end.  Price: Uncertain (but should be less that solution 3 above).


Additional Information:

Solution 2 involves ordering, substantial cost, waiting for shipment, and then installing new cable.  Time consuming, but doable.  Solutions 3 and 4 involve removal of the old cable, driving about 25+ miles (each way) to cable shop, and re-installation.  A fair amount of time/work.


Right now, the cable seems to be working, which leans me towards solution 1.  But I’m basing this on my own (imperfect) perception of Tx and Rx performance.  I don’t have any meters or test equipment other than a standard VOM.  On the other hand, if the cable is in fact NOT performing as well as it would before being damaged, should I pursue one of the solutions 2-4 above?


Thank you in advance.


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I would do 3. But I have the tools to do it. The losses from the connectors isn't going to be huge.




Personally if I was feeling lazy. I would patch repair it, if everything checked out. I would fill the cut ( I imagine a cut) with silicone all-weather adhesive (gasket former) style rtv. Then over wrap 2x with self almagating tape. Going several inches past the wound on both sides. Then a final 1/4 stretched wrap with a uv stablized electrical tape. We always used 88t when we where doing telephone work. Got yelled at a lot by the bosses for calling it electrical tape.


Sent from my SM-G975U using Tapatalk


Edited: because you know using the phone.

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If the cable is exposed there is a good chance its done b/c once air gets inside of LMR400 the rusted braid will act as a giant noise PIM generator when rubbing the shield foil.


I would just replace the cable with something new, silver plated N connectors at the very least. Heck, I would just use that as an excuse to ditch the LMR400 and go with a FSJ4-50B Heliax feedline... best move I ever made, btw.



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