I have a piece of 75 ohm coaxial cable of unknown type (outer diameter is around 7 mm) which has developed a breakage in the center conductor (which is stranded). This cable is an adapter cable which connects my RG-6 type coaxial cable to my RTL-SDR card.
As far as I understand, the best way to solve the issue would be to simply replace the cable with another cable of higher quality. Unfortunately, this solution is not applicable to me, since the ends of the cable are attached to connectors of types which I can't easily obtain. The card end uses MCX connector and the RG-6 end uses a type of Belling-Lee connector suited for work with thin coaxial cables.
Second idea that came to me and which I used with success with some other coaxial cables is to cut out the middle, damaged, section and leave short pieces of cable near the connectors I can't replace. After that, connect easily obtainable connectors to the healthy ends of the cable and mate the new connectors or use another coaxial cable in the middle.
SMA and RP-SMA connectors come to my mind here, but the problem is that they are 50 ohm connectors in general. I also don't have the tools to install them and this one-off repair doesn't justify obtaining such tools.
Another idea that I like the least but am currently most likely going to go with would be to directly connect the two healthy ends of the cable. Solder together the inner conductors, cover the joint with heatshink tube, then carefully solder together outer braided conductors and cover them in heatshrink tube as well. Problem here is that I don't like the reliability of the resulting work. A variation of this theme would be to solder the healthy ends of the existing cable to a new piece of a different, but similar, coaxial cable. The effect of this is that I'd have more room to work with.
Finally the worst solution I see right now would be to replace the connector on the card which uses the damaged coaxial cable with an SMA connector. The problem with this is that SMA connectors are in general 50 ohm connectors and this is a 75 ohm system.
So my question is basically how do I repair this cable? Which of the options I could work with is the least bad and are there any better ideas I didn't think of?