Survivalism & Self Sufficiency Topics > Amateur Radio How-To's

best practices for making coax patch cables?

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backwoods_engineer:
Years ago, at a surplus sale, I came into a good deal on a nice long roll of Belden 9913F, a 50-ohm coax that is a lot like LMR-400 loss-wise, the same diameter as RG-8X, but more flexible.

That has lasted me until now.  I make all my ham radio cables from HF to UHF out of that.

I always use either crimp or solder silver-plated PL-259's or N male connectors.  I am leaning toward all crimp now, because they seem to weather better (crimp connections as gas-tight).

armymars:
  Good cable is important for other reasons. I have bought cheep RG8X to make jumpers. The problem was the center conductor would break if flexed too much. Look Ma no conductivity. The old foam centers found in co-ax was open cell foam so any moister would follow along the length of it. That was before we had "Coax Seal" and other products to take care of it. If you didn't use these products to seal the ends (just tape) it would not be long before you had trouble.
  9913 has other problems if not sealed with a gas type seal. As the atmospheric pressure changes it would drive air in and out of the co-ax which is mostly empty. If wet air went in then it would leave the water behind when it came out. The engineers have a name for this, but I can't remember it. I once built a 2 meter beam and sealed the brazing rod elements thru the PVC boom with a glue gun. work great for two week then wouldn't take power. I pulled out an element and pored a 1/4 cup of water out of it. No joke. No rain during the two weeks. Surprise!
  In Europe hams like to use 75 ohm co-ax to match the antennas then a tuner to the radio. More later diners on the table.

PrepperJim:
Thanks for this thread. I had exactly the same questions as Smurf....two years later.

scoob:

--- Quote ---In Europe hams like to use 75 ohm co-ax to match the antennas then a tuner to the radio. More later diners on the table.
--- End quote ---

Interested in the follow up on 75ohm.  I inherited a spool of catv coax, and was wondering if it's worth using as hf or vhf feedline, or is it scrap?  (I'm not in Europe though)

Also, on the OT... patch cables between tuner/radio/meters/etc.:  are there special considerations for building cables with such a tight bend, or minimum cable lengths between devices that should be maintained?

Smurf Hunter:

--- Quote from: scoob on March 28, 2016, 09:35:40 PM ---Interested in the follow up on 75ohm.  I inherited a spool of catv coax, and was wondering if it's worth using as hf or vhf feedline, or is it scrap?  (I'm not in Europe though)

Also, on the OT... patch cables between tuner/radio/meters/etc.:  are there special considerations for building cables with such a tight bend, or minimum cable lengths between devices that should be maintained?

--- End quote ---

Personally I think rg8x is the best all rounder.  It's thin and easy to bend, and unless you have a considerable distance is tolerable loss on VHF, and I just accept the loss for the little UHF work I do.

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