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Best coax for field-expedient station?


Skunkworks

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So I am currently using 25 ft of RG8 for my "field" set up, and I'm wondering what would be a better/best replacement coax.

I am usually using a 3-elelment yagi on a 20ft telescoping flagpole and a 50W radio at the back of my truck, but sometimes 20W or even 5W.  So 25-30 feet is really all I need.  I may use a 30ft pole in the future, but for discussion's sake, I doubt it matters.  I would like it to be flexible (not LMR400) for ease of use.  I also will be setting it up and taking it down often, so for durability, hard-line would be a bad choice I imagine.  I'm not afraid to spend a little to get something good, but don't want to throw cash at something for no noticeable gain either.  Any recommendations and real-world experience?

 

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1 hour ago, Skunkworks said:

So I am currently using 25 ft of RG8 for my "field" set up, and I'm wondering what would be a better/best replacement coax.

I am usually using a 3-elelment yagi on a 20ft telescoping flagpole and a 50W radio at the back of my truck, but sometimes 20W or even 5W.  So 25-30 feet is really all I need.  I may use a 30ft pole in the future, but for discussion's sake, I doubt it matters.  I would like it to be flexible (not LMR400) for ease of use.  I also will be setting it up and taking it down often, so for durability, hard-line would be a bad choice I imagine.  I'm not afraid to spend a little to get something good, but don't want to throw cash at something for no noticeable gain either.  Any recommendations and real-world experience?

 

M&P Ultraflex or Hyperflex 10 is the same diameter as LMR400 or RG8 (not to be confused with RG8x), but has stranded center conductors for greater flexibility. They also make a 7 mm variant but with greater losses of course.  What's nice is that they make a POTA coax that's brightly colored to help prevent accidents and make it harder to lose.

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1 hour ago, WRXP381 said:

Wow how far are you trying to talk from your truck?  I just use a good radio and antenna and easily go 100miles.  If I need to go further and just drive up a hill.  

Thank you for that helpful bit of advice. 🤔  SMH

I always want to be able to talk further.  I live in a very wooded area and have a fair amount of hills, so every advantage is helpful.  There are no repeaters nearby and sometimes I want better simplex communication (like at the hunting camp).  I'm using a good antenna and a very good radio.  I just don't want to handicap myself by using crap coax.

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You should be fine with RG8, LRM400 and equivalent, and the M&P cables @SteveShannon mentioned  with a coax cable of 25-30 feet. I did calculations using 30 feet of RG8 and LMR400 using the kv5r coax loss calculator  I used an antenna with 3 dBd of gain. This was with a 25 watt radio. 

RG8 -  36 watts ERP

LMR400 - 41 watts ERP

Remember that antenna manufacturers advertise using dBi which is higher than dBd. The kv5r calculator uses dBd. Subtract 2.14 from the dBi to get the dBd.

Most coax is going to pretty lossy on UHF frequencies, there is no way around that. Unless you want to spend big money for the proper air core coax cable like used on towers.

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