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Coax loss

Discussion in 'General Ham Radio Discussion' started by KD2GOE, May 25, 2019.

  1. KD2GOE

    KD2GOE W9WDX Amateur Radio Club Member

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    Tested with my friends bird meter with the same results.


     

  2. 543_Dallas

    543_Dallas Sr. Member

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    Sounds reasonable. Are you going to buy new coax and try to get the 3 watts back?
     
  3. Jay Mojave

    Jay Mojave Well-Known Member

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    Yeah 543 that's a good call, as it might be more money and time to get a few watts back as compared to a 2.5 dB total gain in performance. This maybe considered not enough dB's or watts to worry about.

    The guys who jam each other and take away others enjoyment of the hobby, this would be death.

    I needed to access one of the extended range UHF repeaters here in the desert during our last fire season. I had a 100 Ft piece of old radio shack RG59 75 ohm coax in the weeds. Soldered on the PL-259 connectors with out the proper coax adapters and up went the antenna on a 10 Ft pipe. I hit the repeater 25 miles away ok and it came back full quieting, good deal so now I could listen to all the local fire talk.

    I am sure the old radio shack RG59 coax had plenty of insertion loss, at the UHF frequencies, but still allowed me to operate within needed "Link Budget" with plenty of headroom. What's a few dB's amongst friends?

    Jay in the Great Mojave Desert.
     
  4. KD2GOE

    KD2GOE W9WDX Amateur Radio Club Member

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    No i am not. I just wanted to know if this sounded excessive that was the point of the post.
    You can look at data sheets all day long but it never accounts to real world install.

    I am just testing every thing before a replace this Junk Diamond x50 antenna that gets its ass handed to it by a Tram 1180.
     
    #19 KD2GOE, May 31, 2019
    Last edited: May 31, 2019
  5. 543_Dallas

    543_Dallas Sr. Member

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    I think you're good to go. The calculator I posted earlier was very close to what I measured on a length of lmr400 (JEFA tech brand) with a bird 43.

    I was curious and tested it when I was having problems with my 2m/440 antenna. The antenna was a knock off of a diamond. It worked ok until it got full of water.
     
  6. nomadradio

    nomadradio Analog Retentive

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    I'll never forget the first 440 MHz transceiver I set up to use. Made a home-brew ground plane on a SO-329 socket to put on the roof. The only coax I had long enough was some stuff that looked like RG-8, but was labeled "Belden CB Coax". The braid coverage was less than 50 percent. Probably bought it because it was the cheapest stuff they had 40 years ago.

    I could just barely raise the repeater across town. The Bird meter showed 15 Watts at the back of the radio. Took the meter up to the roof and connected it at the base of the antenna. Showed just under a half Watt there.

    You gets what you pays for.

    On a good day.

    73
     

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