1. In celebration of the launch of the new redesigned site, we just gave away a FREE antenna! Click Here to See Who Won!

My coax debate

Discussion in 'General Ham Radio Discussion' started by avistar23, Feb 18, 2012.

  1. avistar23

    avistar23 Active Member

    Joined:
    May 17, 2005
    Messages:
    152
    Likes Received:
    17
    So i need some coax for my new antennas and amps

    ive used



    CNT 400
    LMR 400

    and im happy with both, runs will be 40 feet up the tower and 10 into shack, 50 total.

    i can get a good deal on 1/4 heliax, but it wont be able to make it into the radio as its too stiff, and would jumper a couple feet with LMR 400 or CNT

    ive also been looking at jefa tech coax

    what would you use, and why
     
    #1
  2. GnG8d

    GnG8d Well-Known Member

    Joined:
    Jun 28, 2010
    Messages:
    2,037
    Likes Received:
    316
    LMR400 .... because I have several hundred feet of it, it's low loss, and works to a 1" bend radius.
     
    #2
  3. W5LZ

    W5LZ Crotchety Old Bastard

    Joined:
    Apr 8, 2005
    Messages:
    6,834
    Likes Received:
    726
    Of the choices you gave I would have to say the LMR-400. But only if this is for VHF/UHF. If it's for HF, then all three of the choices are very much 'over-kill'. Even for VHF/UHF the heliax isn't exactly reasonable.
    - 'Doc
     
    #3
    2 people like this.
  4. Mudfoot

    Mudfoot Supporting Member

    Joined:
    Jun 17, 2009
    Messages:
    7,555
    Likes Received:
    2,217
    What he said.
     
    #4
  5. avistar23

    avistar23 Active Member

    Joined:
    May 17, 2005
    Messages:
    152
    Likes Received:
    17
    I have lmr on everything including my HF beam, i have 213 to my dipole, i like the LMR, but the 1/4 heliax although is quite small has nice loss figures
     
    #5
  6. Marconi

    Marconi Supporting Member

    Joined:
    Oct 23, 2005
    Messages:
    4,260
    Likes Received:
    293
    Aw go on and go for it 23, that heliax will really get you out. Just keep us posted on how it works out.
     
    #6
    1 person likes this.
  7. KingCobra_CDX882

    KingCobra_CDX882 W9WDX Amateur Radio Club Member

    Joined:
    Mar 30, 2005
    Messages:
    2,037
    Likes Received:
    42
    I use Heliax LDF5-50a HF and LDF7-50a VHF through SHF
     
    #7
    1 person likes this.
  8. mackmobile43

    mackmobile43 Jock Supporter

    Joined:
    Feb 11, 2008
    Messages:
    6,715
    Likes Received:
    362
    I have some *MPOWER coax if you're interested
     
    #8
  9. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    11,519
    Likes Received:
    2,902

    Yeah but you have more money than brains. :love::laugh: JK.......................well maybe.:whistle:
     
    #9
  10. avistar23

    avistar23 Active Member

    Joined:
    May 17, 2005
    Messages:
    152
    Likes Received:
    17
    Never heard of it?
     
    #10
  11. avistar23

    avistar23 Active Member

    Joined:
    May 17, 2005
    Messages:
    152
    Likes Received:
    17


    And yes those cables are far out my price range, and for a 50ft run on 144 i dont think i NEED such a low loss cable, want yes, need no.
     
    #11
  12. Captain Kilowatt

    Captain Kilowatt Professional Amateur Staff Member

    Joined:
    Apr 6, 2005
    Messages:
    11,519
    Likes Received:
    2,902

    Mack is just being Mack again.:blink:
     
    #12
  13. vo1ks

    vo1ks Active Member

    Joined:
    Feb 11, 2012
    Messages:
    276
    Likes Received:
    46
    In order to make a suggestion on cable type, more information is needed. Output power and frequency of operation would be the first things to look at.
    How flexible does it need to be? Will it be connected to a rotating antenna or expected to blow about in the wind?

    For a run of only 50 feet you won't worry much about attenuation.
     
    #13
  14. avistar23

    avistar23 Active Member

    Joined:
    May 17, 2005
    Messages:
    152
    Likes Received:
    17
    One run is for the larcan, Feeding ultimately a 6m7jhv or similar antenna, N connectors both ends, no rotation fixed antennas. hardline would make it within 6 feet of radio, where a flexible cable would be used, however i have devised a way i THINK i could feed the hardline threw the wall right into the back of my larcan cabinet.

    the second run, will go to my gulph alpha antenna i ordered in my 2m dx ssb thread, again, permanently fied facing south Florida, again this could make it into the wall within 6 feet of radio and go flexible, OR, if i decide to go with a second larcan amp as i emailed you earlier, i may again be able ot hardline into the cabinet IF i get a 2m amp.

    i can take lmr400 or similar cable right into the radio.

    N connector will be used wherever possible, also considering changing connectors on the back of my 847 to N
     
    #14
  15. vo1ks

    vo1ks Active Member

    Joined:
    Feb 11, 2012
    Messages:
    276
    Likes Received:
    46
    Attenuation on 50 feet of LMR400 is about 0.45dB @ 50MHz, 0.75dB @150MHz. LDF4 will be 0.22dB @ 50MHz and 0.40dB @150MHz.

    Once your signal leaves the antennna, if you find anyone that notices 0.2dB to 0.3dB signal difference he's spent too much money on test equipment. No one anywhere will ever tell the difference.

    Unless your power exceeds about 2.5kW @ 50MHz or 1.5kW @150MHz the LMR400 is entirely adequate. I wouldn't bother with the added hassle of dealing with LDF4 for what you're doing. Save your money for something else.

    Type-N connectors are considerably better than SO-239 / PL-259 connectors in every way I can think of. You can get an adapter for the back of your 847 to turn it into a Type-N. No need to open the radio. Remind me and I'll include an adapter with the other amplifier... :)
     
    #15

Share This Page