True Ladder Line 10-80 Antenna with Balun/tuner?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KB1QYH, Dec 31, 2018.

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  1. WQ2H

    WQ2H QRZ Lifetime Member #214 Platinum Subscriber Life Member QRZ Page

    I've got the 80-10x150, and I love it. It's a great Rx antenna - one of the quietest I have, even during really bad NH weather.
    It even hears 136kHz pretty well too. I tune it with a straight AT2K.
    Good luck !
    73
    Jim, WQ2H


     
  2. KB1QYH

    KB1QYH XML Subscriber QRZ Page

    Hey Everyone! Thank you for the comments, but I'm thinking of going in a different direction now. I'm thinking get rid of the balun entirely, and buy a Palstar BT1500a tuner. To get the 600 ohm ladder line into the house I was thinking of buying two 1/4 20 stainless steel threaded rods, placed inside a PVC pipe. Pack the PVC pipe with Caulk (Alex Fast-Dry) and once that sets, drill two holes through the side of my brand new house and set them in with more caulk. What does everyone think of this? This way it will be easy to disconnect when I'm not operating. I can just go outside and disconnect the two wires and short to ground. Thoughts?!
     
  3. W5DXP

    W5DXP Ham Member QRZ Page

    I use two side-by-side pieces of RG-213 to get my ladder line inside the window (or you could use parallel coax barrel connectors). With the high SWR (usually) on the ladder line, I don't even notice the impedance bump. Parallel runs of RG-213 have a Z0 of 100 ohms. The shields are tied together and run to system ground.
     
    K7TRF likes this.
  4. KB1QYH

    KB1QYH XML Subscriber QRZ Page

    What do you mean the shields run to ground? What does that have to do with anything? You are still bringing in un-grounded "hot" wire into the shack. Can you explain, and/or send a pic? How do you disconnect it when you are done operating?

     
  5. N1JYU

    N1JYU Ham Member QRZ Page

    Hi Brian,
    When you feed directly to the balanced terminals of the MFJ-993B, are you connecting the ladder line to them or is this using coax to a balan that the ladder line is connected to?

    Russ N1JYU

     
  6. WB2JIX

    WB2JIX Ham Member QRZ Page

    I have used both methods however, I always prefer direct and no balun.
    Brian
     
  7. K4EI

    K4EI XML Subscriber QRZ Page

    A direct connection of ladder line to the balanced terminals of a tuner inside the shack also provides a direct route for lightning to the inside of your house. Is that not a concern?
     
  8. WB2JIX

    WB2JIX Ham Member QRZ Page

    Most everyone I know, me included, keeps their feedline grounded (coax as well) or, disconnected and we don't operate in lightning storms.
    There are many aspects of this hobby where a bit of common sense is called for.
     
  9. WR2E

    WR2E Ham Member QRZ Page

    Is that somehow different than coax cable?
     
  10. K4EI

    K4EI XML Subscriber QRZ Page

    Well, no, I'm not talking about operating during lightning storms. And "grounding your feedline" can mean different things, depending upon your architecture. Disconnecting your antenna and tossing it outside on the ground can work, of course. If you do it.

    I posed the question not to be snarky, but out of genuine curiosity at how folks are approaching the use of ladder line. My two current HF antennas are coax-fed... terminating first at gas-tube lightning arrestors mounted on a ground rod outside my shack, thence routed through the window pass-through to separately-grounded coax switches inside the shack.

    My next antenna will be a full-wave 160-meter horizontal loop, fed with 450-ohm ladder line. I have a Palstar manual tuner which includes a balanced line connection (and associated internal 4:1 balun)... and so the easiest connection would simply be a direct termination to the back of that tuner (my window pass-through also has a balanced line connection, so no problem getting it inside).

    In wrestling with the question of high inducted currents from nearby lightning, though - particularly since a 160-meter loop is a LOT of wire - I decided against that approach. I've decided to terminate my ladder line at a 4:1 balun mounted outside my shack, then run a short coax jumper to a lightning arrestor, and thence into the shack exactly like my current antennas.

    The other alternative I considered was making or buying a lightning arrestor specifically for ladder line (like https://www.arraysolutions.com/as-309h). I might try that approach somewhere down the road.

    Not making any judgments on folks who do it differently. Just wondering about the thought process behind it.
     

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