2 Meter J-Pole Grounding and Installation

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KK4HYS, May 20, 2012.

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  1. KK4HYS

    KK4HYS Ham Member QRZ Page

    Hi everyone,

    I'm a new ham and I just recently installed my KB9VBR 2Meter J-Pole. This is my first antenna ever and it has been very fun to install. It took me quite a bit of research and time before I could finally begin the installation so I thought I would share what I learned with others who may end up starting out their first antenna install.

    First, let me start out by saying that I live in Florida. Since Florida has a very high rate of lightning strikes, I decided grounding my antenna was a high priority for me. You can see in the image below Florida is the lightning capital of the U.S.


    As I began to research I came across several good free articles (PM me if you'd like a link) on what is required for proper grounding. The more complicated your set-up the more complicated your grounding (and costly) will be. Fortunately, all I needed was a simple Coax cable to run into my room since I am using a hand held tranciever (HT).

    Based on the design of my house and the location of the house grounds, I decided to mount the antenna to the side of the house for simplicity. Although, I would have preferred to mount it on the side of the 2nd story of my house for the extra height. This would've increased my expenses by requiring a lot more cable and would've made grounding the antenna more complicated. As a result, I went for a simple side house install. Fortunately, the mast is tall enough with the antenna attached to still reach above the 2nd story roof of my house. Its also far away enough to avoid any interference.

    I still haven't finished the install as I still have to drill a hole through the wall into my room to run the final coax cable but everything else is pretty much done.

    List of most (not all) Materials used:

    1. LMR-400 Cable
    Purchased 2 runs. 1 is 30 feet long and the other is 25 feet long. Both have PL259 connectors.
    I chose this cable since I will be running very low power (standard HT 5 watts) until eventually get an amp I wanted the least amount of loss. I also figure that the cable is just as important as the antenna. If I want to get a large distance (which I do) I can't be cheap on cable.

    2. KB9VBR 2Meter J-Pole

    3. Coax-Seal
    This is used to make sure no water/moisture enters the cable/feedpoint.

    4. Copper Plate
    The copper plate was used as the single point ground (SPG). My lightning arrester was attached to this. I ordered it from Grainger. Part# 2AAD1
    I would've ordered a smaller one (length wise) but they didnt have anything smaller. So I ended up cutting this (pictured below).

    5. Non-metal Electrical box
    Purchased this at Lowes. Cheap and easy to work with.

    6. Lightning arrester/surge protector
    I finally decided upon (after lots of research) the polyphaser IS-50UX-C0. Everyone should do research before purchasing one. Make sure it fits your application (freq wise). I'd also read reviews on any arrester before you buy it.

    7. Antenna Mast
    I purchased a 10ft aluminum pole from Lowes.

    8. 24" Clearance Y-Wall Mount
    These are the brackets that actually hold the antenna. They sell some on ebay but I found it a little cheaper after some searching.

    9. Ground cable
    20 feet of #4 THHN Cable from Lowes. I wish I could've gone with #2 but its too costly. Some people say that #6 will get the job done but bigger is almost always better.

    10. Metal Bracket
    The overhang at my house was 2 feet (24 inches) wide so my uncle and I had to fabricate some brackets to get an extra 2 inches of clearance since the largest Y-Wall mount was exactly 24inches. You'll see what I mean in the pictures below.

    11. Ground brackets.
    Bought these at lowes. One was mounted to the SPG and another to the actual antenna.

    12. Copper couplings

    13. Tapcon scews (to drill through concrete)

    14. Self-tapping screws

    15. Bolts, washers, and self-locking nuts.


    I forgot all the tools used. In truth, they were my uncles and he did most of the hands on work since he is 100x more handy than me. Some of the tools used were:

    1. Small electric saw
    2. 18v cordless Drill & bits
    3. High-powered corded drill.
    4. wrench/wratchet and socket
    5. Mapp Gas torch, soder, and Flux
    6. Screw driver


    The box used.


    The mast.


    The random bracket purchased to give us clearance.


    Flux being put on the antenna to soder the couplings on. My uncle says the the flux draws in the soder, giving you a better connection and more surface area sodered. Also clean the surface of the area before placing the flux by using an abrasive thing to remove any surface impurities (very important).


    Coupling being placed on. This will prevent the antenna from wiggling in the mast.


    Soder being placed on.


    Measuring. Marking where the self-tapping screws will go.



    Drilling them in.
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Is there a question in there, somewhere?:eek:

    BTW, the coax isn't just as important as the antenna. Not even close.

    On VHF, what makes antennas work is "height."

    Almost anyone with 45+ years experience on VHF as I have (and so do many) would agree the most important things on VHF are:

    1. Height above ground
    2. Height above ground
    3. Height above ground
    4. Antenna design
    5. Coax loss.

    1-3 are very important.:p
  3. KK4HYS

    KK4HYS Ham Member QRZ Page


    attaching the ground mount.



    All done.


    Added soder to the end of the ground cable. This will prevent the wire from spreading out when screwed in.


    Marking the bar to mount in the SPG box.


    Preping the box so the screws don't cause mounting problems. Also drilling the holes for the mounting.


    Everything attached to the SPG bar.


    Drilling holes for the coax cables to enter/leave.
  4. KK4HYS

    KK4HYS Ham Member QRZ Page


    The box mounted.


    Y-Wall Bracket Mounted along with the custom brackets to give me clearance.


    Antenna on the roof. You can see one of the towers with a repeater I like to hit in the background :)


    Coax Seal on the feedpoint to avoid moisture/rain.


    All done :cool:

    My appologies if I put too many pictures. I love pictures when I look up how to do things because it saves me from having to guess. Hope this post helps someone else out.
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Once you get some experience installing antennas I think you might realize all the weatherproofing on the coax connector isn't nearly as important as preventing water from getting into the connector via its receptacle (the female UHF connector mounted on the antenna itself) and I didn't see anything in the photos indicating that was handled.

    However, good job on making a coax loop just below that point: That should prevent water which intrudes from coming all the way down the coax and contaminating all of it. That's done well, and is really required of almost all outdoor antenna installations.
  6. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Great photos!

    Beware to expect significant corrosion due to dissimilar materials where your copper plumbers' delight is attached to the aluminum pole. Probably the easiest fix is to use a piece of doweling or broomstick to keep the two components separated.

  7. KK4HYS

    KK4HYS Ham Member QRZ Page

    I didn't realize I wasn't allowed to start a thread without a question. I assumed I was being helpful :)

    I understand what you're saying that the coax loss is not as important as the antenna, but I disagree. If you are using a HT (as I am) with only 5 watts of power and have long runs of cable, the coax can be JUST (if not more so) as important as the antenna.

    I do agree that the height of the antenna is more important than either the coax and antenna.
  8. KK4HYS

    KK4HYS Ham Member QRZ Page

    On the famale, are you reffering to the back of it? Or the side where the PL259 connector actually connects. You're correct about the back side, I didn't think I had to cover that side too. Should I go ahead and cover it with coax seal?

    The loop at the top is a balun loop to prevent the RF going down and yes it was also done with the intention of preventing water from coming all the way down, JIC.

    Thanks! What about painting them? Would that do the trick?
  9. KB4QAA

    KB4QAA XML Subscriber QRZ Page

    Yeah, painting would probably work.
  10. K9SAT

    K9SAT Ham Member QRZ Page

    I have this same type of installation for my Jpole for local 2m repeaters ant it works well.
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