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Running Radials the Easy Way - Sew What?

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by KJ5XX, Oct 30, 2009.

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  1. KJ5XX

    KJ5XX Ham Member QRZ Page

    In the process of building a stealthy vertical antenna system recently, I was thinking about how best to install an efficient radial system on my city-sized lot.

    It occurred to me that other than not wanting to run over the radials with the lawnmower, that there really wasn't a real need to "bury" the radials at all.

    I came up with the idea of "sewing" the radials just below the surface of the grass. The next question was finding a suitable sewing needle that was up to the task.

    The solution I came up with was to use a stainless steel whip from an old Bugcatcher antenna that I was no longer using. The whip was about 4' in length and provided a nice flexible, yet thin and sturdy platform that turned out to be just perfect for threading my radial system.

    Of course a longer whip would be even better, and would prevent having to pull the needle through and reinsert it again.

    To use this method, I did the following:


    1. Cut your radials. My antenna was designed to operate on 40, 20, 15 and 10 meters, so I cut sets of radials for each of these bands. It helps to have one wire color for each band you plan to operate on. This isn't a requirement, but makes running the wires easier as we'll see in a moment, if you plan on laying your radials in "sets".

    2. Using "marking paint" (found in local hardware stores in bright orange or red, but any can of spray in a color that is easily seen will work), I marked the distance from my antenna to the place in the grass that each length of radial would terminate at, so measuring out from the radial, I made spray marks in my lawn at the termination point for a 40m, 20m, 15m, and 10m radials, and I repeated this process for each "set" of radials that I ran.

    3. Drive a stake in the ground at the point where your radial system will attach to your antenna base. Leave an inch or so extra on the end of each radial to be sure that you have what you need for your solder lugs or whatever you are planning to use to attach the radials to the base of your antenna.

    4. Using electrical tape (duct tape will also work well), tape the other end of your radial set to your needle. There is no need to wrap multiple layers of tape. Just tape the radials to your needle so that they are secure, but not too tight.

    5. Keeping the needle parallel to your lawn and close to the surface, thread the tip of the needle just beneath the surface of the grass. You'll be able to feel when you are going too deep - just pull the needle back out an inch or so and re-thread. You'll also be able to "see" your needle as it makes progress, as it will cause the grass to sort of push up as it tunnels its way through. If you run out of "needle" before you reach your spraypaint mark, feel along the needle until you reach the tip, then just keep pushing it along, under the surface - no need to pull it out and start threading again, you should be able to keep feeding it even though the entire needle is under the surface of the grass.

    6. When you approach your first spraypaint mark, push the end of the needle up close to that mark, then feel for the needle and extract the end. If you measured correctly, your shortest radial should be taught and line up with your paint mark.

    7. Having identified your shortest radial, pull it free from the needle. If you used a different colored wire for each band, this will be very easy to identify.

    8. Now, take the portion of the radial you just pulled free from the needle and push it underneath your grass. If you need to, you can use a box cutter to make a slit in the grass and re-insert the radial end.

    9. Keep on pushing the needle through, just under the surface. Repeat this process until you have all of your radials laid.

    As an alternative, you can lay the radials one at a time as opposed to laying them in sets. You may find this faster depending on what bands you plan on using (and therefore, how close the radials are in length to one another - this is kind of hard to explain, but if the lengths are close and you lay them in sets, it can make it hard to extract the needle and re-insert it).

    That's it!

    I'd be interested in hearing from other hams that have tried this method, and have any suggestions for improving it (or the instructions I've laid out here).

    73,
     
    Last edited: Nov 2, 2009
  2. WB3BEL

    WB3BEL Ham Member QRZ Page

    It sounds like you have run your radials for the different bands essentially right alongside each other.

    If this is true, then its rather inefficient. Radials that are laying on the ground are not really resonant. You could have gotten away with a single one for the lowest frequency per "set".

    What I would recommend is to just run as many as possible for the lowest frequency band fanned out around the base of the vertical. Maybe 60 radials each about 25 feet long would be good for 40m. You can do fewer if you are short of cash or wire. Or more if you are inclined and want a bit better performance depending on your soil conductivity. This set will work fine for all the other bands as well.

    Oh and by the way. You are right. You don't need to bury the radials. Mow the grass short in the fall. Lay the radials on the ground and stake them down with lawn staples or cut up section of steel coat hangers. When the spring comes and its time for the mower, They will already be gone...Even less work than your method.
     
  3. KJ5XX

    KJ5XX Ham Member QRZ Page

    Great suggestions on both counts.

    I thought about the idea of staking them down with coat hangers or something similar, but haven't tried it - I like it! Not sure what a lawn staple is though.

    Thanks - great suggestions - no one will ever accuse us hams of not being innovative!!:D
     
  4. VE3PP

    VE3PP XML Subscriber QRZ Page

    Go to any lumber, hardware or farm supply store and you can buy U shaped nails. Used for fencing, and they will work just fine for holding those radials down until the thatch gets over top them.

    The only issue with leaving radials on top the lawn is this. If you aerate your lawn like I do the tines on the machine can cut the radials.

    If you do not do that then you'll have no problems laying them on top of the lawn and stapling them down.

    I was also told by an RF engineer that cutting radials for each band was a waste of time. He told me, ( he has done extensive testing on this) that you are better off laying down 50-60 radials cut the same length as the vertical you are putting up.

    So if your 4 band vertical is 21 feet in height he suggested laying down radials that are 21 feet in length.
     
    Last edited: Oct 31, 2009
  5. R3BU

    R3BU Ham Member QRZ Page

    As for radials, as it looks from the distance in your part of the world people use mainly buried or lying on the ground NON-rezonant radials.Minimal loses start from 50 or even 100 peaces applyed. Similar low loses in the ground system coud be acheved with only two or four REZONANT 0.25wl radials, but situated at hights starting from 0.15wl and higher under the ground.Here we more often use the second method.Even having -this is my experience-two 0.25wl radials at only 2 m hight, My shortend GP on 3.8mhz works pretty well.
     
    Last edited: Oct 31, 2009
  6. KB9MZ

    KB9MZ Ham Member QRZ Page

    I you have a wheel barrow add a steel disk to the front wheel shaft with disk a larger diameter than the wheel such that the wheel controls the depth.
    Quick and easy with no damage with respect to appearance. Put the child in the barrow and make him happy as well at the same time !
     
  7. K7NNO

    K7NNO Moderator QRZ Page

    What you are describing is a counterpoise. But in his case he cant have them seen so he has to bury them.
     
  8. KJ5XX

    KJ5XX Ham Member QRZ Page

    Ha! Love it! If I put my wife in the wheelbarrow, would I be able to lay them even deeper? (I didn't just say that did I?)

    Great idea - dang, you guys are making my idea look dumber all the time! :D
     
  9. WA4LZC

    WA4LZC Subscriber QRZ Page

    ######I was also told by an RF engineer that cutting radials for each band was a waste of time. He told me, ( he has done extensive testing on this) that you are better off laying down 50-60 radials cut the same length as the vertical you are putting up.

    So if your 4 band vertical is 21 feet in height he suggested laying down radials that are 21 feet in length. ########

    Would that work for an screwdriver antenna like a Tarheel 300A mounted on a 10 foot mast which puts the base of the antenna about a foot off the roof?
    I was going to fan the radials out across the roof of my house.
     
  10. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Not nearly as well. For an elevated vertical, it's best to make them resonant for each band, and use as many as you can to keep the current in the radials very low (and thus having less loss). The radials for such a "short" vertical will all be longer than the antenna itself.
     
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