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Author Topic: Winding up wire for portable antenna  (Read 3228 times)
K7RNO
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Posts: 279




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« on: July 20, 2013, 08:38:51 PM »

So I finished a 40' ground plane with four radials (2x17' and 2x33'), all #14 AWG stranded copper and all soldered together at the PL-239. This will be for portable use in the park.

To store it, I wound it up, beginning with the radial ends, on a wooden rig in the shape of a wide U, like this:  |___|
The wires are being wound in a figure-8 pattern around the two vertical parts of this U, preventing kinks. Works quite well, and I hope undoing it will be similarly easy, ending up with a sorted array of five wires without entanglement and kinks. One can dream, no?

Is there a different, better way to do this? Are there some tricks and tips on how to keep the wires separate when unwinding? What would a tutorial on winding such a ground plane look like?
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73,
aRNO
NAQCC #6870, SKCC #11131
G4AON
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Posts: 543




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« Reply #1 on: July 21, 2013, 03:44:24 AM »

An alternative method of dealing with portable antenna radials is described here:

http://www.dh1tw.de/how-to-rapidly-deploy-remove-radials

73 Dave
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AC4RD
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Posts: 1235




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« Reply #2 on: July 21, 2013, 04:58:31 AM »

I often wind them up individually on small forms that can be anything I have to hand at the time--an old CD case, cheap plastic water tumblers, old solder spools, etc.  I find that it helps if, as I'm rolling the radials onto the form, I rotate the form and not wind the wire around it, if you see what I mean.  Simple binder clips hold the end of the wire. 

And I'll tell you the truth: I'll be watching this thread to see better ideas, because the way I've been doing it is still clumsy and avoiding kinks isn't easy.  :-)  So I'm hoping to learn something from the replies to this thread.  Wink
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KC7YE
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Posts: 101




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« Reply #3 on: July 21, 2013, 06:30:02 AM »

I use kite string / handle for radial & antenna wire. Works OK with the smaller lighter wire, THHN 14, not so good. Kite shop but Buddiploe is cheapest.
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K5LXP
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Posts: 4522


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« Reply #4 on: July 21, 2013, 02:12:46 PM »

So I finished a 40' ground plane with four radials (2x17' and 2x33'), all #14 AWG stranded copper and all soldered together at the PL-239. This will be for portable use in the park.

Are these radials elevated?

Quote
Is there a different, better way to do this?

Not sure about "better" but for my portable vertical, which is a crappie pole supporting a wire element and ground radials, I use 16, 16 foot long radials.  Four radials are crimped to a single ring lug, so there's four sets of four radials.  I wind each set of four radials onto a spool sequentially, starting with the end opposite the lugs.  So when it's time to deploy, a lug is placed at the feedpoint and the spool unrolled to the next lug.  Back to the feedpoint, rotate 90 degrees and repeat for all the sets.  With the lugs attached at the feedpoint I then walk out each radial from the bundle into a spoke pattern.

Maybe this could be a adapted for your setup.

Mark K5LXP
Albuquerque, NM
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K7RNO
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Posts: 279




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« Reply #5 on: July 21, 2013, 04:27:09 PM »

Today I got to try out my new vertical ground planeā€”and how the unwinding and winding back up worked.

I have to say that my wooden "spool" contraption worked well. I unwound/set up the antenna in the following steps:

1. After the pulling line was shot up into the tree and ready to deploy, I unwound the wires, beginning with the radiator. Once I had enough length unwound, I connected the tip of it (I had crimped on an eye terminal) to the line in the tree, then unwound more of the radiator, slowly walking to lay it out on the ground.

2. Once I reached the UHF connector, where everything was soldered together, I started pulling up the radiator until that was completely in the air with the connector at chest level, when I attached the coax.

3. Now I continued unwinding the radials and raising them until I reached the point where my (15') coax would still be able to reach the TRX. I then tied off the line holding the antenna up.

4. At that point I separated the four radials into their pattern and then unwound the rest of the two long radials.

5. Finding a spot where to stretch out and then tie up the elevated radials was next, after which the antenna was ready to transmit (which it did very well).

6. To wind it back up, I got all the radials loose again, still laid out in their directions on the ground. Then I lowered the antenna to a point where I could reach the UHF connector.

7. Disconnect the coax

8. Very important: "Comb" the four radials through the fingers of my left hand, while running down on them to bundle them, all being the same length and parallel, not twisted. Once I reached the end of the shorter radials, I tied all four together at that point and continued to comb the two longer ones till I reached their end.

9. Back onto the wooden "spool", beginning with the two longest radials, winding them in figure-8 pattern to not get any kinks. Continuing past the tied-up point where the shorter radials started, to the UHF connector and the radiator and than to its end.

10. Once all was wound up, I tied the bunch together at both ends of the "spool" near the two wooden legs over which they were wound, to prevent anything from coming loose.

Done, and ready for the next deployment.

So, Mark, you had found your answer regarding the radials being elevated. Probably some 12 feet up, sloping a bit from there.
Since my wires are all soldered together (a mistake?), I can't use your procedure. Thank you for sharing it, though, somebody might find it very helpful.

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73,
aRNO
NAQCC #6870, SKCC #11131
WB6BYU
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Posts: 13481




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« Reply #6 on: July 21, 2013, 09:57:56 PM »

All my wires and ropes (and anything else that needs winding) are all done the same way -
in a figure-of-8 across my palm (thumb to little finger), forearm (thumb to elbow), or, for
large climbing ropes, across my knees as far apart as I can spread them while sitting down
with the soles of my feet together.

The reason for this is that winding in a figure-of-8 does not impart any twist to the rope/wire,
which simply wrapping it around a single object does.  It also makes tangles much less likely
(and easier to remove when they do occur) because each layer crosses over the layer below
it.  Because you aren't twisting the wire as you wind it, kinks are much less of a problem.

How well does it work?  I can wind up 50' of rope on my hand (thumb to little finger, making
sure each turn crosses the others across my palm), fold it over itself, stuff it in a pocket,
then pull one end and it all comes out without tangles.  (The secret is to start pulling from
the end where you started winding.)  I've taken a 200' roll of rope that has been wound up
in a tub of rope for several years, tied one end to the top of a 100' tower, and tossed the
remainder off into space.  There was one small tangle that came right out when the folks
on the ground gave it a little tug.

My first portable dipole kit used magnet wire wound around a cardboard tube - that lasted
for one trip, only because I couldn't change it out in the middle of the wilderness.  By the
second trip I was using stranded, insulated wire (#22 to #26 or so) and winding the wire
across my palm - saves a lot of time.

Once you have most of the wire wound, wrap it several times around the center of the
bundle, form a bight, pass the bight through the hole in one end (where your fingers were)
and over the top of the winding, then pull the free end to tighten it.  This even allows
you to attach the free end of the wire to the center insulator / rope / or whatever BEFORE
unwinding it, because you never passed the end itself through anything.

If you don't like doing it on your hand, you can use  flat board with a notch cut out of
each end and wind it on each side of the board (convenient for the two halves of a
dipole, for example.)


I keep all my wires separate, with the center insulator permanently connected to one end
of the coax.  That allows me to connect any set of antenna wires I want each time I set
it up, and I can use the various dipole wires in lots of different configurations.  For example,
one 40m dipole wire can be used as a full wave loop on 10m (add an 18" clip lead for SSB,
two for CW.)  I add either the 10m or 15m wires to the ends of my 80m dipole to switch
it between SSB and CW.  (I've even used the 40m and 80m wires together to make a parallel
conductor feedline for a 20m doublet hanging over a cliff.)

Makes my life simple, and I spend a lot less time untangling wires and ropes.  That gives me
more time for operating.
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K7RNO
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Posts: 279




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« Reply #7 on: July 22, 2013, 07:37:13 PM »

That is great, Dale, and you knew I would come back with more questions, right?

So, I am planning to keep the 40' ladder line detachable from the dipole's center insulator (thank you for that tip). How do I wind up that (450 ohm) ladder line? The figure-8 pattern doesn't seem to be easy because of the line's width. Do I have to roll that up hand-over-hand? Or can I do it over the knees, like your climbing ropes?

And then the 70' coax (it will be RG8X). That one could go over the knees, I guess?
Can I leave the unneeded portion of that coax wound up in a bunch lying on the ground when transmitting? Or how should I lay it out?

Also, do I need to consider the height at the insulator and the connector plugs as part of the ladder line to determine the full length of that feed line? Or am I over-analyzing this too?
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73,
aRNO
NAQCC #6870, SKCC #11131
WB6BYU
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Posts: 13481




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« Reply #8 on: July 22, 2013, 09:17:05 PM »

Quote from: K7RNO

That is great, Dale, and you knew I would come back with more questions, right?




And you knew that my response would send you in even more directions, right?



Quote

So, I am planning to keep the 40' ladder line detachable from the dipole's center insulator (thank you for that tip). How do I wind up that (450 ohm) ladder line? The figure-8 pattern doesn't seem to be easy because of the line's width. Do I have to roll that up hand-over-hand? Or can I do it over the knees, like your climbing ropes?



To answer your question, yes, it winds up in a figure 8 also.  I'd probably do it over my palm and
elbow, depending on how big of a bundle it makes.  This is where the figure-8 method really shines,
because you can keep the twinlead flat without twisting or kinking.  (I originally learned the method
using flat fiberglass survey chains, then we used it for teletype tapes in early computer days.)

Knees is only for the biggest stuff, and since one wrap takes more than 5 feet of line there wouldn't
be much to the coil anyway.


But then I have to ask, WHY LADDER LINE???  Or more precisely, WHY THE COMBINATION OF
LADDER LINE AND COAX???  This approach can be useful when the wire and feedline lengths are
carefully chosen to provide a convenient feedpoint impedance (such as a G5RV / ZS6BKW) but
generally is is NOT a good idea otherwise.

Let me give you an example:  I created a quick model of a 40' vertical wire with sloping radials
(2 each) of 16.5' and 33'.  This is in free space, no ground, but it should give a rough idea of the
issues.  The modeled SWR at 7.2 MHz at the feedpoint is 9 : 1 at 7.2 MHz and 65 : 1 at 14.2 MHz.

If I add 40' of 450 ohm line in series then the SWR rises to 38 : 1 on 40m and down to 24 : 1 on 20m.
The loss in the coax on both bands is now about 70% (5dB).  That is, about 30% of your power
reaches the antenna.  By contrast, if you could feed the antenna directly with 70' of RG-8x on
40m you'd get twice the radiated power.  (It does lower the losses on 20m, however, as otherwise
it would be about 8dB, or 15% of your power reaching the antenna.)

Note:  I didn't model the velocity factor of the 450 ohm twinlead.  But the losses in the coax will
vary significantly with the length of the ladder line.

Now, that doesn't mean you won't make contacts, but you'll just have to work harder at it.


When I recommended the 40' wire I was thinking it would plug right into the antenna tuner in
the back of the radio, avoiding the losses in the feedline.  Then you can run the radials out
horizontally from that point.  If you want to use coax feed then use a 1/4 wave wire (about
33' for the vertical on 40m, and either a parallel quarter wave wire, a trap, or some other
method of matching it on 20m.  That will improve your signal and allow you to make more
contacts on the same battery power.




Quote

And then the 70' coax (it will be RG8X). That one could go over the knees, I guess?



No, that should work along the forearm as well.  And, yes, you can leave the unused
portion coiled up.
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K7RNO
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Posts: 279




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« Reply #9 on: July 22, 2013, 10:23:23 PM »

New direction, indeed, Dale  Wink

My fault, maybe, if I wasn't clear enough. The ladder/coax combination is not meant for the 40' vertical but for the
ZS6BKW dipole, for which he figures about 40' of ladder line. That wouldn't reach my tuner, if I can get it up high enough, so I would have to add coax. If you remember, that was one of my ingoing questions in that other thread.

Why 70' of coax? I stole that idea from one of the commercial sellers of that dipole, who stresses the point that it needs 70' after the ladder line. Why, I don't know, but I hope they know better than I (and they are not selling the coax).

Regarding the winding, palm & elbow sound like a plan (I learned the figure-8 method in the navy, where I also learned Morse code).

The other suggestions you make regarding the vertical, I will have to read again tomorrow when I'm more awake. When I used that antenna a couple of days ago, I connected with a 15' RG58.

GN & 73,
Arno
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73,
aRNO
NAQCC #6870, SKCC #11131
K9PAC
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Posts: 3




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« Reply #10 on: July 23, 2013, 07:06:42 AM »

I'm a stagehand and stick to the tried and true "over/under."  I'm sure there are UTUBE vids showing it better than I can explain it.

Also, if one end of a line (or cable or wire) is captured, begin winding at the captured end so the free end can flip/flop and not put twists into the line.

Just the way I was taught and has always worked.

73

K9PAC
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Be the change you want to see...begin at work.
WB6BYU
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Posts: 13481




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« Reply #11 on: July 23, 2013, 08:51:32 AM »

"Over/under" is particularly good for larger coax, like RG-213, though can be applied to
other sizes as well.  I'm now using it more for coax since I have to store them in a hot
attic, because making a large circle doesn't bend the cable as sharply as the figure-8
method.  (Sharp bends can cause the center conductor to migrate through a foam
inner insulation when it gets hot.)  It does have the same advantage that it doesn't
twist the cable, though it isn't quite as good for grabbing one end and pulling it out
without tangling.
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