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eHam Forums => HomeBrew => Topic started by: AE7TE on November 23, 2017, 08:58:17 PM



Title: Ladder line using popsicle sticks
Post by: AE7TE on November 23, 2017, 08:58:17 PM
I'm about to try something absolutely crazy.

I just cut 25 popsicle sticks up into pieces 2 inches (50mm) long. I'm going to make holes in them which will friction-fit onto insulated wire. I'm not sure what wire I want to use yet, but it will likely be wire with soft, pliable insulation like speaker wire.

Once that happens, I'm going to dunk them all into a bath of melted wax so they are sealed. I can melt a big pot of wax and dunk them all at once. Then, I'll string them onto wire to make a 25 foot run of ladder line. The result will be a roll that will be easily usable in the field, with a QRP radio. The feed line is going to be extremely low-loss and work with a doublet to force as much of a 5w signal into the air.

I'm also sure these won't last forever. The wood is not excellent quality (for the price of a bag of popsicle sticks, I'm not expecting much). This is an experiment to see how long they work, as well as how well the twin-lead performs.

Ed AE7TE


Title: RE: Ladder line using popsicle sticks
Post by: WB6BYU on November 23, 2017, 10:28:11 PM
One issue will be threading the wire through that many spreaders with a snug fit in each hole.

A better way is to use a short length of wire (or small cable tie, etc.) to pass through a hold in the end
of the stick and around the feedline wire - that saves a lot of construction work.

Sometimes a thin bare wire is passed through holes in the spreader and wrapped around (possibly
soldered) to the main wire on each side.  This could also be insulated wire if it isn't going to be soldered.
You should be able to wrap it tightly enough to hold the spreaders in place.  Basically, the main feedline
wire passes beside the spreader and a short piece of wire holds them in place.


In the end, I don't know that this approach will actually deliver significantly more RF to the antenna than
using TV twinlead, or some of the other options.  The ARRL has only recently admitted that their "standard"
formulas and charts for the loss of open wire line have been in error for many years.  (It looks llike someone
only included the resistance of one of the two wires in the calculation.)  As a result, open wire lines, while
having low losses, really aren't as low loss as some articles have made them out to be.   300 ohm twinlead
may be a worthwhile trade-off by saving the time of making your own, and by the time you include the
potential losses in a balanced tuner, you might not gain that much over just using coax, which is simpler.
(The losses in 25' of feedline is pretty low, especially on the lower bands.  I use 25' of RG-174 for my
backpack dipole kit, and the worst case loss on 10m is just over 1 dB, and less on the lower frequencies.
By eliminating the antenna tuner I can make up part of this loss, so open wire line really doesn't make
much of an improvement.


But if you want to try it, one of the antennas I made used a combination spreader / center insulator along
with a pair of 65' wires:  by moving the spreader / center insulator along the pair of wires, I can very the
length of the doublet vs. the feedline length.  The spacing at the center is about 6", and I use a second spreader
at the feed end.  In use, I adjust to the dipole length I want to use, tie off the wires on the spreader/insulator,
and use the rest of the wires for the feedline.  By putting some tension on the wire I can (hopefully) keep the
wires spread sufficiently without needing extra spreaders.  Actually the antenna has been sitting in my box
of antennas to try for perhaps 15 years now - I just haven't had an opportunity that called for it.  One of these days...


Title: RE: Ladder line using popsicle sticks
Post by: KF4ZGZ on November 24, 2017, 02:52:35 AM
I would cut notches or slots in the ends just big enough for a snug slip fit ...... add a touch of hot glue or even dollar store superglue.
Pulling the wire through a friction fit hole won't be fun.
As for wire .... I would use 14ga. stranded house wire.
And if it was me, I would have went with 6", but you should be ok.


Matt


Title: RE: Ladder line using popsicle sticks
Post by: LA9XNA on November 24, 2017, 03:04:22 AM
Use hotglue to fix the wire to the spreader.
A smal dot on each side of the spreader and your good.


Title: RE: Ladder line using popsicle sticks
Post by: W6EM on November 24, 2017, 10:39:16 AM
While popsicle sticks are cheap, there are some materials that can be used that may not be quite as cheap, but fare far better outside.

For one thing, parrafin wax begins to melt at 99F, which on a hot summer day willmelt it off/out of the wood.  And, wood will wick up moisture from humid air and rain.  Commercial VHF collinear antenna manufacturers use beeswax to hold the elements vertically, inside fiberglass tubing as beeswax melts at a much higher temperature. 

Here's a link that will allow you to calculate the characteristic impedance of what you construct, and has a really good suggestion for cheap ladder insulators.  Black polyethylene irrigation tubing.  It is sold in coils at most hardware/landscape suppliers.  Using black zip ties to hold the wire against the short pieces of cut tubing also is a good way to anchor the wires to the short pieces.

If you still want to use the wood, soak and coat them thoroughly with black epoxy marine paint.  Much better in humid environs.

73.

Lee



Title: RE: Ladder line using popsicle sticks
Post by: W6EM on November 24, 2017, 03:49:46 PM
Oops, I left out the link......

http://hamwaves.com/zc.circular/en/index.html



Title: RE: Ladder line using popsicle sticks
Post by: K8AXW on November 24, 2017, 06:47:42 PM
If I was going to go to all of that  trouble I'd follow the previous hints, (Pick one) but I would also soak the sticks in melted (some have said boiling - be careful of burns and it lighting off!)  paraffin to make it weatherproof. 

This is what many old times did for their 600 ohm ladder line.


Title: RE: Ladder line using popsicle sticks
Post by: N7EKU on November 24, 2017, 07:30:28 PM
Hi Ed,

Since the wire will have the same insulation whether it is zipped together as it comes, or separated by the sticks, the loss won't be any different I think.  Just the impedance of the line will change.  Zipped it will probably be something like 100 ohms and with 1" sticks maybe 300 ohms.  Of course the loss would change if the line was wet though as the wet lines together would cause changes in impedance and increased losses.
 Probably RG-174 would give the same or less loss if running a halfwave dipole antenna.

I would just choose this sticks method if you specifically needed a certain higher line impedance or if you were considering to operate with wet lines.  I think the wax would make the sticks last as long as the wire would since you are just operating portable.  Sure hot sun may melt the wax, but it wouldn't suddenly cause it to separate itself from the wood.  The fibers and pores of the wood would tend to hold the wax well I think.  Of course you could use candle wax or beeswax too.  Tung oil or linseed oil would probably work well too.

Good luck and have fun :-)


Mark.


I'm about to try something absolutely crazy.

I just cut 25 popsicle sticks up into pieces 2 inches (50mm) long. I'm going to make holes in them which will friction-fit onto insulated wire. I'm not sure what wire I want to use yet, but it will likely be wire with soft, pliable insulation like speaker wire.

Once that happens, I'm going to dunk them all into a bath of melted wax so they are sealed. I can melt a big pot of wax and dunk them all at once. Then, I'll string them onto wire to make a 25 foot run of ladder line. The result will be a roll that will be easily usable in the field, with a QRP radio. The feed line is going to be extremely low-loss and work with a doublet to force as much of a 5w signal into the air.

I'm also sure these won't last forever. The wood is not excellent quality (for the price of a bag of popsicle sticks, I'm not expecting much). This is an experiment to see how long they work, as well as how well the twin-lead performs.

Ed AE7TE



Title: RE: Ladder line using popsicle sticks
Post by: ZENKI on November 24, 2017, 08:24:56 PM
Find an electronics manufacturer or PCB maker near your location.

When people get PCB boards made they come in panels that are broken apart after parts placement. These are fiberglass or G10 epoxy boards with an excellent mask coating.

These remains are like popsicle sticks but will  see you into the grave. Another good thing about them is that they are light, UV and waterproof. I have not found a better spreader yet.

I'm about to try something absolutely crazy.

I just cut 25 popsicle sticks up into pieces 2 inches (50mm) long. I'm going to make holes in them which will friction-fit onto insulated wire. I'm not sure what wire I want to use yet, but it will likely be wire with soft, pliable insulation like speaker wire.

Once that happens, I'm going to dunk them all into a bath of melted wax so they are sealed. I can melt a big pot of wax and dunk them all at once. Then, I'll string them onto wire to make a 25 foot run of ladder line. The result will be a roll that will be easily usable in the field, with a QRP radio. The feed line is going to be extremely low-loss and work with a doublet to force as much of a 5w signal into the air.

I'm also sure these won't last forever. The wood is not excellent quality (for the price of a bag of popsicle sticks, I'm not expecting much). This is an experiment to see how long they work, as well as how well the twin-lead performs.

Ed AE7TE


Title: RE: Ladder line using popsicle sticks
Post by: AE7TE on November 25, 2017, 12:03:38 AM
I tried painting them all with rustoleum oil based paint. Because the paint is old and takes days for full drying, I said to hell with it and dumped all of the separators in the garbage.

I have a big spool of TV 300 ohm line I got from a second hand store. I think I'll use that instead. I normally prefer to roll my own but this time it was a bit ridiculous. The only reason to even attempt what I was doing was because popsicle sticks are so ridiculously cheap.

I have made my own twin lead before, by cutting up coat hangers and using the plastic. It's very time consuming and I can't comment on how worthwhile it is.

Ed


Title: RE: Ladder line using popsicle sticks
Post by: G3RZP on November 25, 2017, 02:35:01 AM
I tried all sorts of plastic spreaders, and they all eventually succumbed to UV even in the relatively low UV environment in the UK. $30 in the Dayton fleamarket got me a box of about 2 inch long 3/8 inch diameter ceramic insulators as used on USN aircraft in WW2 - I saw exactly the same insulators on an aircraft in the USAF museum. With 16SWG (14 AWG) hard drawn copper wires and about 60 feet long, the open wire line has lasted over 20 years.


Title: RE: Ladder line using popsicle sticks
Post by: KU3X on November 25, 2017, 04:24:54 AM
Very creative. Sounds like a fun project.
I needed to use 540 ohm parallel feeders to feed a double extended zepp, for a matching section. 450 ohms was too low and 600 ohms was too high, so I built my own. I used one half inch PVC. I drilled holes and fed the wire through the holes. The hole size was just a tad bigger than the OD of the wire. To keep the spreaders in place, I used a pair of needle nose plyers, stuck the plyers in each end of the PVC and gave the wire a tiny twist. Just a few degrees is all that is needed. No way could you move the PVC once the wires had the twist in it.
That antenna is still in service today.

Barry
www.ku3x.net
                  


Title: RE: Ladder line using popsicle sticks
Post by: WB6BYU on November 25, 2017, 07:17:20 AM
Quote from: N7EKU

Since the wire will have the same insulation whether it is zipped together as it comes, or separated by the sticks, the loss won't be any different I think...



Actually it does make a difference:  that is one reason they put windows in
windowed twinlead.



The loss depends on how much of the field passes through the lossy PVC dialectic.
An air gap greatly reduces the losses.  Think of the dielectric as a resistor:
adding a larger resistor (air) in series with the resistances of the insulation
layers reduces the total leakage currents.  That's a simplification, but it
explains why the air gap is significant.

The PVC used in most wire insulation is much lossier than the polyethylene used
in transmission lines.  While dielectric losses are usually insignificant in a feedline
designed for such a purpose, that often is the limiting factor for zip cord, speaker
cable, and other 2-conductor wires we often try to use for feedline at HF.


Title: RE: Ladder line using popsicle sticks
Post by: W6EM on November 25, 2017, 02:30:33 PM
Quote from: N7EKU

Since the wire will have the same insulation whether it is zipped together as it comes, or separated by the sticks, the loss won't be any different I think...



Actually it does make a difference:  that is one reason they put windows in
windowed twinlead.



The loss depends on how much of the field passes through the lossy PVC dialectic.
An air gap greatly reduces the losses.  Think of the dielectric as a resistor:
adding a larger resistor (air) in series with the resistances of the insulation
layers reduces the total leakage currents.  That's a simplification, but it
explains why the air gap is significant.

The PVC used in most wire insulation is much lossier than the polyethylene used
in transmission lines.  While dielectric losses are usually insignificant in a feedline
designed for such a purpose, that often is the limiting factor for zip cord, speaker
cable, and other 2-conductor wires we often try to use for feedline at HF.
From my old days playing with HV wire insulations in my employment many years ago, PVC is loaded with all sorts of clay fillers.  And, it tends to break down rather quickly from UV exposure in sunlight.  Carbon black is added to try to combat the UV damage, but it still is inferior to polyethylene as far as UV resistance is concerned.  PE normally doesn't have many additives other than some carbon black.  PVC isn't a very good insulation at higher voltages.....above 600V.  Sometimes, composites of PE and PVC are used.  PE is considered the insulation, PVC as jacket material......just like coax.  Off hand, I can't recall the dissipation/power factors of the two, but suspect that PVC is much higher than PE.  That's why its only a jacket at higher electric field strengths.



Title: RE: Ladder line using popsicle sticks
Post by: KD8IIC on November 25, 2017, 09:57:54 PM
  And after all is said and done, there is a U.S. made product known as True Ladder Line which is a durable
  alternative to this labor intensive drill.  :)


Title: RE: Ladder line using popsicle sticks
Post by: N4MQ on November 26, 2017, 05:24:58 AM
Popcicle sticks are going to fail and then your stuck.  I got some great 6" 600 ohm ladder line from ebay from a ham in alaska.  He makes it and it is #13 gauge wire.

His approach is really sturdy using black poly tubing as spacers that wont crack and are black with carbon so they are uv proof.  The spacers are drilled and fixed with urethane black sealant, really impressice.  My 860' loop is fed at the apex up 100' in an oak tree and I have no concerns that it will last.  Popcicle sticks are not worth the terrific effort on a good day, consider the investment in time over the cheap.  Woody


Title: RE: Ladder line using popsicle sticks
Post by: W6EM on November 26, 2017, 07:27:54 AM
Popcicle sticks are going to fail and then your stuck.  I got some great 6" 600 ohm ladder line from ebay from a ham in alaska.  He makes it and it is #13 gauge wire.

His approach is really sturdy using black poly tubing as spacers that wont crack and are black with carbon so they are uv proof.  The spacers are drilled and fixed with urethane black sealant, really impressice.  My 860' loop is fed at the apex up 100' in an oak tree and I have no concerns that it will last.  Popcicle sticks are not worth the terrific effort on a good day, consider the investment in time over the cheap.  Woody
Sounds like a terrific product..  Just curious, is the wire really stiff, IOW, hard-drawn solid copper?


Title: RE: Ladder line using popsicle sticks
Post by: KV7W on November 26, 2017, 07:54:46 AM
One good thing to have in the homebrew arsenal is some good epoxy, not the two part in a tube from the hardware store, but some good woodworkers/boatbuilders epoxy in qt. or gallon size from the marine supply store. It has so many applications.

Permanent spreaders out of sticks is pretty straight forward. If sealed in epoxy and painted - will last as long as, well, you do.

I made some field spreaders out of popsicle sticks years ago for my QRP camping rig. My design consideration was I wanted something highly configurable and simple, so I could make any antenna I wanted with a bag of spreaders and a roll of wire; I would set up a dipole at one site, a sloper at the next - without having to carry coax, (other than a short piece between the rig and the tuner). 

After messing with a lot of designs; drilling, notching, nylon clamping the ends; the fastest, easiest method was a three stick per spreader design. One stick is the width you want the ladder line spreader, make it 2" if you want 2" separation. Sandwich and epoxy this stick centered between two other sticks that are about 3/4" longer, leaving a 3/8" notch on either end. This makes a spreader that is the thickness of three sticks.

At the site I would zip tie the top spreader for strain relief and just use one rubber band per spreader for the rest, (takes about two seconds per spreader).

This makes a really strong spreader that's easy to make and will last a long time. Three sticks per spreader. The inner spacer thickness just needs to match the wire size. To permanently affix just epoxy the wire. One very important rule with epoxy is to add a filler and make a paste when using as an adhesive. Really fine sawdust works great. Mix your epoxy and then toss a little sawdust or talc into the mix - only use straight epoxy as a varnish coating. 


Title: RE: Ladder line using popsicle sticks
Post by: WD4HXG on November 26, 2017, 03:00:57 PM
Buy a bag of electric fence insulators (http://www.zarebasystems.com/zareba-4-inch-fin-tube-insulator-ht4fti200).
A bag of 200 is $15.00 plus shipping or check a place like Tractor Supply or AgriSupply and see if they have them
in stock. These are 4 inch long plastic tubes designed for use in sunlight i.e. lots of UV. Also buy a box of tie wraps. Thread
a tie wrap through the tube and around the wire on the opposite side of the tube then back through the tube. Then
on the side with the through retainer clip place the other wire and capture it with the cable tie also. Cinch it down
and clip the tie wrap. Voila, you have 4 inch spaced ladder line. If you insist on insulated wire buy a 500' foot of THHN
in the electric supply department of your local electric supply house. I prefer bare wire as you do not incur the losses
when old insulation gets wet during the rain.

YMMV

Chuck


Title: RE: Ladder line using popsicle sticks
Post by: N4MQ on November 26, 2017, 03:39:28 PM
Here is my ladder line material, solid for sure. Enjoy Woody

https://www.ebay.com/itm/LADDER-LINE-600-OHM-13-AWG-100-FT/132379883344?hash=item1ed274b750:g:mS0AAOSwDwtUobIb



My antenna site FYI:

https://sites.google.com/view/n4mq-site/home


Title: RE: Ladder line using popsicle sticks
Post by: KF4ZGZ on November 27, 2017, 02:40:59 AM
Buy a bag of electric fence insulators (http://www.zarebasystems.com/zareba-4-inch-fin-tube-insulator-ht4fti200).

This .....
I bought a smaller pack of insulators and a 100 pack of zip ties. Not counting the wire (5 bucks at an auction) less than $15.00 in 100 ft. of feedline.
Took about 45 minutes to assemble and it looks like I saved myself about 120 bucks!!!


Matt


Title: RE: Ladder line using popsicle sticks
Post by: KV7W on November 27, 2017, 06:24:38 AM
All these product suggestions make a fine addition to the homebrew forum - especially for something as complicated as ladderline.


Title: RE: Ladder line using popsicle sticks
Post by: N3QE on November 27, 2017, 07:21:07 AM
I think that can work fine as a temporary insulator.

In the distant past hams soaked dowels in spar varnish for extended periods to make ladder line insulators. I think the idea was to completely saturate not just the grain voids but also the fibers themselves. Results in a kind of a very primitive wood-based fiberglass.

I use 4" x 1/4" x 1/16" polycarbonate strips for my ladder line spacers and am very happy with them. I cut them from 1/16" polycarbonate sheet with plastic shears (kind of a giant pair of scissors), then put 1/16" holes about 3/16" from each end using a punch, then make a cut (again with the shears) from the hole to the edge. The cut at the edge allows me to easily (with fingers) slip a 14-gauge wire in. Solder blobs every foot or so on the wire, on either side of the insulator, stop the insulators from sliding up and down.

Polycarbonate is an incredibly nice material to work with. It cuts like butter and all forming operations can be done without any risk of introducing a crack.


Title: RE: Ladder line using popsicle sticks
Post by: WA2ISE on November 27, 2017, 05:46:46 PM
I've used election campaign signs material for RF spacers.  After you cut them up, no more QRM from the campaign.  ;D 

Try testing material for RF quality, by putting a sample in the microwave oven (along with a cup of coffee as a dummy load for the microwave oven).  If it stays cool, it should be good for RF work.


Title: RE: Ladder line using popsicle sticks
Post by: KX4OM on November 30, 2017, 02:01:00 PM
A better idea is to use plastic. Specifically, electric fence insulators. Zack, W1VT of ARRL HQ has written about using those for his homebrew ladder line. You can probably Google for that.

The ones that he used are from Zereba, 4: Fin Tube Insulators. The are obviously designed some high voltage and are weather resistant. Turns ourt that a 200-pack are currently on sale for $15.99.

http://www.zarebasystems.com/zareba-4-inch-fin-tube-insulator-ht4fti200

Ted, KX4OM


Title: RE: Ladder line using popsicle sticks
Post by: VK4XJB on December 06, 2017, 07:02:36 PM
For untreated paddle pop sticks I found 18 months was the upper limit before the ladder line had to be rebuilt with many of the spacers failing long before that. The ladder line was simple to make. Notch all the paddle pop sticks and I used either zip ties or a bit of glue to hold the wire in place. Cheap and easy to use but was not a long term solution.

My current spacers are cheap plastic coat hangers cut to length. In the last few years only broken spacer was something falling on it from higher in the tree.


Title: RE: Ladder line using popsicle sticks
Post by: KV7W on December 07, 2017, 07:53:12 AM
There's nothing more aesthetic than plastic, especially white or black PVC - not a ham wife out there that doesn't wish there wasn't more PVC hanging in the air.

Wood that has been base coated with epoxy and finish coated with spar varnish or enamel will last - there are a lot of old wood boats out there, in ocean saltwater and year around sun. Work well, last a long time.

Homebrew ladder line spreaders should be designed around 5" or 6", 600 ohms for most hams - the spacing for 450 ohm is just too critical. It can be done, but it get exponentially more critical the shorter the spreaders. Making a six inch spreader to use with 12ga wire can't be simpler, or cheaper. Again, the spacing on 600 ohm line isn't as critical as 450 ohm, so you can be off a little, or substitute insulated wire for bare. I've used a dollar bill to measure. Just remember 5" for #14, 6" for #12.

I made a spreader just for the thread out of some scrap cedar. It could have been any type of wood, pallet wood, pine, fir, whatever is handy. The pictures show three pieces glued together and how to use a rubber band to attach for temporary portable, (great for QRP backpacking rigs). To permanently attach the wire, just cut short pieces from the same spacer material and glue the wire into the notch. Any glue works - the wood is permanently sealed with epoxy and UV protected with spar varnish. 

https://photos.app.goo.gl/SBEq4ihtoBL4Zghi1

This is the basic unfinished spreader. These can be sanded down for any look you want. Use a dark color for the spacer for a two tone look. I doubt you can buy or build a better spreader out of plastic. No zip ties, no drilling holes or notching round tubing. 


Title: RE: Ladder line using popsicle sticks
Post by: WB6BYU on December 07, 2017, 08:28:07 AM
Quote from: KV7W

... the spacing for 450 ohm is just too critical...
 


That assumes that the impedance of the line is important.

There are some applications where this may be true - when you need to match 3200 ohms,
for example, you'd want the line close to 400 ohms (which is a better estimate for some of
the "450 ohm" window twinlead types.)

But for most common ham usage, the antenna impedance isn't particularly controlled, so the
impedance of the line isn't critical, and you can make it whatever is practical for your application.
I've used a 75' span with wires stretched between nails on the fences on either side of a field,
or a pair of "sort-of parallel" wires running through my attic and out through a vent. 

If you are using a tuner with it, the exact impedance probably doesn't matter.  If you are feeding
a 600 ohm antenna with 600 ohm line to a 600 ohm transmitter, then it does.


Title: RE: Ladder line using popsicle sticks
Post by: KV7W on December 07, 2017, 01:45:43 PM
Quote from: KV7W

... the spacing for 450 ohm is just too critical...
 


That assumes that the impedance of the line is important.



But for most common ham usage, the antenna impedance isn't particularly controlled, so the
impedance of the line isn't critical, and you can make it whatever is practical for your application.
I've used a 75' span with wires stretched between nails on the fences on either side of a field,
or a pair of "sort-of parallel" wires running through my attic and out through a vent.

This is speaking to two different things, a high standing wave impedance on the feed line and matching different impedances. Coax is truly a wonderful thing in some applications.

"Sort of parallel" kind of defeats the purpose of using a feed line with a potential velocity factor of 98%. It takes a little more work; the part swinging in the wind is on it's own, but station mounting is another thing. Parallel is kind of important - it puts the twin in twin feed. I think most have done the attic thing, lol. A well done feed line means free power. I don't care if the twin feed has a high SWR, as long as it didn't originate on the twin feed from my install.  Rhombic antennas always reminded me of twin feed gone wrong - wish I had the property.