Parallel Transmission line

[KB2WIG]

Having decided to bite the bullet, I've been looking for various ways to 'do up' ladderline.

This is an interesting method and material....

http://www.youtube.com/watch?v=D--K4Uc5p0I


Coat hanger and pull-ties. I'll probably go with this method; everything at wallmart or in the tool box.

http://www.kr1st.com/hfcoath.htm

Anyone with somecheep spacers?

Any comments??

klc

[KF1Z]

You really can't get much cheaper than 1/2" pvc pipe, chopped up into 4 - 6" or whatever lengths.
Could drill holes in each end, or use the wire-tie method.
All of course mentioned in other threads.


I have some ceramic 4" spacers... but heavy, and not comparably "cheep".

[W1AEX]

I have had excellent results with 1/4 inch polyethylene tubing. It's the stuff used for refrigerator ice maker plumbing and costs a few bucks for a 25 foot spool at Home Depot. It is rigid enough to support 4 inch spacing, but probably no more. I just cut it up into 4 inch lengths, slot the ends and snap the wire into the ends. When they are all in position, I walk along with a hot glue gun and seal up the ends. It's very sturdy, weather resistant, and works equally well for fan dipole assemblies. It took me about 3 hours to make 130 feet of feedline.

[Ed/KB1HYS]

Nice job with the poly tubing! much easier than my solution.

I grabbed a few of the 1/4 inch fiber glass "driveway markers" and cut them into 4in lengths. Drilled holes at each end.  Sturdy, probably last forever for me, a little heavier than the poly tube. though

[Jim, W5JO]

Be sure to use something that can withstand UV.  Sunlight is the big killer of most substances.  I have seen window line completely deterioriate in less than 5 years in New Mexico.  You don't want to be redoing it in a short period of time. 

[The Slab Bacon]

3/8" white PVC pipe also works good. Light, cheap, and available at home dumpo. I use it for my antenna spreaders, and it has been up close to 10 years now.

[WA1GFZ]

When I was doing my vent stack I asked the building inspector about PVC and he told me all the new PVC pipe is ok in the sun

[flintstone mop]

That guy on YouTube is making 600 ohm worthless transmission line. And using stranded color coded wire.........geeesh! What happened to #8 solid??

Pulling chains here.......................laughing sounds please.

Phred

[W9GT]

I also used 1/2" PVC pipe/tubing.  Works fine for me.  What's wrong with 600 ohm line Fred?  I used 6" spacing and #12 THHN insulated wire, just 'cause that's what was available and it works FB OM for a 600 ohm line!  Those old buzzard porcelain spacers are cool, but very heavy and fragile.  I had a bunch of them, but learned the hard way that they are not very durable and become quite heavy with a long length of line.

You can use plastic hangers. ladies' plastic curlers, driveway marker fiberglass rods, ball point pen barrels, even pieces cut out of old plastic milk jugs for spacers.  It all works and it all provides a cheap, but effective low loss transmission line.

73,  Jack, W9GT

[KB2WIG]

Gud ideas gents.....  I was leaning towards the coat hangers as the black won't stand out as much. Trying to keep the Xyl somewhat happy. The feedline will exit on the garage side, so she'll see it when she comes up the driveway (The last 120 feet is at a 10 deg rise).....


klc

[W1AEX]

Be careful with the black coat hangers. They could contain lampblack (carbon black pigment) which may have conductivity at RF. This was pointed out to me on the board back a few months ago. I did not test the pile of black (Walmart) hangars I picked up, but it seems like something to check out before you invest a lot of time and effort!

[flintstone mop]

I also used 1/2" PVC pipe/tubing.  Works fine for me.  What's wrong with 600 ohm line Fred?  I used 6" spacing and #12 THHN insulated wire, just 'cause that's what was available and it works FB OM for a 600 ohm line!  Those old buzzard porcelain spacers are cool, but very heavy and fragile.  I had a bunch of them, but learned the hard way that they are not very durable and become quite heavy with a long length of line.

You can use plastic hangers. ladies' plastic curlers, driveway marker fiberglass rods, ball point pen barrels, even pieces cut out of old plastic milk jugs for spacers.  It all works and it all provides a cheap, but effective low loss transmission line.

73,  Jack, W9GT

Not a thing Jack........just pulling chains. I had a thread elsewhere about my ammeters not reading after I changed my system out from 450 ohm window line to the real 600 ohm ladder. I'm very happy with my new setup.

Fred

[WD8BIL]

Be careful with the black coat hangers. They could contain lampblack (carbon black pigment) which may have conductivity at RF.

A few seconds in the microwave will tell the story! Looks pretty cool though.

[W2INR]

Kevin ,

I have ceramic 6" spreaders that you are welcome to . I think I have about a dozen.

You want to use a few as necessary. The more spreaders the more capacitance you are adding to the system. I had a 200 ft run that ran horizontal and it had only 4 spreaders and then it went 60 ' vertical with 4 more.

The system worked well until I went with my current system the directional array which I used coax. I miss the open line because it allowed using many frequencies but the array can out "hear" the other system.

G

[WA1GFZ]

Gary I could use them if you don't give them away. I have 13 and need some more for a lazy H I want to build. I'd pay for them even.

[Ed/KB1HYS]

Be careful with the black coat hangers. They could contain lampblack (carbon black pigment) which may have conductivity at RF.

A few seconds in the microwave will tell the story! Looks pretty cool though.

If your using insulated wire, I doubt the pigment of the black plastic would hurt too much. 

[KF1Z]

A LOT of plastics that don't contain carbon melt easily in the microwave....

How would you tell if the material is conductive at RF frequencies, just by putting it in the radar-range?

[KB2WIG]

G,
Thank you very much...The ceramicspreaders  sounds like an easierway to go. A PM follows.

"the array can out "hear" the other system"

 Maybe i'll try a beverage or two in the spring. I've got about 1300' east-west to play with."

"How would you tell if the material is conductive at RF frequencies, just by putting it in the radar-range"

Bruce, that'll tell u that it absorbs energy at that particular frequency. Whether that helps??, don't know.  I'd guess that running some ladder line made with the material in question into a dummy load at a particular frequency may give a better data point.  Or just wire up and test it that way.

Again, to all youse that made comments, thank you.

klc

(Buddley, joan crawford will thank you)

[K9ACT]

That guy on YouTube is making 600 ohm worthless transmission line. And using stranded color coded wire.........geeesh! What happened to #8 solid??

Not sure I understand what makes it worthless nor what makes #8 solid any better that stranded?

Frankly, I think aluminum fence wire is about the best all around antenna wire there is at our humble power levels.

What I found most interesting was his squeezing the wire to get a press fit.  If you did this right, you might not even need the hot glue.  Very clever.

js

[ke7trp]

I commend the old guy for making his own.   Probably got the time.  Why not?   

I picked up a bigg stack of brand new Ceramic insulators at a ham fest. Look like 6 inch.  The thing about using them is they are so heavy.

Anyone have ANY idea about the power capability of 18, 14 or 12 or 10 AWG ladder line?   

C

[WV Hoopie]

ke7trp,

I've used the 1/4 inch "driveway markers" and #14 solid copper. Cut the fiberglass rod to about 5-1/4 inches in length, notch the ends for the #14, and then drilled a hole a little farther inside to loop a 1 inch piece of #14 around the parallel line to hole everything together. Spacing is about 5 inches for somewhere near 600 ohm line.

The Junkston Desk KW can run full strap on this line feeding a 40 meter dipole.

On 75 meters, I feed the ends of a full wave loop to a Junkston KW matchbox. The loop is made of #14 THHN. The Desk and a "500" are quite happy and haven't started any fires in the neighborhood yet.

wd8kdg
craig,

[ke7trp]

Ok.. I have 16 gauge stranded.  I hope I dont light it on fire.. LOL


C

[K1JJ]

Anyone have ANY idea about the power capability of 18, 14 or 12 or 10 AWG ladder line?  

C

It depends greatly on the mismatch of the system.  If there is a huge swr, then you will have current maximas that are so large it will heat up certain diameter wires. For example, I once fed a W8JK that had an input of about 5 ohms. I used very heavy open wire line, like #5 wire spaced 6".  Running a KW, the openwire actually arced across from the voltage maximas.  The current maximas had to be huge too, but the large diameter wire handled them without obvious heat.

There are cases of guys melting that brown plastic openwire when feeding say, a 40M dipole on 75M. The mismatch was high.

So, generally, if you run 1500w pep on AM, use at least #14 or #12 wire for normal use when the flat top is at least 1/2 wavelength long on the lowest freq. If you want to feed a dipole that is only 1/4 wave long then you will need much heavier openwire diameter and a strapping tuner of large diameter coiling and hardware. But bear in mind that on the higher bands you will have some spots that have large mismatches, so try to use larger diameter wire, like #10 if you can for multi-band 10M-160M use.

But the easiest way to check is to load up the antenna on various bands, drop a BIG carrier for a few minutes (on a clear freq) then unkey and feel the openwire for at least 1/4 wave up and down its length looking for hot spots.

T

[ke7trp]

Ok..  Thanks for the info.  Its a KW AM.  The antenna is resonant a 3900.  Open wire, flat top. Going to use it in the ghetto. I think I should be ok.  Time will tell

C

[K9ACT]

Anyone have ANY idea about the power capability of 18, 14 or 12 or 10 AWG ladder line?   

C

So, generally, if you run 1500w pep on AM, use at least #14 or #12 wire for normal use when the flat top is at least 1/2 wavelength long on the lowest freq. If you want to feed a dipole that is only 1/4 wave long then you will need much heavier openwire diameter and a strapping tuner of large diameter coiling and hardware.

Good to know numbers.

Now the questions are:

a. Do these apply to the flat top portion also?
b. Does the surface area of stranded vs solid offer an advantage?

and a sort of unrelated question:

I am going to take down my 80 meter steel fence wire dipole and replace it with aluminum fence wire.

As long as I have to cut new wire and I can make it any length I want,  I am having a hard time finding anyone to suggest a best length for the flat top.

The present setup is very usable on 80 through 20 using a tuner and 450 ladder line (the brown plastic stuff).  I only run legal limit on 80 and about half that on the other bands (different transmitter).

I run a net every day on 3870 so I want max performance there and elsewhere can be a compromise.

If I ever stumble into a big tuner that covers 160, I guess I cold eliminate the 80 meter dipole completely and put the 160 where it is.

I assume that a 160 open wire fed with a tuner would work as well as the 80 on 80?

So, I guess the question is, is there an optimum flat top length for 3870 that will still allow 40 and 20 operation?

js