The AM Forum

HEY GANG,
I bought some 1/2 in. poly tubing for spacers, and have the 14ga stranded house wire from my old loop antenna. My question is, what would be good spacing for HB open line feeder? I know, kinda a JN question, but seems its kind of a lost skill. I plan on a large doublet, probably inverted V configuration. So, what are you folks with open line use for your setup? Thanks!
Norm K7NCR

I've had good luck with 30 inch spacing

Is that between wires Frank?
or
Between spacers?

 :D

I am using the open wire that was sold by W7FG. He used 16 ga stranded insulated wire with what sounds like similar material for spreaders that you are going to use. The spacing on his feeders was approx 4" and was spec'ed at 600 ohm.  I use it with a 130' flat top and a Viking KW matchbox and it does a fine job.
W7FG is now a SK - I know the question has been asked, but has anyone heard if his antenna business will be continued?

I don't think you could make that feeder line for what W7FG charged.  Website is still active, dunno if they're still shipping or not  http://www.w7fg.net/

That was my question for the original poster.  Generally 4-6" wire spacing is FB. Spacing down the line (between adjacent spacers) depends on the stiffness of the wires used and/or if the feedline will be held taut. If the wire is taut or very stiff. very few spacers are required (in some cases none). If the wire is flexible and not held taut, place as few spacers as is need to keep the spacing between the two wires fairly constant. Less than one every few feet is probably overkill.

Actually I was looking for spacing between wires. With 14ga stranded, it is fairly flexible. What is the distance between spacers on the W7FG line? As I already have 500 ft of the wire, I only spent $16 on 50 ft of tubing. Thanks for the input so far!
Norm K7NCR

Hi Norm,

I've always had good luck with 3 inch spacing between wires with the spacers inserted in 1 foot increments. I also used stranded wire for the feedline and found that it had a tendency to twist a bit in the wind. The 1 foot increment preserves the 3 inch spacing and makes it pretty much impossible for anything to short out in the wind should the feedline get tossed around. After slotting the ends of the spacers and putting them in place along the parallel wires I just walk along with a hot glue gun and fill the ends of the spacers. The glue firmly locks the wire to the spacer to form a series of very durable junctions that have proven to be resistant to mechanical stress, weather, and ultraviolet effects.

Rob AEX

The nominal spacing appears to be somewhere around 18 - 20" but since the ends of the tubes are both slotted and drilled it is easy to "slide" the spacer along the wires to give optimum spacing in places that may require more or less.

Since you already have the wire and the cost for the spacing materiel was low, you will definitely save some $$ but since time is at a premium for me, the extra cost was well worth it.

Here is a photo of my installation:

Just in case you run across the opportunity to do so:

I've run open wire that had NO spacers and was spaced 24" apart between the two wires.  By using a tower or strong tree as the center support, simply pull the wires tight to the ground support.  No ice or rain bridging between wires causing swr changes. Though, the wind will cause a sway to the wires causing an oscillating swr effect... :-)

24" spacing is still a small % of wavelength, even on 40M and will cancel FB...  It was actually the most environmentally stable openwire installation I ever had.

Tom, K1JJ

I know one thing - I'm gonna freak on every large set of ceramic spacers I see on this years fests. Sometimes you find large batches of em. IMHO most hams today dont even know what they are.

I need a slinging transformer. I can still throw one.

I still remember the club station at school that used the 600 ohm 'railroad track' line. I used to see gobs of that stuff in boxes under hamfest tables. Now I wish I would have scored it whilst I had the chance.

I would not order at this time.  I have not heard from his widow what will become of the business.   The way it was set up was rather tricky so I really doubt it will continue but, until someone receives an answer, I would hold off ordering.

I run Johnson 4 inch spreaders spaced 30 inches with #10 solid. I have run #14 but it needs to be closer say 24 inches. I have a run that has been up since '83

The old classic standard was 6" spacing, using #10 or #12 wire, to make approximately 600-ohm line.

Mine is made of #10 copperweld, spaced 2" apart, using the little EF Johnson ceramic spreaders.  The line that goes up the inside of tower to the dipole is the same spacing and under tension with turnbuckles, held in position by threading through plexiglas spacers every 10 feet, that rest on the rungs of the tower, one each tower section.

Here are some photos of the progress so far. The close-up of the wire test piece it pretty fuzzy. I drilled a hole slightly smaller than the wire, then notched the tube to the hole. The wire snaps in firmly, and only slides with moderate force. Have to get all the insulators drilled/notched, than can start assembly.

Should work out fine - that is the way the W7FG spreaders are made - they can be slid along the wire but it does take a little pressure and they don't move on their own.

If the W7FG feedline turns out to be no longer available, your method will produce the same result, albeit with a larger labor/cost ratio.

Keep us posted

If you make the slot short enough, you can glue an end cap tightly against the wire
to keep it from moving.

His website states that the business is being transferred, and that they are accepting orders.  Is that not the case, or do we have reason to doubt that?  It's on the SK portion of the main website.

--Shane

I think the snap-in slots will be enough. I want to keep the mass low, if possible. I'll keep everyone posted.

I Took a look at the W7FG site and yes, it  says  they are still taking orders  BUT, there was NO word as to if they were SHIPPING product!

I planned on ordering this line and sent email. I got no response.  Looks like a solid product at a good price. If they contact me, I will let you guys know.

Clark

Here are some more photos. I set up a jig in the basement, about 30 ft. long. I need about 120 ft. I have completed 2 runs, (60 ft) so far. It goes pretty fast after the tedious job of drilling and slotting. The weather here is finally improving, so I hope to get outside to the antenna work soon! 73! Norm K7NCR 

Any response yet?

It is a great product and a great price.  I need some more...

Nope.. Nothing.  I am ready to order also. Just dont have the time to make my own right now. I am using 14 guage stranded 450 now. I would rather have the big stuff up.

Clark

What do they charge?

I have a box of their open wire line, its been sitting in my basement for years, I tried to sell it at fests for $20.00 with no takers....

I think its 100 feet long.

If you was to ask me, its not great stuff, I would want thicker solid wire and better spacer attachment.

Its good to go overkill here, do it once, do it right, and be done with it.

The antenna can break, but you can reuse the open wire line...

I was going to take it to baltimore fest...


Brett
N2DTS

OK gang, I got the antenna up and the feedline into the shack and hooked up. I have some basic tuner settings worked out, so will give it a try. I will post some photos, too. The wire loop is made with 14ga green insulated wire. Very stealthy!
Norm K7NCR

I was contacted.  I emailed and then purchased 120 feet of this stuff. SHould be here next week.

I will let you guys know.

Clark

I still have not recieved my open wire line. However, I did get an email that said it was shipped. 

I did find some of this stuff at a local ham fest. There, sitting on a table was 100ft of this exact line ordered from this same website new. I got it for a steal. I guess nobody wanted it.  The man ordered it when the original owner was still around and never used it.

Yesterday, I lowered my 136ft horizontal Zepp and cut the 450 ohm line off. Good thing, It was cracked and weather beaten after only 1 year in the AZ sun.

I attached the new 600 ohm line with a 2 ft feeder length. Now my overall antenna is 140 ft. I ran the 600 ohm line 2 feet off the ground with it tied to different objects to get it off the ground and away from the house. I removed two of the spacers, drilled two small holes in the wall and pushed the wires through to the shack. Then on the inside, I put the spacers back on. I only have about 1.5 ft in the house where it attaches to the Johnson KW matchbox.

I pulled the antenna back up to 65 ft flat top.

I can now tune FLAT 1.0/50 ohms on 10,15,20,40,80 with the KW matchbox. The nice thing is that the Dials are normaly mid mesh. Before, Some bands where off the dial scale to tune. It tunes smooth too.

I am very happy with this product. Especialy since now, with my Palstar tuner inline, I can tune 160 meters! With the 450 ohm line I could not get even close.

I have an inverted L up for 160. I am going to compare both the inverted L to the Flat top on 160 tonight.

I ran the globe king 500C at 300 watts all night on 75 meters without issue.  The 450 line got over the Computer speakers in the bedroom. Nothing heard with the 600 ohm line. No RFI or TVI that I can find with the 600 ohm line. Nothing is getting hot or even warming up.

As for performance? I cant tell yet. I swear its better but i could have been the band last night. I will have to use it for a week or two before deciding. ITs at least as good if not better. I am seeing some gain but again, I want to reserve that for a few weeks of testing.

Good stuff!

Clark