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ladder line fed vertical

Lazybones1222

Lazybones1222

W9WDX Amateur Radio Club Member
Apr 6, 2005
948
28
28
Tampa Bay Florida
Any one ever try using 450 ohm window line to feed a Vertical antenna like a Maco V58?

I know it is a 50 ohm feed point currently resonant on 11 meters, but I use a big old tuner to get on 10 and 12 meters anyways.

Window line is so cheap and efficient, I was wondering if anyone has ever tried it.
 

I guess no one has tried it with that particular antenna.

I've tried feeding a vertical with ladder line and it did 'work'. Not well by any means, but then it wasn't going to, no matter how it was fed. Antenna was REALLY out in left field for where I was trying to tune it. So don't take that as any kind of recommendation or whatever, it wasn't comparable to what you're asking about at all.
My biggest 'happiness' with ladder line fed antennas is that I just don't particularly care what the input impedance is, or the SWR. The tuner handles all that, and makes the power (most of it, anyway) go from the transmitter to the antenna. So far, no big objections from the transmitter, tuner, or antenna. I typically am heard, which is the whole point. Loudest thing on the band? ... Oh, Yeah! Yeah! You bet! (not even in my dreams!;)). But it works.
- 'Doc
 
snip:
W5LZ said:
My biggest 'happiness' with ladder line fed antennas is that I just don't particularly care what the input impedance is, or the SWR. The tuner handles all that, and makes the power (most of it, anyway) go from the transmitter to the antenna. - 'Doc
Click to expand...

That is what I was thinking. Screw the SWR, full speed ahead.
 
That ladder line can handle a wide range of impedances, but only stays balanced if its kept away from any metal, such as the mast. You would need to work out some kind of spacers to keep it held away.

You would probably want to try it with a 1:1 balun since that antenna is designed to be 50 ohms.
 
Very good Dudmuck and that make total sense. Forget the spacer even, you could never get the balance needed to even come close to using the advantage predicted. The lack of balance is the big issue and is even more accute in a 5/8 wave vertial. Maybe one could get by with a quarter wave designed vertical, but I even doubt that would be effective.
 
Lazybones1222 said:
...I know it is a 50 ohm feed point currently resonant on 11 meters, but I use a big old tuner to get on 10 and 12 meters anyways...
Click to expand...

i first saw this thread yesterday, but i was waiting to see which "direction" the replies were going to go.

will it "work"?.... well, sure..... but..
you have a resonant antena...... WHY do you want to feed it with ladder line via a tuner? the advantage of ladder line is the lower loss to a NON resonant antenna and loading it on multiple bands via a tuner.

in the real world, you will really gain nothing by feeding a resonant antenna with ladder line as compared to properly selected coax. some coax has the same (and even lower) loss/ft than ladder line depending on the freq.


Coax Calculator
@28 mhz
450 ohm ladderline has a loss of .15 DB/100 ft
heliax has a loss of .13 Db/100 ft

the only advantage i can think of is the cost.

don't get me wrong, i use ladder line to feed all my multiband non-resonant antennas and it works(y). but for a resonant antenna, i use coax.
 
Hello Lazybones:

Yes this can be done using ladder line. But you will need Impedance and Balance matching device at each end of the Ladder Transmission Line. So now you will need the Ladder Line, and two 50 to 450 OHM transformers or matching devices. And the Ladder Line will need to exit the bottom of the MaCo V 5/8 at a angle.

And its a possibility that the matching transformers will have to adjusted to work right, to get it all humming the right way. The ARRL Book on Transmission Line Transformers might be a help. See:

ARRLWeb: ARRL Product Catalog

The MaCo V 5/8 will probably work better with just good old LMR 400 Super Flex Coax. And probably cheaper and easier in the long run. I can't see were your gaing anything using the Ladder Line.

The Ladder Transmission Line works great feeding a dipole or other Balanced Antenna. I have used the ladder line and a antenna matching unit feeding a long dipole antenna for the ham bands and had mixed results to great results. This is what the ladder line stuff was made for. Coax replaced the Ladder Line Transmission Line just after WWII as it now able to be routed near metal and near other coaxes.

Or you could remove the matching system from the MaCo V5/8, and feed it with the Ladder Line, and use the Big Antenna matching Unit and see what happens. You will need a Balanced to Unblanced Transformer at the antenna. This will take some doing with a antenna analyzer and VSWR and Field Strength Measurments. But would increase the Broad Band use.

Hope this helps.

Jay in the Mojave

Lazybones1222 said:
Any one ever try using 450 ohm window line to feed a Vertical antenna like a Maco V58?

I know it is a 50 ohm feed point currently resonant on 11 meters, but I use a big old tuner to get on 10 and 12 meters anyways.

Window line is so cheap and efficient, I was wondering if anyone has ever tried it.
Click to expand...
 
Last edited:
hookedon6 said:
i first saw this thread yesterday, but i was waiting to see which "direction" the replies were going to go.

will it "work"?.... well, sure..... but..
you have a resonant antena...... WHY do you want to feed it with ladder line via a tuner? the advantage of ladder line is the lower loss to a NON resonant antenna and loading it on multiple bands via a tuner.

in the real world, you will really gain nothing by feeding a resonant antenna with ladder line as compared to properly selected coax. some coax has the same (and even lower) loss/ft than ladder line depending on the freq.


Coax Calculator
@28 mhz
450 ohm ladderline has a loss of .15 DB/100 ft
heliax has a loss of .13 Db/100 ft

the only advantage i can think of is the cost.

don't get me wrong, i use ladder line to feed all my multiband non-resonant antennas and it works(y). but for a resonant antenna, i use coax.
Click to expand...


Ditto
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Ditto? ditto? ......you provincial putz!
Harvey Korman, Blazing Saddles
 
A 5/8 wave antenna is not a resonant antenna.
Balance just isn't going to be that hard to do/get. Ever see an end fed 'zep'? It isn't 'balanced'. (Used to hang from a zepplin/blimp, and where the name came from.)
Sure there's some loss of efficiency. But ladder line isn't typically damaged by really high standing waves like coaxial cable is. Seems like a fairly good 'swap, some efficiency for a longer life span for the feed line undr odd conditions.
Is ladder line, or any balanced feed line the 'cure all' for antennas? Nope, but it can sure be handy at times.
So, half of the original question's answer is, yes, it can be done. No idea what the answer to the other half of that question is, about using a 'v58'. Is it worth doing? Only if you want to.
- 'Doc
 
Last edited:
A Maco 5/8 no. Others yes.

One was a 44 foot piece of wire fed in the center with TV twinlead pulled off at a right angle by string. The wire itself was hung from a tree branch. It was slightly off vertical to keep it away from a few things in the yard. Worked OK except for having to retune the Johnson Kilowatt matchbox whenever there was any precip. TV twinlead sucks compared to true open wire line when it gets wet. I used to arc over various experimental insulators at the feedpoint of this thing. There is plenty of voltage at QRO.


Second setup does not directly answer the original question but might give some food for thought. It was Radio Shack .64 vertical with it's base insulator, radials and factory matching coil removed. I used 20 feet of aluminum and 20 feet of #8 THHN wire pulled away from the tower but almost vertical tied off with string. The whole thing was remote tuned with the network built in a weatherproof electrical J box from Home Depot. I cheated and didn't run more that a couple feet of feedline to the tuner box. That antenna worked very well at 82 feet in the center. Setting up the tuning box took a lot of time. It used the balanced balanced design with a motor driven tuning capacitor.

Necessity of a matching device on both ends of a balanced feedline is only correct when you wish to run the twinlead at it's characteristic impedance. No reason to need more than one matching device as the twinlead will have low loss even at high SWR.
 

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