Curtain antenna

[wavrider]

I am curious as to what type of curtain antenna's anyone has built, installed and put on the air?

What was the performance of the antenna like,compared to a dipole, the gain, direction, BI- directional or just forward gain, and the nulls of the antenna. How high was the antenna installed. Polarization of the curtain.

Also was the curtain a mono bander or multi band?

 

[RickC.]

Bobtail? Sterba?

I had a Bobtail array for 20m 30 years ago that I was able to use for exactly three days before the wooden fence that supported it was destroyed in a storm!

All I can say about that one was I lived in an area with really high electrical noise (Texas City, TX, lots of chemical plants and refineries) and while it had noticeable gain over the dipole in the desired azimuths, it also picked up the noise much worse. That was probably a worst-case scenario for that antenna, though.

I used to work Ozona Bob (and I cannot recall his call now) on 10m AM in those days and his Sterba Curtain was famous. I don't recall ever working another amateur who used one, but that doesn't mean they're not out there.

 

[wavrider]

Thanks for reply RickC.

I am mostly looking for info on the LAZY H, I know BJ radionut runs a Lazy H in a vertical configuration if I remember correctly.

I am looking for an alternative to putting up the Mosley PRO67B.

That is a big honking antenna with lots of weight.

I do have the real estate to install three Lazy H antennas and should give me global coverage, for 40 meters through 10.

I have talked to a few guys who said they used to run the Bobtail, one op in France screams in on 40 with his Bobtail curtain, of course it is mounted not to far away from the beach.

I do not know any one who has built and installed one horizontally that I can ask about any do's and dont's for the antenna construction

 

[RickC.]

Interesting! I don't think I've ever run across anyone using a Lazy-H, I know them only from antenna books. What a great situation to have-- enough room for THREE of them! I'm guessing you'd dimension them for 40m and use open line feed for them, and a balanced tuner? Sounds like my kind of undertaking!

I can't get my mind around a Bobtail in the horizontal plane. How do you envision that working?

I suppose you could use a 40m Bobtail on 15 if you used current feed. Other than that, I'm trying to think of a solution to the multiband issue with a Bobtail-- can't think of one at the moment. What do you have in mind?

 

[wavrider]

I put one lazy H up in a NW-SE heading. Worked Great for DX into EU, good into the New England states and out to 6 and 7 land.

10 through 40 meters. As the literature states the lower in freq the less gain it shows.

Feed was 450 ohm ladder line into a 1:1 current balun, then small run maybe 5' rg-213 into the shack and the Tuner.

I made each leg 39' long. Spacing between top and bottom leg was 33'. top leg at tower was at 58 feet, in the pine tree maybe at 48 feet.
It screamed on 10 meters and performed nicely on 17.

Down side it is pretty directional deep nulls off the end of the wires, need to use an antenna coupler, although the doublets seem to be resonant on 15 meters less than 1.7:1 VSWR. I think feed line length played a factor in that.

So I cut the bottom off and made another 40 meter doublet that will work 10-40. Left the upper leg at original heading and height.

Second 40 meter doublet installed West-East. that way I had some more coverage of the main lobes switching between the two doublets.

Switching between the two I did see as much as 18-20db difference on receive depending on where the transmitting stations location was.

Findings: The Lazy H outperforms a single doublet on all bands except lowest freq. In my case 40 meters. So if I get the itch for more antenna building I will definitely install the Lazy H again.

On the other hand I sunk the anchors in the ground and poured the concrete so I can put up the Mosley PRO67B, looks like the solar cycle is starting to pick up and I would be upset if I missed the rare contact because I was experimenting with wires. Time to put that monster yagi in the air and let it work some DX.

 

[wavrider]

I can't get my mind around a Bobtail in the horizontal plane. How do you envision that working?

I suppose you could use a 40m Bobtail on 15 if you used current feed. Other than that, I'm trying to think of a solution to the multiband issue with a Bobtail-- can't think of one at the moment. What do you have in mind?

The bobtail performance depends on the ground/soil conditions a lot. the antenna itself is a no radial ground plane, but it still seeks ground. Monoband performer.

Look at an N4GG array.http://ars.nc4fb.org/antenna-articles/n4gg1.pdf

I played with this on 11 meters, ( great test band as antenna are small size).

I heard DX on the array that I did not hear on the 4 element yagi at 50' or the imax at 70', yet the N4GG array heard the dx and I was able to make the contact. Ends of the array was only 9' from the ground, feed point at 18' or so. Very little high angle receive. Locals could not hear me working the DX, they could not hear the DX station either.

To me the array is just phased verticals 1/2 wl seperated, PRO is no tuner required and can be made multi band as the article states.

CONS, narrow beamwidth pattern, But if you can move one end of the array and say work into EU in the mornings and early afternoons then change the direction and work the JA's and Asia in the evenings it might be a decent wire antenna to have on the farm.

QST this month has an article on a portable beam made of wires and a 40' fiberglass pole for apartment dwellers, It was a cool article, the issue is in my truck or I could tell you who wrote the article, depending on the band it is a three or four element wire vertical yagi, pretty neat.

 

[RickC.]

My September QST just happened to come in today. The article on page 98 is interesting, but lacked detail. Then I went to QST-in-depth.

WOW.:blink:

What a great presentation. I've done antennas and feedlines for a living for a long time now, and rarely have I seen this kind of information presented this well. I'll have to go back later and look at it several times to get it all.

Also, rarely have I seen anyone go to these lengths for an indoor system. This fellow knows what he's doing. I'm still shaking my head. I can't get this kind of analysis from antenna manufacturers who want me to spend money with them, and this ham knocks it out of the park!

Thanks for the info on the N4GG array. Interesting. I think if I had the room I'd probably just go with a voltage fed Bobtail unless I needed the multiband capability, but that's a neat way to do that.

Do you have any pics of your Lazy Hs? I know it's hard to get wire antennas in pics sometimes, but I;d like to see them and I bet many others would also.


Rick

 

[pro151]

I tried this design but I never could get the Ess Double-U-Ares low enough to use it. :laugh:

 

[RickC.]

Nice ruffles.

 

[pro151]

Everyone has to be somewhere and everyone has to be something.
I figured tonight I would be here and be the comedian (read smart-ass) in this thread. :tongue:

 

[RickC.]

Ha!

 

[wavrider]

Everyone has to be somewhere and everyone has to be something.
I figured tonight I would be here and be the comedian (read smart-ass) in this thread. :tongue:

If you take the decorations off the antenna ( curtain rod) attach your coax and adjust (slide) the curtain rod antenna in or out you can adjust them vswr's.

Friend of mine made a six meter curtain rod dipole, he actually made some contacts on it into the SW states.
Go figure

 

[wavrider]

Rick I cut the bottom leg off of the Lazy H and made to 40 meter doublets so I can have more coverage direction wise..

the articel in QST mag is good about that fiberglass pole beam.

You found an in depth article on it? I would like to read more as like you said this guy seems to know his stuff.

http://techdoc.kvindesland.no/radio/antennas/20061010170744620.pdf

Good article on the lazy H I built mine almost to a T as this one, and it seemed to perform about like the author said it would..

I discussed the N4GG array with another ham friend of mine, We have both been into experimenting with antennas long before we ever got one of them license things.

After talking with him I think I will try next the N4GG array for 10/12/15 meters coax feed. 15 has been wide open the past few days.

do not know if it will work like a fan dipole or if there will be to much inter action with the elements.

If I can not get the vswr down I will feed it with ladderline to see how it works out.

May turn out to be an easy cheap way to get some gain out of a vertical wire antenna. Or it may be a waste of time.

 

[RickC.]

Wavrider, we may not be talking about the same article-- I had a band rehearsal tonight and have not had time to go back over the QST article, but I don't recall seeing a 40' pole mentioned. I've not yet gotten the October issue, is it in that?

Keep us posted on what you find on the N4GG array you're testing. I have spent very little time on 15 in recent years, though I lived on the band in the late 70s/early 80s.

Good stuff, this!

 

[wavrider]

RickC

It is indeed the Oct 2011 issue, article titled "The DK7PE Jumper Beam" page 42.

I will keep you up to date on the N4GG array when I get a chance to build it, between helping the kids with homework and the wife's honey do list I get little time to "play" radio.. I had more time to play radio when I was working full time than I do now since I am retired.