eHam

eHam Forums => Antennas and Towers and more => Topic started by: AE5X on June 21, 2012, 04:17:54 PM



Title: Why so many more Yagis than quads?
Post by: AE5X on June 21, 2012, 04:17:54 PM
Evening folks,

After 34 years in the hobby I'm finally having a tower installed. Up to now it's been dipoles; 288 countries' worth (no, it didn't take 34 years to ge tthat count). But it's time to move on...

The tower will be a 50' Rohn 25 installed behind my garage and I have to decide what antenna goes atop it since the installer will be putting up the antenna as well as the tower.

I gotta say, the quad (2 el GemQuad) looks good compared to 3 and 4 element Yagis - lighter weight, smaller turn radius, equivalent gain and the ability to be WARC-capable simply by adding the wire. I live in STX so there are no issues with snow/ice.

A 20 ft turn radius is available - a sweetgum tree prevents more - that will accomodate the quad (easily), or a 3-4 element triband Yagi. It's a tough decision.

If anyone else has been down this road, as Ross Perot says - I'm all ears.

TNX/73,

John AE5X
http://www.ae5x.com/blog



Title: RE: Why so many more Yagis than quads?
Post by: KH6AQ on June 21, 2012, 04:32:09 PM
  • Yagi's last almost forever whereas the wire on quads does not.

    Installing a quad is an experience being that it's three dimensional.

    Yagi's can have better ice and wind loading capability.


Title: RE: Why so many more Yagis than quads?
Post by: WB6BYU on June 21, 2012, 05:19:56 PM
Quote from: AE5X

I gotta say, the quad (2 el GemQuad) looks good compared to 3 and 4 element Yagis - lighter weight, smaller turn radius, equivalent gain and the ability to be WARC-capable simply by adding the wire...




The gain of a 2-element quad is less than a well-designed monoband 3-element yagi.
After making various compromises to get three bands on a yagi, it's a tossup, and
will depend on specific models and varies from band to band.

One problem with the quad is that the elements extend further below the boom, and
that needs to be considered when choosing your mast height if the tower is guyed
at the top (as should be the case with 25G.)  This also depends on the angle of your
guy wires.

Installing a 3-dimensional antenna is non-trivial, as WX7G commented.  Not that it
can't be done, but it may take more work.  (And you need space to assemble it on
the ground.)   You might check with the installer to see what his experience is in
this regard.

As far as reliability goes - ask around the the locals to see what their experience is
with quads holding up in the local wind conditions.


In the end it's your decision:  some choose one, some the other.  Certainly being able
to have gain and directivity on the WARC bands is an advantage.


Title: RE: Why so many more Yagis than quads?
Post by: K3VAT on June 21, 2012, 05:53:15 PM
Evening folks, ...

The tower will be a 50' Rohn 25 installed behind my garage and I have to decide what antenna goes atop it since the installer will be putting up the antenna as well as the tower.

A 20 ft turn radius is available - a sweetgum tree prevents more - that will accomodate the quad (easily), or a 3-4 element triband Yagi. It's a tough decision.  ... 73,  John AE5X

John,
Others have summarized the benefits of the yagi over the quad.  Even though you have limited air space you can put up a 5 band yagi (well, 3 elements on 10, 15, and 20 PLUS WARC Dipole).  One solution is the Mosley Mini33-AW (see: http://www.mosley-electronics.com/pages/amateur/mini33aw.htm (http://www.mosley-electronics.com/pages/amateur/mini33aw.htm)).  Mosley has been around a long time and these systems are time & performance proven (albeit at 500 watts max).  You'll see that the turning radius is less than 11 feet.  Don't let others dissuade you by saying that trap antennas are poor performers because traps are so lossy that they eat up all your power.  Modern traps used in Mosley, HyGain, Crushcraft for example exhibit very low loss (see the article on http://www.w8ji.com (http://www.w8ji.com) about trap performance).  Another shorty yagi is made by N6BT (founder of Force12 Antennas) - see Tom's website: N6BT.com.

50 feet of tower, (may be a couple more feet on your mast) will elevate these yagis up to a decent height whereby you will be able to work on world on these 5 bands.

GL, 73, Rich, K3VAT


Title: RE: Why so many more Yagis than quads?
Post by: WB6BYU on June 21, 2012, 09:58:02 PM
One thing I remembered about adding the WARC bands to the quad - it isn't as
easy as it might sound.

The problem is that, for example, while there isn't a lot of interaction between
the 20m and 15m elements, adding one in between for 17m causes complications.
The short of it is that the 15m reflector looks like a director on 17m, and the
17m reflector looks like a director on 20m.  So how does such an antenna
perform on bands where there are both a director and a reflector in the
same plane?

Here is one of the late W4RNL's article on the subject:

http://www.cebik.com/content/a10/quad/qab.html

He has a lot of other information on the website that may be useful.


Title: RE: Why so many more Yagis than quads?
Post by: STAYVERTICAL on June 21, 2012, 11:04:04 PM
Hi John,

If you can put up the yagi, I would go with that.
They perform well and have physical robustness which means less repairs, and tower climbing.
Quads perform really well, no doubt about that, but yagi's are just as good in practical terms.
I have tried a few quads, and they are great, but it becomes very frustrating managing the thing close to the ground.

If you want to dip your toe into the wire beam arena, perhaps a 5 band hexbeam would be a good interim experiment.
They work well, equivalent to a 2 element yagi, have a symetrical low wind load factor, are light, and inexpensive.

But if it were my choice, a 3 element or better yagi would be on my shopping list.

73 - Rob


Title: RE: Why so many more Yagis than quads?
Post by: AE5X on June 22, 2012, 05:31:00 AM
Thanks for all the comments guys - I appreciate it. A landline QSO with WG5G last night has me just about convinced to buy a Hazer for the tower. This would allow me to install an antenna at my leisure and to easily do work on it w/o having to climb the tower. It would also allow me to defer the antenna purchase since there would be no deadline for having it ready when the tower guy is here. (For those who don't know of WG5G, he has 340 confirmed with 5 watts/quad).

I just wish reviews of the 3 Hazer systems were more favorable...

John AE5X
http://www.ae5x.com/blog



Title: RE: Why so many more Yagis than quads?
Post by: WB2WIK on June 22, 2012, 09:28:41 AM
A Hazer with a quad might present more problems.

Rohn 25G obviously must be guyed, and the upper set of guys should be at the top of the tower, or very close to the top of the tower.  Since a quad extends as far below its mounting point as it does above, the quad will likely swing into the upper guy wires unless the mast above the Hazer mounted rotator is quite long, in which case it can exceed the design limits for the Hazer, even the galvanized steel one.

Some guys like the Hazer, but I always found them more trouble than not using them. ;)

To lower a Hazer on a guyed tower, step 1 is to disconnect the guy wire(s) that will be in the way of its coming down.  That's work, takes time, and should really only be done on a calm day or you risk the tower.

Step 2 is to lower the Hazer until the next set of guys, and then disconnect the guy wire(s) that will be in the way of its coming down.  Of course, this work is done at ground level (guy connection points with anchors), but it's still work and takes time, and a smart approach would be to re-connect the upper guy as soon as the Hazer is past it, so you're never left with two unguyed points at the same time.  A gust of wind could ruin your day like that.

For me, by the time I go through all the trouble of lowering a Hazer on a 50' guyed tower, I could have climbed the tower twice. :)

In any case, if you go with the Hazer system, I'd use a 2d beam design and keep the mast above the rotator fairly short, as they recommend.


Title: RE: Why so many more Yagis than quads?
Post by: NN4ZZ on June 22, 2012, 11:48:33 AM
If you really like Quads and want to see a solution to the 3 dimensional maintenance issue, you may be interested in this:

http://www.nn4zz.com/quadlock.htm

From NN4ZZ, the TiltPlate company.

Regards, Al / NN4ZZ


Title: RE: Why so many more Yagis than quads?
Post by: WA8UEG on June 22, 2012, 12:11:22 PM
Over the years I have used both, the quad as yielded much much better results then any 3 element beam I have had especially at mounting heights of 40 or 50 feet. Mine is very old, purchased in the 70's and has been used at several locations. Currently it has been up for about 8 years in the Pocono Mountains in Pennsylvania and has seen lots of wind and lots of ice and has handled it with no problem. One thing I would highly recommend is replacing whatever wire is supplied with copperweld. The copperweld will not stretch and will make a big difference keeping the spreaders from failing because of wind or ice acting as support wires for the spreaders. My 20/15/10 quad works well, in fact very well on 17 & 12 using the auto tuner on my FT1000MP. I have a MFJ998 legal limit auto tuner behind the amp if more power is required on those bands but seldom is except for "rare ones" where you would encounter pileups.


Title: RE: Why so many more Yagis than quads?
Post by: WA8UEG on June 22, 2012, 12:15:45 PM
If you really like Quads and want to see a solution to the 3 dimensional maintenance issue, you may be interested in this:

http://www.nn4zz.com/quadlock.htm

From NN4ZZ, the TiltPlate company.

Regards, Al / NN4ZZ

This is very handy for quads, mine has the Hy Gain boom to mast clamp that allows for tilting and is a huge help.


Title: RE: Why so many more Yagis than quads?
Post by: KE4VVF on June 22, 2012, 01:58:59 PM
Quads like to fall down.... go boom.
Mongo Like Yagi.



Seriously, I chose Yagi because they have higher wind /  ice survivability and generally require zero maintenance for at least a decade.  It's about as close to plug and play as you can get. 


Title: RE: Why so many more Yagis than quads?
Post by: WA8UEG on June 22, 2012, 02:29:47 PM
No pain....No gain ;)


Title: RE: Why so many more Yagis than quads?
Post by: W8GP on June 22, 2012, 03:45:11 PM
What about a log periodic? Gain is generally lower than a yagi, but still substantial compared to a dipole and the efficiency is much higher.Front to back is  very good as well. I've been using one for about 6 years and am more than pleased with it.


Title: RE: Why so many more Yagis than quads?
Post by: WA8UEG on June 22, 2012, 03:52:12 PM
What about a log periodic? Gain is generally lower than a yagi, but still substantial compared to a dipole and the efficiency is much higher.Front to back is  very good as well. I've been using one for about 6 years and am more than pleased with it.

Off topic but NICE shack.


Title: RE: Why so many more Yagis than quads?
Post by: W8GP on June 22, 2012, 07:05:20 PM
Thanks


Title: RE: Why so many more Yagis than quads?
Post by: K4RVN on June 23, 2012, 10:44:33 AM
Hello John,
I have owned 4 quads, the spider type such as the Gem Quad, and  Lightning Bolt, also Cubex boom type and homebrew quads of each type.
I just retired my 3 element 5 band quad  made from Cubex parts which had been in service with a Glen Martin Hazer. and Rohn 50 ft tower since 1989. I would offer the following suggestions to you:

1. Before buying a spider type quad such as the Gemquad, make sure it will work with the hazer for clearance to the tower. A boom type 2 element such as the Cubex will have an 8 ft boom which works with the hazer. I see that you have already bought the Glen Martin Hazer, good move.
2. Use a remote 5 band antenna switch with one feed line going to your tower and the switch, then use individual feed lines to each wire element of the quad. This way you will notice no interaction between bands although some is there it won't bother your signal so that you would know it. RG 8X is what I have used for years with good results.
3. Tie dacron sun resistant ropes to the hazer itself for guys on the tower. Once you have them adjusted, they simply come down with the hazer and nothing further is required. One set is fine for the 50 ft Rohn based on my experience. You will need to keep them fresh say replace after 10-12 years.
4. Take a look at the individual coax homebrew choke baluns used on each wire element by John Tait, EI7BA.
I found his method of feeding to be the best I had used over the years for long term service.
http://www.iol.ie/~bravo/Cubical%20Quad.htm
I modified my Hazer recently and have replaced my 3 element cubical quad with a 2 element hex beam broadband design of G3TXQ.  After owning and using the little 25 lb hex beam, I must say it has not been a let down after owning quads .
I have a photo of the hex with the hazer on QRZ.com
I recently gave my old quad well done and decided not to replace a spreader that I broke by being careless. Quads are great antennas .I have also owned trap yagis by Mosely, Hy Gain and others no longer with us. None performed as well as the 3 element quad at 50 ft.

Good Luck

Frank


Title: RE: Why so many more Yagis than quads?
Post by: WM9I on June 27, 2012, 12:43:50 PM
What about a log periodic? Gain is generally lower than a yagi, but still substantial compared to a dipole and the efficiency is much higher.Front to back is  very good as well. I've been using one for about 6 years and am more than pleased with it.

The LP may be to long for the air space he hase to work with.

Joe, WM9I


Title: RE: Why so many more Yagis than quads?
Post by: KE2TR on June 27, 2012, 09:14:49 PM
Hi John, I only owned one quad and too many yagi's to count threw over 44 years bein in the hobby but they do some nice things from what I could tell. In 2002 I tore down a station that had taken several years to build, stack monoband yagis's from 4 to 5 elements each on two crankups on a 1/3rd acre here in the burbs of LI, to say the least I keep one tower up until I sold the house and placed a Lightning bolt 2 element quad up. There was a huge difference from running a station that with 1500 watts into the antenna with a erp of 25KW to a lonely 2 element quad but the dam ugly antenna performed really well. It was up around 70ft and I could work the same long path opennings on 20 that the 4 element yagi's could but intead of 59+10-20 over I was 59 and maybe at times 5 over but the noise level was much better with the quad over the yagi, that also could be thye 4el monobander had more gain. Unless you go for the Stepper  3el yagi there are not thyat many tribanders that will touch a well built quad, F12 had some nice antennas that I woned in the past the like the stepper the prices went threw the roof. If you are into building there is a new guy with a pop up add on QTH, he's out in Ohio and builds a real nice spreader hub that will give you proper spaceing on 20,17,15,12,10, then you couold either use a 100>50 ohm balun for a simple feed system, I dont recall but he may provide spreaders and the wire hangers as well. Using the right fiberglass spreaders will give you years of durability and the gain is slighly less than a 3 el monoband beam but since its elements are both vertical and horizontal you seem to get less signal fade( the simple quad heard more like a small stack than an antenna just at 70ft. Max FB is not as good as a monoband neam but its around 20db which isny bad. When we move again I hope to put back another tower and its either gonna be a stack of F12 C3's or maybe a stack of quads, that last one would look like the russian embessy but I bet they would be smookin hot. If you have your quad were the boom is at 52ft your top part of the element is at 60ft and the bottom is at 44ft(horizontal section) so now you star to see how they are designed to hear real well cause you covering different angle hights with a single antenna.
Jim


Title: RE: Why so many more Yagis than quads?
Post by: WB4CMB on June 27, 2012, 09:54:41 PM
Greets Fm CO
     I am an old ham trying to get back in ham radio after a long time except for a few squirts.  I have built 3 quads and several dipoles/inverted vee's.  I've never owned a commercial antenna.  Right now I need to decide on which antenna and get an antenna permit.  You can see my post on eham or QRZ, "Visit To Permit Folks"
Looks like I am limited to 35 ft max height.  Also, must get a CO PE's approval of both tower and antenna.  There is a 100 mph for a 3 second gust requirement.  My preferences right now are for a Glen Martin roof tower and either a quad or spiderbeam.  A firm "MaxGain" has fiberglass that is .125 wall thickness, that should help the strength angle.  Any helpful hints?    Thanks   Ray


Title: RE: Why so many more Yagis than quads?
Post by: K4RVN on June 29, 2012, 05:54:20 AM
You might want to take a look at a broadband hex beam. I just retired my 3 element 5 band quad and put up a 5 band hex beam. It only weighs 25 lbs and works well at low heights on a push up mast so they say. I have talked to quite a few using 30 ft on a push up mast. I have been very pleased with my hex beam after using quads for over 25 years.
A smaller rotator also does the job, one feed line for all 5 bands. I use 100ft RG8x running an amp which is not that expensive and does the job.
The hex is a two element beam in case you are not familiar with it.

Frank


Title: RE: Why so many more Yagis than quads?
Post by: KU7I on June 29, 2012, 10:21:34 PM
A 5 band hexbeam is a good lightweight option. I have put up and used several quad antennas from single element to four elements. I have also used and put up yagis. The hexbeam reviews all say the same thing: hexbeams work well. The quad works very well once you get it up at least 25 feet or higher. Although it is heavy the force 12 XR-5 (5 band, 2 ele yagi on 18 ft boom) is mindlblowingly good. If you are a bit older and the physical limitiations could be a factor go for the hexbeam on a 35 foot pushup pole and guy it. Put the rotor at the bottom and you are done. Plenty of internet articles on this method. Good luck. Lane Ku7i


Title: RE: Why so many more Yagis than quads?
Post by: K7LA on July 01, 2012, 12:47:53 PM
Some good comments have been posted.  The overwhelming majority of the time a good yagi is your best option on a tower.  The quad does have one advantage over the yagi at very high altitude (ex. extreme mountaintops) in that the quad is subject to less corona effect.  Unless you are working from the Andes or Rocky Mountains, I agree with most posters that the yagi is the ticket.  7 3.


Title: RE: Why so many more Yagis than quads?
Post by: PA1ZP on July 01, 2012, 02:39:48 PM
Hi All

A yagi especialy a plumbers delight with gamma match is very easy to build mechanicle talking.
It is easyer to build a yagi that will last for many years.
A Yagi has a bigger bandwith to a quad.
A quad needs isolating spacers etc and is bigger and less easy installed in a mast.

But since a few years with prices and availability of very good quality and relative cheap fiberglass rods quad design and multiband wire beams like the hex beam or spider beam are much more sold, and they are very often used in easely erected portable stations.

For what log periodics is concerned, they are big bulky and the gain is not as high as good build multyband yagi's certanly the developement of yagi,s like the StepIR make use of log periodic beams not logic anymore in amateur radio.
Log periodics are still in use by a lot of embassies in a lot of countries, as back up for satelite use or use in recieving stations for official use.

But with bamboo or fiberglass insulators and spacers a quad or muliband quad is still a good and cheap choise or alternative to the yagi antenna.
I think  that with good designs and smart use of software modeling the quad antenna still will be a good and decent honnest antenna that will never be forgotten as a good and nice alternative to the yagi.

One of the finest examples of modern design and use of modern materials and computer controlled directing of satelite systems are the multi element loop yagi's designed by PA5RWE for use in satelite traffic on 145 and 440 MHz.
These antennas with their rotatable back ends worked extremely well in use in satelite traffic. and in use for DX on VHF/UHF mobile traffic and DX s all polarisations like vertical/horizontal and even diagonal could be done with these lovely designed loop-yagis

It is very sad to know that Chris PA5RWE passed away a month ago at the age of 51
He will always be rememberd as the coinventor of "de draaikont antenne" the turning back end (Butt) antenna.

One of his last very memorable contacts was with PI9ISS with cosmonaut Andre Kuipers on board on ISS this contact was broadcasted a day later on national radio here in PA, with a nice interview with Chris PA5RWE.   
He also made a lot of contacts with the Russian spacestation MIR using his unique but  small antenna set-up       


Title: RE: Why so many more Yagis than quads?
Post by: K5KNE on July 04, 2012, 07:24:46 PM
Quads are really very good antennas and I thought that I picked up less noise on them. I made one years ago and it really worked well. I moved several times and had it configured to only 10 meters finally. Today, I use a tri-bander yagi

The 20 meter quad is a very large antenna. It is a challenge to put together and put up on a tower. It is not a very pretty sight to the neighbors either. But, 15 and 10 meter loops can be inside the 20 meter loops.

I think tuning a quad to frequency is more difficult that a yagi. Also, if you have other antennas on the tower, - the quad monopolizes the top area of the tower.  You can put a vertical, say for 2 meters, sticking thru the top of the quad, but if you want to make lower band inverted vee antennas out of the guy wires - they have to attach to the tower well below the quad - say 10' below the top.

Commercial quads are good and you would like one. A yagi is a lot easier to put toether and get in place on the tower. Yagis are almost maintenance free and last for years.
Good luck on finding the right antenna for you.

73  Walter K5KNE



Title: RE: Why so many more Yagis than quads?
Post by: KU7I on July 05, 2012, 06:30:55 PM
I have built around six rotatable hf quads and delta loop arrays in the past 20 years. One that I built about ten years was constructed from parts obtained exclusively from Home Depot except for the boom. I made the spreaders out of aluminum tubing that they used to sell. Not sure if they still sell it but I also learned that Lowe's and Home Depot carry virtually the same exact inventory of "stuff", most of it the same manufacturer. The spreaders were a combo of this aluminum tubing and pvc.

I have a bunch of pics of the last one I built which was a three element rotable delta loop parasitic array for 20-17 and 15 meters. Each driver was fed with 300 ohm tv type twin lead and had a dedicated Heathkit SA-2040 2kw tuner inside the shack. It was a blast to build and learn from. If I could find a way to put the pics somewhere on the internet it would be cool or if someone here can store them I can provide the pics. I have a bunch...maybe 30 in total and the pics give a lot of detail. Also, I found the quad/delta loops to be a bit quieter on receive, sometimes by several s units depending on the type of noise. Lane Ku7i