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Author Topic: Why so many more Yagis than quads?  (Read 6279 times)
W8GP
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Posts: 206




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« Reply #15 on: June 22, 2012, 07:05:20 PM »

Thanks
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K4RVN
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Posts: 769




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« Reply #16 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
« Last Edit: June 23, 2012, 11:04:41 AM by K4RVN » Logged
WM9I
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Posts: 8




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« Reply #17 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
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KE2TR
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Posts: 154




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« Reply #18 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
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WB4CMB
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Posts: 39




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« Reply #19 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
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K4RVN
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Posts: 769




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« Reply #20 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
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KU7I
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Posts: 122




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« Reply #21 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
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K7LA
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Posts: 62


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« Reply #22 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.
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PA1ZP
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Posts: 236




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« Reply #23 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       
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K5KNE
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Posts: 65




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« Reply #24 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

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KU7I
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Posts: 122




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« Reply #25 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
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