But they look so much cooler
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quad reflector versus yagi reflector
- Thread starter smokercraft
- Start date
Quads do look cool but I can see there just a mess to work with.But they look so much cooler
My Bambi is a pain to put up sometimes.
HUH? Are you implying that I'm wrong?
Now remember, unless I'm mistaken, I'm never wrong!
...once I thought I was wrong but I was mistaken.
Well, first, the difference between Quads and Yagis is considerable. A Quad will out-hear & out-talk a Yagi of a greater number of elements, and the Quad will be quieter, is what I've noted from experience, over & over again.
One important factor is using one. There's a plethora of numbers, models & other half-baked hoopla designed to show how a closed-loop, full-wave wire element Quad isn't really much different from a 1/2 wave, open ended Yagi.
- Pay attention to them and leave the high-performing antennas to others, or ignore the nay-sayers and come on in to the wonderful world of quiet and powerful directional antennas.
Also, if you design & build a dual-polarization Quad in the Square, not the diamond configuration - it will only take up 1/4 the dimension of a Dual-Polarization Yagi.
- Quad = 9' x 9'
- Yagi = 18' x 18'
...and you'ze guyz say a Quad is hard to work with? LoL.
The Quad will hear and be heard earlier into opening DX conditions and hang in there longer than a Yagi. Happened all the time for me & Ed, for whom I built a 5 el Quad.
The Quad at 36' will provide incredible performance, a Yagi at 36' - not bad.
If you're worried about strength & longevity then use stranded wire not solid, and pre-stress the fiberglass spreaders with Dacron covered Kevlar line. That stuff is unbelievably durable & strong. Just use the kite string size and expect it to last 15-20 years. That will take up the stress so the wire can just hang there with no real pull or torque on it.
Also, use that semi-flexible CA glue/epoxy at the point where the wire meets the spreaders and build it up a bit to act as strain-relief - out about 1/2" - 3/4" from the spreader onto the wire.
The real secret is in the tuning. It's important to have the driven cut correctly & matched well for lowest SWR/reactance, but equally important, if not even MORE SO, to have the reflector dialed in, not just ballpark close - like most quads come out of the box.
You simply won't believe what you hear & the improvement in TX over that "other" antenna - IF the Quad is built & tuned properly.
I say "not necessarily true", and you go straight to assuming that I was implying that you were absolutely positively wrong? The concept you used, was sound only as long as there were no other aspects caused by two different antenna designs might play a part. All I was saying was that there were other factors in play between two antennas of different designs, factors that, based on your wording, you didn't even consider. Do you even realize what it is I was referring to when I said that? I talked about it above.
I am happy to make some models for you when I get a chance, perhaps in the next few days. In my experience Captain Kilowatt is correct.
In general, while perfectly happy using either, I personally prefer the quad antennas, although for generally different reasons than Needle Bender. That being said, those aren't always the best options for everyone.
I will also offer some advice. In most cases the antennas in question as well as what it takes to mount them properly have a certain amount of expense to them, be sure that the antenna you get will make you happy not the guy that will tell you to buy the one that they like and no other. Both of these antennas, configured properly, will perform about the same. Both of these antennas will have different strengths and weaknesses. Both of these antenna designs are good designs. In the end, your best bet is to ask the right questions.
Fun fact, quad beam antennas are never tuned to have their maximum gain point in the center of the band of frequencies you intend to use it in, bonus points to the person that can explain the two reasons why that is...
The DB
Don't you mean "mistaken"?
- No I was just being facetious, didn't mean for you to take it seriously, needed a smilie, but I forgot to add one. NP.This is one of those debates which can really only be answered by the person choosing & using the beam, which ever type is decided upon.
I already know which I prefer from years of outperforming the local Yagi guys.
Interesting thread though!
73
NB, I appreciate the humor, but I think you've used that line before. That said I do have some questions though (in bold type) and maybe a request or two.
It is true all beams need to be tuned and/or adjusted in order to produce the characteristics desired for match, gain, and back and/or side rejection and this is not a secret or a mystery. There is also a more recent scheme that produces a so called optimized configurations. Personally, you'll note I tend to use a balanced design idea.
What did you use to generate your design dimensions?
I've found several calculators that did not produce similar results when I entered in the same dimensions for my 4 element horizontal quad design, the one I posted the other day here is this thread. I will post the link below.
Click here: Quad reflector versus yagi reflector
Your reports of open and closing the band are surely obvious, it does happen, but how do you tell it is not just a lull with the conditions stretching out the band. If you turn on your radio and there is no traffic to start and you wait a while and you are then able to hear somebody making a call, does that make you the first. Is this what you call opening the band, and similarly at closing making the last contact you hear?
Does the guy on the other end of the contact also have to have a quad?
If so, how do you know that?
A long time ago I produced some rather poorly done videos of some of my radio contacts, and when I posted them on the forum and guys were able to see what I was doing...I was soundly critized for the way I compared signals, and I was primarily doing only local contacts that I knew where and what they ran for an antenna. I did make an occasional DX contact however and you would have thought I had done a cardinal sin.
Now in the report above that Wavrider posted, we have an experienced radio operator with some fame going around the country with a mobile Yagi setup he could raise and making comparisons with folks he visited that had Quad antennas. According to his report he was doing long haul comparisons and I don't hear any uproar about him doing something similar to what I had done. Maybe the difference in part was I only did RX signals in my reports, and only occasionally did I get TX reports.
Do you think I got the where-what-for simply because I was comparing CB antennas?
How do you tell for sure what allows you to communicate while another guy in your area cannot?
I've experienced something similar many times, but I never attributed it to my antenna per se...I always considered it due to the environment and/or some other unknown conditions at the time. It would seem pretty presumptuous to think my antenna was the only difference if that happened to me.
I believe you really may have experienced the other issues you noted in your post about the Quad, like the antenna being very quiet. But, IMO having a lossy setup or and an old somewhat deteriorated feed line can also produce seeming quiet working receive, and still allow you to TX successfully...if conditions are favorable.
I have a CB buddy that worked a Starduster antenna up very high...maybe 60' feet. It was old, but still worked for him. Another buddy came by his house one day and told him his feed line looked like it was just hanging loose at a tie strap holding the line to the mast at about 30' feet high up. Chucky Boy was talking on his feed line, and did not even realize it, and he never missed a contact as far as all of us other buddies around him could tell. I was close enough that he splattered RF on my station across the CB bandwidth too.
I have a 100' foot RG8x feed line with a clear coat cover I got from a buddy that ran an A99 with it for over 10 years. I worked that line until a local buddy convinced me I was not showing him any signal...even though I was talking to the same contacts as he was on his 5/8 wave JoGunn. I took the antenna down and I could easily see what looked like black mildew areas up and down the entire length of that line.
I checked the through put with an inline meter and a dummy load with 100 watts input...I saw only 10 watts at the other end, but I was still talking and just a fluke brought that to my attention. My SWR was also flat from Ahole to appetite and that didn't alert me either, these were surely signs of something going on that I did not understand at the time.
How do we really determine why and how these radio signals respond like we see them do some times?
Do you have a test you run that produces such results that tells you what you claim here?
How do you know you are really opening up the band?
Again, what Quad calculator did you use to get the dimensions for the Quad you talked about building for a buddy above?
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Were going to be moving to Kalispell,Mt. in a few months. With that in mind, and maintenance details I think the Yagi will be best for my install. I will most likey set up a 2el or maybe 3el Quad as well to "play" with, then take down in the winter months.
Thank you for the input and help. I will keep reading and learning.
Thank you for the input and help. I will keep reading and learning.
Agree , with a caveat concerning height vs freq wave length .
at lower height/wl ratios, the quad does have better performance.
Yes it does and that better performance is also minimal and not like the difference between daylight and dark.
Quad is indeed an good antenna
The best thing about a quad is it looks like a monster antenna only two elements
compared to a two element yagi, looks puny and small.
I like a quad, but I rarely if ever see any performance difference between a quad and yagi.
The quad is a little more quiet due to the closed loop construction, and maybe just maybe the quad reduces fading on DX signals due to having elements in both planes, Vertical and horizontal.
The best thing about a quad is it looks like a monster antenna only two elements
compared to a two element yagi, looks puny and small.
I like a quad, but I rarely if ever see any performance difference between a quad and yagi.
The quad is a little more quiet due to the closed loop construction, and maybe just maybe the quad reduces fading on DX signals due to having elements in both planes, Vertical and horizontal.
[QUOTE="
Fun fact, quad beam antennas are never tuned to have their maximum gain point in the center of the band of frequencies you intend to use it in, bonus points to the person that can explain the two reasons why that is...
The DB[/QUOTE]
HMMM, perhaps the quad has mostly uniform gain across the useable bandwidth
unlike a yagi that looses efficiency the further away from design frequency ?
Just pulling answers out of the air cause I dunno why?
Also BTW some quad builders say use 4% larger for reflector, and 4% smaller for each director instead of the usual 5%.
Goes right along with if you using insulated wire the measurements should be 4% smaller in length due to velocity factor of insulated wire.
The quads I have built tuned easy, worked OK, can not say they were perfectly adjusted for efficiency at the frequency of design, I built them, tuned them, installed them and made contacts, they worked, But nothing to convince me to say a quad is better than a yagi.
Fun fact, quad beam antennas are never tuned to have their maximum gain point in the center of the band of frequencies you intend to use it in, bonus points to the person that can explain the two reasons why that is...
The DB[/QUOTE]
HMMM, perhaps the quad has mostly uniform gain across the useable bandwidth
unlike a yagi that looses efficiency the further away from design frequency ?
Just pulling answers out of the air cause I dunno why?
Also BTW some quad builders say use 4% larger for reflector, and 4% smaller for each director instead of the usual 5%.
Goes right along with if you using insulated wire the measurements should be 4% smaller in length due to velocity factor of insulated wire.
The quads I have built tuned easy, worked OK, can not say they were perfectly adjusted for efficiency at the frequency of design, I built them, tuned them, installed them and made contacts, they worked, But nothing to convince me to say a quad is better than a yagi.
Efficiency, that is something I haven't looked at across the bandwidth.
This gain data across frequencies is something I actually once confirmed using a field strength meter, and a home made 2-meter 5 element quad.
Both of these are from the same model, a four element quad tuned for peak gain at 27.2 MHz, and it is one wavelength high (about 36 feet) over average ground.
What happens when you get a little higher than said frequency? Less than 1 MHz away (in this case 0.8) from that point we have almost a 10 dB drop in peak gain. At that point an omni mounted at the same height would generally provide better gain than the quad.
The other reason is easily shown with this data here, an SWR plot over the same range of frequencies.
This is from the same model above, and we see a low and stable SWR area, pretty much from 25.8 MHz to 26.8 MHz, and it is easy to tune for, and it is possible to adjust this range to have an even lower natural SWR and be more broad banded as well, however, in that short distance between the range and peak gain we are already at 10 to 1 SWR, and it continues to spike up quickly past that point.
And for anyone who is curious, resonance is actually at 26.4 MHz, which is on the lower half of the low SWR range fairly close to the middle, which I guess is pretty close to where we would expect to see it.
The DB
I'm just guessing too wavrider. I prefer to look to my modeling to check things out, if I can.
My only real world experience with a quad was a two element on a 50' foot crank up, and best I remember I had trouble with tuning it, so I worked it through a tuner and it did fine. It did seem to improve contacts sometimes vs my old CLR2 back then, and sometimes I realized some rejection off the sides and back. I was not impressed...but I didn't realize at the time that tuning was absolutely essential for the antenna to work efficiently. I knew nothing about efficiency and even after I read up about it...I still did not know how to measure such a characteristic. I use to ask my antenna mentor about efficiency and all he would say is: "...you can't measure efficiency...but you can get some ideas about your antenna effectiveness."
My Quad models were generated using http://calc.n6ach.com/quad.html calculator. I get wire length ratios about 2.8 - 3% and it uses a balance boom distribution scheme for the spacing. This balanced boom idea may be what helps the model to show very little mismatch.
Your description does not surprise me, but I did find the only Quad I ever had, a 2 element needing a matching system of some sort. I just used a tuner instead of a matcher and it worked fine for what it was, but I was never really impressed even when compared to my old CLR2 back it those days.
I don't see any of these Quad beams showing much, if any, real bandwidth and that does not sound efficient for an antenna to me.
My 4 element model I posted earlier shows only 0.50 MHz bandwidth, and that is really small. The CB band is about the same size from channel 1 through 40.
So, IHMO you're not going to be working very far from resonance using a Quad...unless maybe you add a lossy matching system and then detune the antenna to get back to a match. That might add some bandwidth.
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Thanks for replies DB and Marconi.
Interesting on the VSWR bandwidth VS gain and if I read the post correctly. 27.2 was design freq and resonance was 26.4? Not surprising, so much wire in near vicinity so mutual coupling is inevitable.
Some of the old QST magazines and other articles show quads being built using wooden booms and wooden dowel rods, other show using PVC plastics. they may be on to using non inductive type material for constructing the quads.
I have talked with several quad users, The VK stations on 17 meters have some big signals using multi element quads.
The missionaries in S. America like 15 meters for running phone patches and they are using quads with bamboo spreaders. ( Use what ever is available for constructing an antenna in the jungle)
I have tried the 75 ohm coax, for matching, it works, very narrow bandwidth.
It is said a four element direct feed with proper spacing can have a decent input impedance but has around a 500KC bandwidth, some say a narrow bandwidth means a high efficiency, dunno to that one.
Best I ever did was make one leg of the driven element of the quad out of aluminum tubing, add a gamma and tune it where you need it, worked great, fantastic bandwidth. Easy to tune.
Interesting on the VSWR bandwidth VS gain and if I read the post correctly. 27.2 was design freq and resonance was 26.4? Not surprising, so much wire in near vicinity so mutual coupling is inevitable.
Some of the old QST magazines and other articles show quads being built using wooden booms and wooden dowel rods, other show using PVC plastics. they may be on to using non inductive type material for constructing the quads.
I have talked with several quad users, The VK stations on 17 meters have some big signals using multi element quads.
The missionaries in S. America like 15 meters for running phone patches and they are using quads with bamboo spreaders. ( Use what ever is available for constructing an antenna in the jungle)
I have tried the 75 ohm coax, for matching, it works, very narrow bandwidth.
It is said a four element direct feed with proper spacing can have a decent input impedance but has around a 500KC bandwidth, some say a narrow bandwidth means a high efficiency, dunno to that one.
Best I ever did was make one leg of the driven element of the quad out of aluminum tubing, add a gamma and tune it where you need it, worked great, fantastic bandwidth. Easy to tune.
What did you use to generate your design dimensions?
Oh, I just use an SWR meter & an S-meter to tune. Start with the Driven, make it's length 1005/freq in MHz and cut until lowest (2:1) on the SWR meter.
Add Reflector (1030) & cut until max F-B is attained using a beacon & S-meter.
Add 1st Director (985), tune the same way as the Reflector.
Add additional Directors & tune the same, one @ time.
Does the guy on the other end of the contact also have to have a quad?
Nope
Do you think I got the where-what-for simply because I was comparing CB antennas?
I'd have to see the video. I can't respect any comparison not done on same mast, coax, too many variables at even merely 6'-8' away.
How do you tell for sure what allows you to communicate while several other guys in your area cannot?
Typical, repeating experiences over months/years.
Do you have a test you run that produces such results that tells you what you claim here?
No, that was at my QTH of 28 years, I pretty much knew what and who did what.
How do you know you are really opening up the band?
I could hear the clicks and snaps as I twisted off the top.
Again, what Quad calculator did you use to get the dimensions for the Quad you talked about building for a buddy above?
Again, Reflector-1030/freq in MHz, Driven-1005/freq in MHz, Directors-985/freq in MHz for starters.