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Well, it is supposed to be nice this week, so I will try it and see what happens. Hopefully it won't be a tropo day.
 

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The more I think about this and the more I read about results of those who tried stacking, I'd venture stacking vertically rather than ganging horizontally will produce disappointing results for the most part.

The chances of the signal strength being even on both antennas stacked are probably slim.

Next year I will try a horizontal gang of my XGs and see what happens.
 

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Modeling the swept reflectors on it would be very tedious.
If youre going to sweep the directors, then you should also sweep the driven element for effect. At most, I think all that work is going to get you another 1 db max, mostly for the higher channels and maybe at the expense of the lower channels.
 

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Vertical or Horizontal stacking, you still need to find that magic height, heh.
 

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Hmmm. I don't want to lose the lower channels. Since its easy on my test tripod, I'll try just the directors first and then the element.
 

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come on peano, why not try it now, theres still time, still no snow! ;)

BTw, so far im having better results with the yagis horizontally stacked...


in my location my signal is between 9 to 12 ft a/g, anything higher or lower cause a fairly rapid drop out...thus it is ILLOGICAL to put a vertical stack as no matter where you place it, one or the other antenna is not doing anything, and probably hindering ( I only realized this after reading here and there, and after I dismantled my horizontal gang...:mad:
 

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I have also wanted to try this too, but I have 1/2"X1/2" wire mesh that I was going to try, but noticed that you used 1x2 mesh instead for 1/2" x 2 spacing.

Do you think that I would be better off with 1/2" x 1/2" reflector spacing or 1/2 x 2 inch? I can always modify the existing mesh by cutting out the wires, but I wouldn't want to have to put them back if I made things worse. ;)

I have spent a lot of time fine tuning my location on top of a shed with mixed results and I really don't want to spend to much more time experimenting with the weather getting worse. I would like to do what I can with what I have before getting another 91XG to stack with this one and find out it doesn't work any better since I can only move a few inches in any direction with adverse results.

The channels I am trying to lock in on, are 2edge, and in the low UHF 38 and 39. They come in worse than 48, which is very good, and all are from the same location.

Thanks in advance. and any suggestions would be appreciated.
 

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Try your 1/2" by 1/2". Don't cut the existing mesh! I just tie wrapped the extra piece onto the exisiting mesh when I did it.


Let us know your results.
 

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OK, I will try to check it this weekend if the weather cooperates. We are expecting some heavy rain in our area so we will see. I tie wrapped the mesh to the reflectors too. I used about 24" wide by 18 high on each and left the gap, instead of using just one piece of mesh.

I have to take it back up and find the sweet spot again. I will let you know what happens. Unfortunately I am also trying a coax-loop balun too, so it won't be an ideal test, Thanks,
 

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Well, I can't say how much improvement I had but there was some. I am just not sure yet if it was the balun or reflectors. When I first set up the antenna I had it at the peak of the shed and it was pulling in the three channels at one point with about 40% signal strength on each of digital 38, 39, and 48, however as the day went on 39 disappeared like it usually does. I am guessing I am dealing more with signal availability as opposed to low signal strength.
 

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With the cold weather approaching fast and tropo finished for the most part, I decided to finally try stacking my 91XGs atop my tower.
I did the same and a bit more. My main goal was to get better reception on Channel RF 50.

I first stacked a pair of Winegard 9032s, then ganged side-by-side. No gain.
Also tried flipping baluns. Note that although reception got slightly worse with one mode, it was not a whopping difference. Certainly did NOT loose all siganls because of one out-of-phase.

I then stacked a pair of 91XGs and no gain and if anything, worse then one alone. Then ganged , side by side and DID get a slight overall gain - enough to make a consistent difference. That was on a metal crossbeam made from 1 1/4" galvanized EMT pipe. Problem was . . . those dinky little 10/24 bolts the 91XG has on its mount are too small to keep it tight in high wind when mounted this way. I then made a wood horizontal crossbeam with a vertical short mast on each end, and it worked better. Better gain and holds in high winds. Yeah, I know wood is frowned upon by some - but don't complain to me. I'd prefer a fiberglass pole but didn't have any laying around. Used a tight-grain, pressure-treated piece of southern yellow pine and it will last longer then I will. More wind resistance then I'd like, though.

I'm in an extreme-fringe area with lots of multipath signals. I tested the antennas at various spacings. I found that best spacing was channel dependent. Finally used some computer modelling software that gives me spacing by the channel. Used the recommendation, and it's working a bit better then just one antenna. Not by much, but enough to make a nice difference.

By the way, with all attempts, I tested each antenna by itself before doing anything elsel

When I got all done, I've got the pair of 91XGs on top, with a two VHF antennas below. All into one coax. 91XGs joined by a diplexer with equal-length coax - then on to a UHF/VHF combiner. The two VHF antennas are joined by a low-high VHF combiner.

I'll be adding another pair of UHF antennas later to point in a different direction for channel RF 26. I'm going to use a narror channel filter to join them into the rest.

One of the photos shows my first installation that didn't hold in high-wind and shows one 91XG pointing up to the moon.

Stacking/ganging distance for 2 Yagis with 93” booms at RF 50 (91XGs)

31.9" (2' 7-7/8") Horizontally
30.9" (2' 6-61/64") Vertically

Stacking/ganging distance for 2 Yagis with 93” booms at RF 26 (91XGs)

36.6" (3' 0-5/8") Horizontally
35.3" (2' 11-11/32") Vertically






 

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Anyone want an 91XG?

I installed a 91xg this past weekend to try to pull in some distance buffalo stations but got only marginally better results than my current 4221. I going to try a pre-amp and combining it with my 4221. If this doesn't improve results I may end up parting with it. Let me know if anyone is interested in it.
Thanks.
 

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Nice setup! Where are you located? And you say you used a diplexer to combine the two 91XGs?
I'm in Otsego County, New York. I used a Winegard antenna coupler # CC-7870 which is basically just a diplexer put into a weatherproof plastic box along with a mast-mount. I tested it with a vaious brand diplexers also and they all worked basically the same. None worse and none better.
 

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When I got all done, I've got the pair of 91XGs on top, with a two VHF antennas

I agree it is a nice setup. I was wondering how much higher your 2 91XGs are above the 2 VHF antennas?

I tried putting my 91XG above my VHF antenna and hardly got anything. When I pulled it down and moved it about 8 feet to the side at about the same height as the VHF antenna it did much better.
 

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I agree it is a nice setup. I was wondering how much higher your 2 91XGs are above the 2 VHF antennas?

I tried putting my 91XG above my VHF antenna and hardly got anything. When I pulled it down and moved it about 8 feet to the side at about the same height as the VHF antenna it did much better.
I tested each antenna on that mast by itself and then with the others with various spacings. I wanted to make sure I didn't "rob Peter to pay Paul" while adding antennas. I did not detect any difference on any antenna as long as spaced two feet apart. That's the vertical boom to boom distance. I wanted to space then as close as possible to leave more room on that mast in case I added more antennas later. So, I don't know what to tell you. Most what you read will warn you to have at least 4 feet. With my stuff? I've got two multi-antenna installations and on each, two feet has been fine.
My other install has a DB8 sitting over a Wade VIP-307. That being said, I have them all spaced at 3 feet right now, because I don't need the extra room on the mast.

I went up and added a fifth antenna a few days ago and it worked awful. I was dead-sure the problem was too many antennas too close together. So I moved all the others out of the way and guess what? That damn antenna still didn't work well. It's a Winegard 9032 UHF corner-reflector Yagi and it's the only antenna I feel I've got a legitimate complaint about. It was recommended to me by two TV broadcast engineers. They both claimed it is the highest gain UHF antenna for my area, so I decided to try it - regardless of what I've read elseswhere. It works a little worse then the 91XG and DB8 for higher channels. But, on 26 to 30 it is useless. And, I have three of them here - now just taking up storage space. It's bigger then the 91XG, but I guess big isn't always good.

One thing I did notice though. If you take two 91XGs, stacked vertically, and move one forward about a foot, reception spikes up quite a bit. I tested this just holding by hand. I wasn't about to try to make a mount though, to hold them that way.
 

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jdemaris,

If you take two 91XGs, stacked vertically, and move one forward about a foot, reception spikes up quite a bit. I tested this just holding by hand. I wasn't about to try to make a mount though, to hold them that way
Thats the one configuration I havent tried, yet, I always wondered about that, I read about the math behind it somewhere, its quite something!

I was too "discouraged" to try to actually set this up...think it should be modeled first!
 

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jdemaris,
Thats the one configuration I havent tried, yet, I always wondered about that, I read about the math behind it somewhere, its quite something!

I was too "discouraged" to try to actually set this up...think it should be modeled first!
Well, overall . . . I find setting up dual antennas to be kind of depressing. My first try was with those two Winegard 9032s. I tried every just about every configuration and no matter what I did, I couldn't not get two antennas to work as well as one.

With the 91XGs things went better. With vertical stacking, things went the same as with the 9032s. 1 plus 1 equaled less then 1. But, with ganging I actual got some wierd gain and 1 plus 1 equaled maybe 2.2?. It doesn't show much on the signal meter but provides me a more consistent signal on my problem channel. Also, as a side benefit, I'm getting another UHF channel that I'm not pointed at. As I understand it, that is NOT supposed to happen with ganging two antennas. Regardless - one 91XG pointed at 200 degrees (for channel 50) does not get me RF 26 that ought to be at 100 degrees. But, with the two ganged, we now get it most of the time. Weird. Obviously, with all the multipath signals snaking around here, I'm not sure where that RF 26 is actually coming from - as far as the compass goes. I do know that one 91XG does not get it, and two do. It was this "new discovery" that led me to wanting to install yet another antenna pointed in the best direction for that channel 26. But, when I installed the single Winegard 9032, I could not get 26 at all -regardless of where I pointed it. So, if I ever do add an antenna for just 26, I guess it's going to be another 91XG or a DB8 (which I am very impressed with). I just with I could find a use for these Winegard 9032s. Well built, big, and nice looking antennas that seem to be pretty useless.
 

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Well built, big, and nice looking antennas that seem to be pretty useless.

Maybe the balun is bad? have you thought about making up a coax balun for it?

Also when you tried stacking the two 91XG antennas vertically which one was ahead of the other, and do you think the signal was better than what you have now horizontally? I don't remember seeing anything about this except for the CM 4228 antennas.

I also have a problem group of channels and am also extreme deep fringe, and I am thinking of stacking but need to finish up more testing with an added mesh and coax-balun I added to my 91XG, but the weather is keeping me off the wet metal roof with the ladder. That takes the fun our of testing.
 

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jdemaris,

Yep, my testing showed that my 2 yagis gagned at about 35" was better than anything else, including stacking. It only provided a more stable reception though. I too had an odd occurence whereby when I aimed off my desired channel, reception improved even more on that channel (counterintuitive, but anything is possible)
 
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