goforit,

Thanks for that link.

Before reading that post, last night I went up to the roof and pulled the black caps off my antenna. It actually made things worse, I think. I was getting WIVB in dribs and drabs before the procedure, then nothing at all since removing the caps. I suspect that I may have changed my aiming a bit, though.

I'll review that link and mess with it some more.

Thanks again.

Yep, antenna-sharing is only allowed in MATV systems and not "over the fence". Understandably it is a touchy subject with the cable companies. :)

cogitech's discussion has switched to his own reception expectations so several posts have been moved to this thread:

ON - City of Toronto Metro Area <OUTDOOR Antennas Only> - OTA (http://www.digitalhome.ca/forum/showthread.php?t=42423)(Post #1102)

This keeps the current thread focused on the actual stacking and ganging of antennas.

cheers

To stack, or not to stack? That is the question.

SO my dad finally went out and got 2 4221HDs (finally, he made the right decision!)

I know I keep changing my ideas for my future setup (i flip flopped between 4221HD/building a GH which I still plan to do for kicks)

But now that we have 2 antennas, his original intention was to aim one at TO, and one at BUF.

Instead, I have a good feeling that stacking would be a better idea.

I just have a few questions.

1. Is stacking worth it? Or will the combined losses of the 2 PCT baluns (plus 2x 5ft RG6) just cancel the potential 2.5db benefit?

2. I'm gonna grab myself a CM3212 splitter to join the two. Now Saveandreplay has 2 versions of the 3212, one that goes for $2, and one that goes for $6. What's the difference between the two, and which one should I get? And are there any losses associated with the splitter used in reverse?

3. I might aim the remaining antenna (our current clone) at CKVR to get a watchable picture, then combine the two using the 7777's seperate VHF and UHF inputs. Using a 4bay clone I know is not ideal for VHF, but it works for me anyways. Do the regular antenna seperation rules still apply, or does it not matter seeing as the UHF and VHF won't interfere?

Here's a diagram of everything I described above.

http://www.digitalhome.ca/forum/picture.php?albumid=500&pictureid=2482

1. Is stacking worth it? Or will the combined losses of the 2 PCT baluns (plus 2x 5ft RG6) just cancel the potential 2.5db benefit?

The baluns are in parallel, so they aren't combined (i.e. 2 is no worse than 1). The loss from 5 ft RG6 is also negligible. The only significant loss is from the combiner, and that is why you only get 2.5dB instead of the theoretical 3dB. So to answer your question, combining is worth while. Certainly better than trying to combine them if they are pointed in different directions.

3. I might aim the remaining antenna (our current clone) at CKVR to get a watchable picture, then combine the two using the 7777's seperate VHF and UHF inputs. Using a 4bay clone I know is not ideal for VHF, but it works for me anyways. Do the regular antenna seperation rules still apply, or does it not matter seeing as the UHF and VHF won't interfere?

Yes they do. Theoretically you need even more space for a VHF antenna, but most people ignore that.

3. I might aim the remaining antenna (our current clone) at CKVR to get a watchable picture, then combine the two using the 7777's seperate VHF and UHF inputs. Using a 4bay clone I know is not ideal for VHF, but it works for me anyways. Do the regular antenna seperation rules still apply, or does it not matter seeing as the UHF and VHF won't interfere?

You should make a VHF loop or a 2 bay bowtie sized for VHF. They look easy to make and should be alot better than a clone UHF antenna

Sounds good, I might just ditch the clone then, but I hear seeing as the antennas are used for different bands, the spacing is less critical? It was just an idea i was toying with. It's not an actual VHF antenna either, just a UHF 4bay clone similar size to the 4221HD actually.

More critical would be the beam widths. I live in the absolute worst area, as Hamilton and Toronto are 170 degrees apart. Luckily, Buffalo is smack in the middle, so I'll aim the stacked 4221HDs for WNYO. I'm praying the LOS and the 40+ dB I have on the weaker TOR/HAM channels (CITS 35, CIII 65, CKXT 66) and the preamp will compensate. I refuse to use a rotor or try two seperate antennas, too much hassle.

And the splitter? What's the difference between the $2 and the $6 one on SaveAndReplay?

@little-infinity
I have the same setup as you picture without the extra clone antenna. I used the more expensive CM3212 splitter and 3ft equal coax lengths. These go to a CM7778 preamp which I have set as combined UHF/VHF and FM trap turned off. My stack is on a rotator which makes it easy to find the happy spot. For me, I aim 162 degrees which is to the West of Buffalo. Oddly enough this is where the signal for ION peaks. The stack greatly increases the side lobes so receiving Toronto channels is no issue. Sometimes OMNI2, CITY and SUN will have 1 sec. dropouts and I rotate to get clear. When these go full strength rotating should be unnecessary. When you stack, align the reflectors and the whiskers of both antennas and butt the black caps on the reflectors up against each other. Good luck with stack.

As mention combining antennas from different directions will weaken all 3.5db or atleast have the power.This means half strength for WGRZ.A/B switch is a far easier.

...combining antennas from different directions will weaken all 3.5db ...
I don't see that in the Knowledge Base (http://www.digitalhome.ca/forum/showpost.php?p=675713&postcount=16)??

Yeah.

Are you sure?

You lose 3.5dB if you split the signal into 2 outputs right? If you combine the 2 antennas properly I doubt you would lose that much off the bat, as long as you phase them correctly. I didn't notice a drop in WGRZ's signal. It was no better with 2 antennas than it was with one.

First off, there is a difference between ganging and stacking. I am refering to stacking where you will see or should see an IMPROVEMENT in signal strength if all procedures are followed for stacking. Ganging you are more likely to see a drop in signal strength. If you do not see a big improvement with a stack, you will still see an improvement in consistency- which equals less dropouts. I base this mostly on my first hand experience with a stack, and there also a thread somewhere in this fourm that supports this.

I understand.

I ganged because Toronto and Hamilton are waaaay to far apart at my location. Thus I needed one antenna to cover one axis (Toronto-Hamilton), and another to get Buffalo. I've never experienced dropouts on any other station except WGRZ. I will either have to peak for it, or *gulp* cash in another 4221HD for a stack, and THEN ganging with the antenna for Toronto.

Some weak Toronto and Hamilton digitals were just far too weak to take the -30-50dB hit from the side lobes. That was enough to put even strong LOS stations on the weak side. I hope this changes after 2011.

Unless stacking somehow improves the beam width?

I hate my location to be brutally honest. But I bet there are worst places to live for OTA so I shouldn't complain :P

Stacking [2 antennas in the same direction] will give you gain, minus the loss from the splitter/joiner, which will still give you a net overall forward gain. However, you may lose some back door and side lobe effects because stacking will put the focus of the antennas in a more directional mode [more directional mode is where the gain is achieved when stacking]

Stacking: [using muliple antennas stacked and pointed in the same direction]
If stacking 2 antennas together gives you a calculated gain of 6dB, then the addition of a reverse splitter will suppress 3.5 dB which will leave you a net gain of 2.5 dB.

Ganging: [using multiple antennas simultaniously but pointing in different directions]
If ganging antennas together with a reverse splitter in differing directions, then you haven't added gain, you've just added directionality, so the net loss is 3.5dB with no gain to make up for the loss created by the added splitter.

I guess you're right. I recall someone told me the splitter only cost 0.5dB when used in reverse.

Strange though because I did not observe any loss on the stations. In fact Toronto stations saw a huge benefit (over 30-40%). Most of Buffalo stayed the same.

Only 2 Grand Island stations managed to lose. WNED was the big one -30%, WUTV a little less -10%. I attributed this more towards the fact that they are stronger and the toronto antenna (2) is probably picking them up from the side causing some interference/out of phase.

I'm gonna space the antennas more and peak the first one for WGRZ instead of WNYO. I'll see what I get from that. In theory if I do this WGRZ should be more reliable, and Hamilton will benefit. The antennas will less likely interfere.

Though I still do not see where this -3.5dB loss comes into play. I guess I shouldn't worry if it doesn't show up on my tuner....strange.

Spacing the antennas correctly is critical- usually more is better as long as not too low, mine are about 4 feet from each other, the ganged ones, the stack of 4221HDs basically touch each other.

In theory, ganged antennas should equal less signal strength, BUT, each location is different and the way signals bouce around could relate to increased signal strength for some channels.

In my location, the stack of 4221HDs clears the roof line and is aimed at BUF, the single 4228HD is aimed toward TO. When I just use the stack all BUFs come in, but when I add the 4228HD that is aimed to TO, some BUFS INCREASE in signal strength- e.g., channel 14.1 WUTV, goes against all theory of ganging. Somehow the 4228HD is adding some signal to the stack even when aimed to TO, but maybe it is getting some WUTV signal that is bouncing off nearby buildings... Not sure, but in my case, adding an antenna in a gang gives me increased signal strength. For my set-up, and location- it took me a very long time to get the results I wanted- some things were straight forward- did the stack with hacks, but others took a lot of exploration and trying things that went against theory.

I'm not sure what any given loss would be on a reverse splitter. I'm sure there is a wide variety of splitters that contribute to variable amounts of in-line loses. I was just using that 3.5 dB loss as a figure as a point of reference as it was stated earlier as being the loss factor. I'm sure some splitters are far less loss and some may even be more than 3.5dB.

As far a spacing on ganged antennas, 25" is a good minimum starting point. If your antennas are aimed at right angles,... 90° apart or 180° apart then the minimum spacing rule goes right out the window. I had my 4221's at 90° apart and they were only spaced 12" apart on the same mast to acheive the best results.

goforit,
aiming and adding antennas at different angles can be bewildering at times. Sometimes the opposing antenna may acutually pick up a stronger signal from a reflection source and overpower the LOS source giving you an increased signal strength.

example 1: If I aim an antenna south I get 12.1 from Erie PA. at about 50%, yet if I aim the antenna north [facing into my neighbours sat dish] I get 12.1 at 100% rock solid.

example 2: If I aim one antenna to Erie and one antenna to the north, I get anything from 20% to 100% depending on how the battle is won between the LOS and reflected sources of the same signal [multipath is a signal killer];)

Several posts about signal losses from reversed splitters have been moved here from the Mississauga thread.

Readers can enter "splitter loss" into the Search This Thread tool to see previous facts and info about that issue.

Can I flip Antenna 2 so that the balun connector points upwards? The physical antenna looks the same either way so will that affect gain? I'm doing this mainly because my joiner cables are only 3 feet long and there's alot of stress right now if I want to separate them more than 20 inches. I can only do this if I vertically rotate the antenna 180 degrees. The cable looks very twisted at the top and bottom connectors.

Can I flip Antenna 2 so that the balun connector points upwards? The physical antenna looks the same either way so will that affect gain? I'm doing this mainly because my joiner cables are only 3 feet long and there's alot of stress right now if I want to separate them more than 20 inches. I can only do this if I vertically rotate the antenna 180 degrees. The cable looks very twisted at the top and bottom connectors.
no, don;t flip. They will cancell each other out. Think of 2 speakers out of phase.