Wireless Service Providers → Omni coverage

Have been looking into the antenna side of things and ran into some small confusion. If I mount an Omni for starters instead of a sectored omni the chart at e-com says that the omni will not hit the ground untill about 1600 feet at 200' high and at 14 degree vertical per Pacific's stats. The question is, will I have any signal at all directly below the antenna or even up to the 1600 foot mark? Will the signal be there just real weak? I plan on using smartbridge xo2 with output to omni, with airbridge total for cpe's. The town I plan to cover is primarily under or with in the 1600' mark but of course the rural area is wide open 360degrees for miles and miles, I have the opportunity to cover this whole area with at least a six mile radius with no other WISP's. I would like to use the omni to check signals and get some customers in the rural to start then upgrade to a three sector omni with with one AP split or add the three sector and two more AP's at the same time. Any comments would be appreciated.
Thanks

It all depends on which omni you get. If you get a 9db omni then you will have a usable link very close to the tower but it probably will not be strong enough to get miles and miles. Now if you use a 15db omni you will not be strong enough close in and actually at 200' up it would not be a good choice at all. This is whats good about a manual downtilt sector. You can get a high db and aim it where you need it. I started with a omni but I wouldnt do it again. If it was not in my budget to get 3 sectors I would buy 1-90degree sector and start with that. Also, I would go with a horizontal sector. Thats just me though.

The answer is no signal to very very weak signal.

Check the antenna's vertical beamwidth.
If its 14* as you mentioned, chances are, the inner circle of clients WONT GET SIGNAL.

Buttom line, you overshoot. Use a lower gain OMNI antenna which usually translate to higher vertical beamwidth.

Or use a sector antenna. Thats just about it.

If you are low on budget, then I suggest buying from some Eastern European manufacturers (interline.pl and dipol.com.pl). They sell cheap sector antennas. Get the slotted waveguide antenna each less than $150

Well,
The 14* was the 9dbi antenna. The 12dbi was at 7*. Pretty much it seems at that hight I will have to sacrifice either way I go, be it a sector or omni. With sector I will have to point it so far down that I will loose distance and with an omni I could have up close but no distance. I have to start with a full 360* pattern or I will never make it off the ground with this ISP. We already have DSL and cable in town so there would be very few subscribe in town and hopefully the majority in the rural area will switch from dial up to us. If I went with sector and pointed it down, how can I tell what angle of tilt to use and still have enough signal to reach my 5-6 mile range? with the proposed 13dbi CPE. There isn't going to be any semi-easy way to tell with out mounting it is there?

How wide open space is wide open. Keep in mind fresnal requirements, but what if you mount the antennas at 150' or 125' or ...?

said by gunther_01:

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The question is, will I have any signal at all directly below the antenna or even up to the 1600 foot mark? Will the signal be there just real weak?

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Every antenna is different, but most of them have side lobes that may or may not project signal under the tower. I have a 13.5 dBi H polarity omni and I can stand under it at close to 100ft in height and get signal. No it is not a cheap unit either as it cost me almost $500 !!!!. While the beam width for Your antenna is rated at 14 Degrees, that just means that the signal is the strongest in that area, it simply fades out at varying rates from there.

Nwn,

Wide open is pretty wide in the flat lands of Illinois. Also at 200' out here I can see the top of the structure at over 9 Miles at a given spot. I realize that I can't see it at 1 mile in some places but for the most part the view is good out here as far as the out of town stuff. In town is a little different and hit and miss. I have looked into some sector antennas and was also wondering about the front to back ratio. One I found has >32db the other is >23db. How much will this affect total output? price of antenna seems relative to this statistic. As far as another structure, I think I may be able to get on the top of the water tower in town but it has other equipment on it namely the towns police and school bus radios. I don't think they will let me but haven't asked yet. it's about 150'.

I have almost a follow up question regarding the difference between a H-polarized omni and a V-polarized omni.

Superdog1 - What is the advantage of going H-polarized on your omni? Is the H better than the V (as eluded to by Superdog1) for closer clients to connect to? Or are you just getting away from interference from another V-pol AP?

Our scenario is we have our main AP on the hill and just put a tower up behind our office as a secondary. But mainly to hit the downtown are (maybe 3 blocks deep by 10 blocks long.) One of the clients that wants service is the tax guy across the street from us (More than 75') away. He would be the closest customer I could sign up.

Yes, it does depend on the antenna for sure. I have a 14db sector with a slight manual downtilt on a 300' tower. Its a hyperlink 180 degree. I can fire up a indoor airpoint in my truck in the parking lot underneath it and get a good signal. Dont try that with a clean antenna like a Maxrad sector though.

I have my 10db omni mounted as follows.

3 5ft standard outdoor antenna poles. The omni is mounted at the top of this which gets it about 3-5 ft above the peak of the roof. I then have 25ft of lmr400 running in through the wall to my access point.

I am getting a really good signal with a client using a yagi and cb3 radio about 1/4 mile away, the Texas Cellnet yagi model. I have another customer right next door using a flat panel 14db roo antenna and the signal is lower with it that with the yagi client. This is probably due to the effect they are mentioning in the other messages above, I jumped into this to get up and running, and while it works well, I am learning as I go.

If I had it to do over again I would get a taller mast, and sector antennas, but I am starting small and learning as I go, and I will have no more than 20-25 clients.

I am in a small "75 homes" neighborhood and am smack in the middle of it on a bit higher land than my customers, I noticed pac wireless has a 9db omni with electrical downtilt, would something like this be better for my application?

Let me know and learn from your expertise.

Joe

Polks,

Please define the:
"with a clean antenna like a Maxrad"
Would this have to do with the front to back ratio. I am interested in the WISP maxrad or the all terrain sector onmi set up they have. Any thoughts anybody on these antennas? What's the big difference between the WISP and the extreme series?

Yes, I find the front to back ratio much better with Maxrad versus other antennas I have tried. As far as the sectorized omni they sell I think its a waste of money. I paid 1k for one when starting out. I did not know any better. You would do better with 3 seperate sectors and stagger them somewhat on the tower. This way you get a little seperation. Not sure of the difference in the two lines they sell.

The electrical downtilt WILL help alot for you.

Use this link to check out your radius of coverage:

»www.ydi.com/calculation/ ··· over.php

The only difference I can find statistically is the front to back ratio is >32 on the high dollar extreme Maxrad compared to >23 on the WISP series sector 120* antennas. Hence the question what is this number? And will it make or break my antenna array? The all terrain sectorized onmi they sell looks to be made of the Extreme series ant.

Jsteng, thank you for the link. It shows that I can get as close as 686' for inner radius and still have horizon for my longest radius. Would that be how you normally adjust the downtilt, too the horizon for the farther radius? It goes from horizon at 8*down to like 2. something miles. All I can say is 686' is better then 1600' with an omni that I had originally though of. At least I cover some of the town now.

I'm getting closer everyday, I Think?

I did some testing with the 120 degree MAXRAD WISP sector. It does have some serious rear lobe signal strength I was suprised about. I was behind the thing over a 1/10 of a mile away and the signal was still very good. Otherwise the maxrad was decent. My testing height is not very high maybe 10 feet over residentiol roof lines and I did have a slight tilt

said by kukur:

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Superdog1 - What is the advantage of going H-polarized on your omni? Is the H better than the V (as eluded to by Superdog1) for closer clients to connect to? Or are you just getting away from interference from another V-pol AP?

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Alof my competitors at the time were using V polarity, so I went to H pol. to get away from interference. H pol. also has a little less multi-pathing issues in an urban environment.

I am also moving to horizontal slowly but surely. It really makes a difference when dealing with home AP's as well. With a 19db flat panel on my house roof I can see close to 10 home AP's. Some of them having as much as 80% signal.

Gunter,

If you really want to capture the immediate surrouning, i suggest you go this approach:

1. get a vertical polarity omni and stick it low/under the tank. this will be your receiver for the immediate area.

2. get three 120* vertical polarity antennas (slotted waveguide is my choice and are usually 180*) and stick this at the highest possible place OR you can stick this at the catwalk and let the water tank solve your front-back interference.

As for downtilt, it depends on how long the reach you really want it to throw. For starter, if you want only 10 miles, then set the downtilt angle such that the outer radius is at 10 miles.

"Horizon" is as far as the eyes can see never touching the groun. Surely, you cant serve the next state. So I sugget that you go only as far as your radio and client can go. remember, 10 mile radius is very far and you will need very serious antenna and radio on your client to acheive this feat. very far but very do-able now with current generation good quality radios.

Another approach is to use splitters to form antenna array:

1. You can couple two antennas such that one is pointing for the distance and the other is pointing to the near field. Make sure they are mounted vertically (not side by side). You can have a high gain antenna on top for the distance and a low gain at the bottom to cover the near field. I suggest different vertical polarity for the near field and horizontal polarity for the top antenna to isolate the two.

2. Some Panel antennas have 60* horizontal beamwidth with about 30~40* vertical beamwidth. You can couple two of these side-by-side to form a 120* sector with 30* vertical beamwidth.

3. Some panels have same vertical/horizontal beamwidth (60H/60E), you can have one vertically and the other horizontally mounted. This way, there is a natural isolation of 20~25dB.

4. Some even go the length of using very narrow beamwidth high gain panels and form an array to cover long range. Here is an example of a system that uses a mixture of filters and multiple directional antennas.
»www.rflinx.com/Amplifier ··· ries.htm

Spacing them is the key. With correct spacing, you can even get higher gain. Wrong spacing, and you get signal cancellation.