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1240AG, looking for antenna B and G with range 500+ FT

Hi there. we are looking for antenna that would give us a distance of 500 FT. this is for a warehouse. that would be mounted on the ceiling, as well it would need to be 2.4ghz as the computer will be running B and G standard.

i'm assuming we would be looking for a omni direction antenna. any help would be great.


Re: 1240AG, looking for antenna B and G with range 500+ FT

First, keep in mind that without a site survey, no recommendation is truely valid; there are so many things that could affect your transmssions, even in a fairly open warehouse.

Generally speaking, given good line of sight, and clients with good reception and selectivity, a pair of 5.5dbi omnis, set up for diversity, would likely work (for at least most of the area).

More likely, you'll need at least two APs, each with some high-gain omnis ... maybe three. What is the storage rack layout? How high are they? Do you have line-of-sight from one point on the ceiling to *every* possible reception area?

Are the clients man-carried or machine mounted? Do you suppose that a fork-lift truck with a scanner on the forks can block a 2.4G signal (yes, it can, very easliy)?

You need a good, comprehensive site survey.

Once you determine what you need for coverage, then compare that to the budget.

If the budget falls short, either get more money or start dropping lower-priority needs until the implementation fits the budget.

Good Luck



Re: 1240AG, looking for antenna B and G with range 500+ FT

All excellent points made by Scott.

However, since this is a warehouse, yet another important factor will be variations in the stock levels as well as the types of materials that will be stored in the warehouse. For example, pallets of containers containing liquid are one example of types of warehouse materials that can have a significant effect on RF propogation. Depending upon the type of materials, another factor is how variations in the amount of product in the warehouse can also significantly affect the RF environment.

One field experience that was shared with me from the by a Cisco engineer demonstrates this:

An RF site survey was performed in a large manufacturing environment and installation took place according to the survey. Initially, everything was just fine. However, the design engineer was called back out later because the customer was complaining about coverage issues in certain areas.

It turns out that the coverage issues were the result of large tanks (empty during the initial survey) that were subsequently filled with liquid - causing the RF signal to be absorbed.

The point is that a warehouse can also be a dynamic environment from the standpoint of RF propogation.

While there is no magic bullet design to cover every scenario, you will probably want to consider a worst-case scenario (accounting for the highest amount of product in the warehouse) and then factor in any same channel interference for times when stock levels may be at their lowest.

One approach might be to consider the use a yagi antenna to shoot down each aisle. You would alternate which end you mount the ap/antenna as you go from aisle to aisle. For example, aisle 1 would have an AP at the North end of the aisle, Aisle 2 would have an AP at the South end of the Aisle, Aisle 3 North, etc.

At each aisle you would alter the channel used (CH1, CH6, CH11, CH1, etc.) That way you could have line of site/near line of site on each aisle. However, you need to evaluate if this is a viable approach for your application. For example, this may or may not give sufficient overlap if you intend to implement Voice over WiFi at some point. Performing an RF survey will help you determine what your coverage will be.

You may also want to look into Cisco's lightweight ("Unified") wireless products (WLC/WCS) which offer AUTO RF features to dynamically adjustm RF power levels as conditions change.

Hope this helps,

John R.


Re: 1240AG, looking for antenna B and G with range 500+ FT

More specific to the original question, there are a number of antennae that are rated for longer distances. You may want to review the suitability of the following:

Cisco AIR-ANT1728 is a 5.2dB omni antenna. You would use two of these for diversity operation. It gives a rough estimate of range as 497 ft.

However, that rating can only be used for rough planning and is, likely, based upon measurements in a relatively open space.

(Your mileage may vary).

Also, keep in mind that to get to that range, the AP was running at a data connection rate of 1 Mbps. Might be OK for barcode scanning, may not be suitable for other applications.

- John R.

Community Member

Re: 1240AG, looking for antenna B and G with range 500+ FT

In a warehouse, if it is a large warehouse, I would not do use omni's.. most definitely not, treat it as if it were an outside area with multiple obstacles (for example: a field with tree.) Dynamic obstacles at that.

Try to place AP's so that you get overlapping coverage coming from three different directions, that way if pallets from one area get in the way or absorb RF you still have signal coming from another direction.

I would use directional antenna's to minimize the RF interference. Expect alot of interference if you are mounting up in the ceiling. Usually this isn't an issue in a warehouse due to the low speed required for most applications.

A nice alternative i've used hyperlink tech (search on them, you'll find 'em) or someone similar to provide sectorized antenna's that you can wall mount at the ceiling and allow you to get very directed coverage patterns.

I've used sector antenna's with 14/19db gain and they perform awesome in warehouse environments.

Hall of Fame Super Red

Re: 1240AG, looking for antenna B and G with range 500+ FT

Scott,John and Raoul,

I thought that these were some really excellent answers that offer some good insight. All deserving of 5 points!!

Great work here!


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