900 Mhz Vs 2 4ghz Wifi4games
| 900 MHz wireless and WiFi (2.4GHz) are different technologies but sometimes used interchangeably |
The 802.11 standard provides several distinct radio frequencies ranges for use in Wi-FI communications: 900 MHz 2.4 GHz, 3.6 GHz, 4.9 GHz, 5 GHz, 5.9 GHz and 60 GHz bands. Each range is divided into a multitude of channels.
900 MHz wireless and Wi-Fi (2.4 GHz) are sometimes used interchangeably in the access control world to describe solutions that do not require running wires all the way to the opening. It’s true that, as wireless options, both technologies offer some general advantages over traditional hardwired solutions.In this article, Minu Youngkin, Allegion, Integrator Marketing Manager shares her thoughts and knowledge regarding both wireless and Wi-Fi technologies.
First of all, wireless overcomes architectural limitations. As any integrator knows, historical buildings, glass doors and atriums typically have openings that are difficult - and costly - to hardwire.
Wireless also eases budgets. Some openings, such as those with drywall or wood frames, are easy to wire. However, if there are numerous openings, labor costs can rise quickly.
- DECT 6.0 vs 900 MHz vs 2.4GHz vs 5.8 GHz DECT 6.0 (1.9 GHz) 900 MHz 2.4 GHz 5.8 GHz FCC approved frequency for cordless telecommunication Baby monitors, microwave oven Wi-Fi electronics (routers), wireless stereophones, wireless gaming pad Some Static Electronic devices. Interference, bad sound quality Interference, bad sound quality.
- Which is better in a cordless phone 2.4 GHz, 5.8GHz or 900 MHz? Report Abuse. Are you sure you want to delete this answer? For example, I have 3 cordless phones in my house. My office has a 5.8 Ghz phone, while my living room has 900 Mhz phone and my kitchen has a 2.4 Ghz phone. Once, I had two 900 Mhz.
- I have been told that a 2.4 GHz phone will get a lot more range than a 900 MHz phone. I have also been told that a 2.4 GHz phone is far less likely to experience interference from household appliances than the 900 MHz. I have also been told that the 2.4 GHz vs 900 MHz technology does not affect the range of the phone at all.
“It generally takes five to six hours to run wire to an opening, compared to less than an hour with a wireless option,” says Brad Aikin, product leader, electronic commercial locks at Allegion. “If a client wants to reduce costs, wireless is a solid way to do it. Likewise, wireless allows integrators to expand the number of openings because the cost per door is less.”
Wireless is flexible. “With wireless, you can avoid coring doors or cutting around the door,” Aikin says. “Plus, relocating a lockset from one door to another is easier because it’s all in a self-contained solution.”
However, while they share some commonalities as wireless options, 900 MHz and 2.4GHz Wi-Fi are not identical solutions. So which is better? Actually, selecting one over the other is really a choice driven by the type of application and the goals of the client.
“There are advantages to both 900 MHz wireless and 2.4GHz Wi-Fi, as well as trade-offs,” Aikin says. “Determining which one is the best fit really depends on where and how it will be used.”
When 900 MHz is the best option
900 MHz is the ideal solution when real-time is essential.
| Wireless overcomes architectural limitations such as historical buildings, glass doors and atriums |
“900 MHz is definitely the way to go if your client wants the ability to communicate to the device in 10 seconds or less, such as applications providing remote lockdown or real-time management of changes to employee credential access,” Aikin says. “The Schlage AD-400, for example, has a patent-pending Wake-Up On Radio™ feature that allows real-time communication from the host to the device, and monitors all alarms and events in real time—all while preserving battery life.”
Integrators also use 90 MHz when signal range may be problematic. A 900 MHz wireless connection typically has a larger range than a 2.4GHz Wi-Fi connection. While all RF radio waves can be subject to some interference, Aikin says, technology and architecture configurations exist to ensure reliability and performance. In addition, 900 MHz operates on a lower frequency range that allows it to penetrate through buildings easier and be more resistant to interference.
“It’s always important to look at existing frequencies in the environment to determine if they are compatible with the frequency you’re proposing, or if additional measures are required to minimize interference,” he says.
When 2.4GHz Wi-Fi may be considered an option
Current solutions for 2.4GHz Wi-Fi—which is not online at all times—also offer some benefits. 2.4GHz Wi-Fi is a worthwhile consideration for your client when real-time access control is not required: A client who wants access control but doesn’t need real-time access is a candidate for 2.4GHz Wi-Fi.
“Current Wi-Fi locks communicate on a time delay, typically 12 to 24 hours,” Aikin says. “In these cases, the client can afford to have the device operate independently offline and wait for updates that are pushed down only once or twice a day.”
WiFi is often used in applications where access rights seldom change. If the client has low turnover or very infrequent changes in access privileges, then updating credential information with a time delay only once or twice a day may be adequate.
WiFi is also an option when the use of the existing IP infrastructure is preferred. If your client wants to use the same network architecture for locks as they do for managing other communication to printers, work stations and other devices, then 2.4 GHz Wi-Fi may be considered.
The final decision
The decision to use 900 MHz wireless or 2.4 GHz Wi-Fi is straightforward for some projects. Often, though, several factors need to be assessed so clients can prioritize goals and determine the trade-offs they are willing—or not willing—to accept.
I have recently been contracted by a client of mine to facilitate the wireless communication of his 'home' offices and a secondary site.
The primary site is the top two floors of a 5-story office building (15m height more or less) an the secondary is one of two open 'lots' (which one is TBD by management). The ground distance from the secondary sites is a little more than 2km for the one closer and around 2.9km for the one furthest.
The link will be used to transmit the video feed of 1 (or even possibly two) IP cameras and some kind of Ethernet-enabled environmental or weather sensor. I have checked the necessary b/w for the cameras and both 900Mhz and 5.8Ghz are more than adequate for even 4 of them, much more for 2. I have also verified that there is clear line-of-sight to both possible installation points and that the 60% Fresnel Zone clearance is more than covered. Bear in mind that this is my first long distance link (long with or without quotes) and I hate to admit that wireless physics is far from my strong suit.
The ultimate point of my question is that although I have read a lot about frequency choice the last few days, I continue to find some ambiguity (I know it is just me that finds it ambiguous). Most sources, like this one, agree that although the lower frequencies have less losses over a given distance (free-space-loss I learned it is called) they need larger antennae for the same 'strength' of trasmission (is 'gain' really the same as 'strength'?).
So, for the given distance of 2-3km and given also that all typical requirements are met, which is preferable (or do I dare say 'better') frequency? Should I choose 900Mhz with a relatively 'small' antenna on the basis that 3km is not really 'long distance' and that it will provide a link with less attenuation ergo less retransmits ergo higher overall speed? Or should I choose the 5.8Ghz option for the superior b/w (I am still not very sure about this, please correct me if wrong) on the basis that at this distance there is no real difference so why not take the 'better' one?
On a side note, should I stay to the beaten path of true WiFi or should I consider proprietary bridging solutions like the ones from Ubiquiti? I have a lot of experience with their Access Points and am really satisfied, so I would not mind integrating one more of their products in my client. In any case, I am looking for an optimal solution, choice of vendor is of very little concern at this point.
Forgive my ignorance and the possible mistaken use of language.
UPDATE:I arranged to have a spectrum analyzer on loan for a couple of days. I will make sure that the 900Mhz band is reasonably clear and proceed down that way.
UPDATE 2:I had the aforementioned equipment available to play with for a day and a half. The conclusive finding is that the 9Mhz band is almost 'empty' in the area, as one suggested here, so that takes care for the frequency choice issue.
Concerning the equipment now, I am going with Ubiquiti AirMax Yagi antennae and matching RM900 2x2 radios. Preliminary testing on my part and from the client's employees shows that performance exceeds expectations.
On a side note, the chosen 'lot' is the one that is 3km away.
2 Answers
3km is approaching the limit of 5.8GHz equipment with reasonable size antennas and typical WiFi radios. With some of the best equipment you can only get ten times that distance with some caveats.
900MHz can easily go 3km, and much much farther. 900MHz is used for a wide variety of devices for this reason, so there's a good level of background noise. This might be a problem, especially if your neighbor has a 900MHz phone or similar (not a popular frequency for phones these days, but people hold on to technology for a long time too). I would avoid this frequency unless you're in the middle of nowhere (which you aren't). The 2.4GHz spectrum has worse problems with this, our microwave at work blasts 2.4GHz (I'm sure it violates FCC something or other, but nobody really cares as we have 5GHz WiFi).
Chris SChris SChris S's answer is incorrect in several areas.
3km is not approaching the limit of 5.8GHz. Similarly, that's not as big of a distance as for 2.4GHz wifi either. Chris says 10X, I say 100X the distance is possible. The longest range 5.8GHz wifi that I've heard of is 304KM with a 1.2M hand made antenna (See: Long Range Wifi). I believe it went over water so there were not any thing in the way of the signal. It used Ubiquiti radios. I don't know if it was reliable, but to get a connection and send data over that distance is nothing short of amazing.
I used to work for a wisp carrier and had wifi radios about twice the size of your hand easily going 10KM with good line of site. I personally had wifi on my house going 8KM without any issues. Amazingly, they were only 500mW.
We were using 5GHz radios and a mixture of Ubiquiti and Microtik hardware. They work almost flawlessly.
While it is true that with lower frequencies you need bigger antennas. You'll notice that your home wifi doesn't have large antennas. Neither do 5GHz ones.
In reality, 2.4GHz should perform better, but 5GHz in my experience works just as well.In theory, 5GHz could be affected by rain fade, but I didn't find that even over the 8KM link.
As for 2.4GHz and other devices like microwaves and cordless phones inside the office, it doesn't even factor in. The reason it doesn't factor in is that you'll be using directional antennas. Better still, if the antenna is on an iron roof you will be shielded from all that noise coming from inside the office/house.
Having said all of that, I will say that it's not perfect for every situation.You need:
- Line of site between the two buildings. Factoring in the freznel zone (good open clearance)
- A suitable place to mount the antenna to achieve point 1.
- Hopefully not much wifi traffic facing your directional antennas (no gaurantees there, but it should be workable) even in a reasonably crowded wifi space.
Freznel zone looks like this:
By the way, I've had trees in the way of the freznel zone and in some cases right in the middle and it still worked, although it does affect the performance a lot. Install your antennas as high as practical/possible.
You can still get interference issues. Usually because of other devices transmitting in your direction at the same frequency. So it's not perfect. Directional antennas help a lot with that.
I can recommend the 5.8GHz radios simply because I know they work well. And yes, provide good bandwidth! From memory I used a Ubiquity Bullet M5 with a patch antenna (another brand). The other end was a less directional antenna feeding multiple clients but used a similar Microtik radio.
I don't know of anyone who uses 900MHz. But I do see you can buy them at around 3X the cost than 2.4 or 5.8. Stick away from it, it seems uncommon. In several countries the 900MHz spectrum is quite crowded anyway.
Update: You've been looking at the airmax antennas and the 900MHz radios. While I think performance should be great. I think you may be spending much more than you need to.. perhaps a little overkill!? 3KM is not a long distance. I'd try some of these if you can.
http://www.gowifi.co.nz/antennas/5-ghz/directional/5.8-ghz-27-dbi-cast-reflector-grid-antenna.html combined with a Bullet M5.
Update2: You can also mitigate interference issues using polarized antennas. Here's a good write up that explains the concept. From memory, we used horizontal polarization. As I recall sometimes if I set the client radio to vertical polarization I could see maybe 12 AP's. But when setting it to horizontal I only saw 3 or 4 and half of them were ours.
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Matt