wireless module availability which can works in NLOS(non line of sight)

Hi Friends,

I am designing a temperature data logger. I just wanted to know is there any wireless module in market which works in NLOS(non line of sight). As in my project, sensors in different rooms need to send data to a central data logger. Is this feasible.

Thanks in advance

It depends....
First, the distance matters, too. A few meters is easier to handle than a few kilometers. You have not specified the distance.
Secondly "non line of sight" is also a very non-specific term. It could mean anything except line-of-sight. To advise you, one has to know what kind of environment it is.

However, in general, it is easier to get descent performance on slightly lower frequencies, than on microwave frequencies. Therefore 433 MHz and 860 MHz non-licensed bands work better "around the corner" than 2.4 GHz or 5 GHz. The problem depends is also how much noise (other users, for example) you have on the selected band.

Start by checking those border conditions, and you have a reasonable chance of finding something, which works more than a few ten meters. Provided, that there is some kind of RF path. Miracles do happen occasionally. However, they happen very seldom to engineers, if they have not been designed in from the beginning. Therefore, if you NLOS is through too tough environment or very RF-absorbing materials, it is really tough. In simpler cases, such as through a light wall, or if there is a usable RF path in general, you might succeed with standard modules.

Thanks for the reply.
Area to be covered is less than 500mtrs.

You can use Zigbee or nRF24L01 which comes with power RF amplifier and antenna not the one without RF power amplifier and with patch antenna.

sensors would be kept at another room at a distance less than 500m from the receiver with walls as interferance

nRF24L01 can be used.

I have no experience about wireless communication!
mark..

Thank you friends, but it seems this module is very costly...any other module other than this?

Greetings,
You need to be more clear about the required range and what cost are you expecting for RF module?
Moreover, range and cheapness does not go with each other. It is easy to find cheap RF modules below 100m (that too for open area), for ranges past 100m there are no cheap modules, you have to use directional antennas and power amplifiers for antenna gain but that too for open area. For indoor purpose 500m is difficult to achieve.
One way is to use RF repeaters at proper distance but for this you need more RF modules. One more thing, you need to take care of transmitting power of your RF module, it should comply with government regulations such as power, range etc.
Here are few links which may help you :-
1. Product said above - http://www.nordicsemi.com/eng/Products/2.4GHz-RF
2. NRF24L01 real life range test - http://hallard.me/nrf24l01-real-life-range-test/
3. 2.4GHz Transceiver IC - nRF24L01+ - http://www.sparkfun.com/products/690
4. 2.4GHz Transceiver w/ Power Amp +PreAmp nRF24L01+ - http://yourduino.com/sunshop2/index.php?l=product_detail&p=190
5. NRF24L01+ 2.4GHz Wireless Transceiver Module - http://dx.com/p/nrf24l01-2-4ghz-wireless-transceiver-module-126467
6. RF24 Library: Driver for nRF24L01(+) 2.4GHz Wireless Transceiver -
7. NRF24L01 Module With PA And Longer Distances - **broken link removed** & **broken link removed**
8. nRF24L01 2.4GHz Radio/Wireless Transceivers How-To : **broken link removed**
9. nRF24L01 with a MAX2240 Power Amplifier - http://forum.sparkfun.com/viewtopic.php?t=6760


Or you can you these cheap RF modules as repeaters :
1. RF Modules Tx & Rx Pair 433 Mhz ASK - **broken link removed**

Or
NEW LONG RANGE UHF TRANSMITTER MODULE-
http://secure.oatleyelectronics.com//product_info.php?cPath=47&products_id=791
&
http://secure.oatleyelectronics.com...d=747&osCsid=f593eae3a0a67f65b37bf731a0488f13

Or Contact this seller :
http://szmellow.en.alibaba.com/prod...iver_433MHz_for_Long_Ranges_Transmission.html
claimed range by manufacturer : Distance: 100m-1800m
Power: 10mw/20mw/50mw/100mw
Interface: TTL/RS232/RS485/USB RF
If it works for long range.. Do tell me!!!

Some more long range modules:
- **broken link removed**
- **broken link removed**
- **broken link removed**
- **broken link removed**
- **broken link removed**
- **broken link removed**
- http://www.sparkfun.com/products/155

- http://www.digi.com/products/wirele...dules/point-multipoint-rfmodules/xtend-module
- http://www.linxtechnologies.com/en/products/modules/lt-rf-transceiver
- http://www.digikey.com/us/en/ph/linxtechnologies/lt.html
- http://www.csgshop.com/product.php?id_product=86
- http://www.seeedstudio.com/depot/2km-long-range-rf-link-kits-w-encoder-and-decoder-p-321.html


Figuring out wireless transmission distance - http://www.moxa.com/newsletter/conn...ssion_distance_from_wireless_device_specs.htm

Whatever module you choose to use, use it at least 2m above the ground.

Good Luck