1
\$\begingroup\$

I've to implement a wireless communication system. Details are as follows.

  • Range is about 600m
  • Point-to-point communication
  • No LoS is available. (but not highly obstructed)
  • Won't need much higher data rates.
  • Should be reliable.
  • No constraints with supply power, size etc...
  • Intended to handle with PICs of Arduinos.
  • Price is not a major issue (but prefer a reasonable price..)

Please point me to a proper transceiver module that can be used for the purpose. Don't have prior experience with wireless modules (so, you can assume fine details and then let me know of them), a straight answer is much appreciated..

Thanks!

\$\endgroup\$
1
  • \$\begingroup\$ Please don't ask another question that is exactly the same. Instead, you should improve your existing question with more information as needed. \$\endgroup\$
    – W5VO
    Commented Aug 17, 2012 at 12:19

3 Answers 3

Reset to default
2
\$\begingroup\$

You ask about the Xbee-Pro 900.

enter image description here

As the name suggests this works in the 900 MHz. The datasheet mentions a LoS range of 3 km, but since you don't have LoS that may be considerably less. The module has an RF connector, though, so you can connect an external high-gain antenna, which, again according to the datasheet, would increase the range to 10 km LoS. Should be enough for your application.

Your link is to an eBay reference. I wouldn't buy from sources like that. For Sri Lanka Digi has a distributor in India, which will probably give you better support. (Many product you buy on eBay you can't get any support for at all.)

Further reading
Xbee-Pro 900 Manual

\$\endgroup\$
6
  • \$\begingroup\$ << 50 mW (17 dBm)??? HAHAHHA....That's a freakin' toy radio. You be lucky to get it to talk back to an AP more than a few hundred feet with a clear line of sight >> This is someones comment about this module. Really, how can we expect such a range (up to 10km !!) from this little o/p power?? \$\endgroup\$
    – Anubis
    Commented Aug 18, 2012 at 12:35
  • 1
    \$\begingroup\$ @Anubis - Who posted that where? Without further explaining this looks more like trolling. \$\endgroup\$
    – stevenvh
    Commented Aug 18, 2012 at 12:45
  • 1
    \$\begingroup\$ @Anubis - The FGR-115 mentioned in another answer claims a 100 km range at 1 W output (granted, that's LoS). Due to the inverse-square law this would be 10 km LoS with just 10 mW, or 3 km at just. I think that person should show evidence for his claims. \$\endgroup\$
    – stevenvh
    Commented Aug 18, 2012 at 13:01
  • \$\begingroup\$ I found it on some other forum (I'm searching everywhere..). Well, I thought that makes sense, but now I feel I (too) got fooled. 10km is via a high gain antenna. 3km from 50mW right? (Hope be that is achievable...???) \$\endgroup\$
    – Anubis
    Commented Aug 18, 2012 at 13:13
  • 1
    \$\begingroup\$ @Anubis - That's what I would expect. The big unknown is the loss you get because you don't have LoS. I don't know if there is data on loss due to a forest of banana trees :-/. 600 m is 10 km / 16, so your required power should be 1/250 of that for 10 km. That's 24 dB you could afford to lose. \$\endgroup\$
    – stevenvh
    Commented Aug 18, 2012 at 13:22
2
\$\begingroup\$

While Xbee might be the easier option, but an alternative, with a much lower cost, but requiring some more "work" on application layer to define the communication protocol could be the RFM12B, which sells for about $12 a pair. It has a longer range version called RFM12BP, but I am not certain about it's cost. Jeelab's JeeNode, which can be programmed using Arduino environment (as an option), embeds RFM12B for ISM band short-range communication. The data-rates are not high, and infact lower than Xbees (or other Zigbee implementations).

Do note that ISM band has restrictions around max. transmit power, and max. continuous transmit duration in many countries, and same set of ISM bands are not really globally accepted. For instance, while many people advertise 434MHz as a universal ISM band, there are exceptions.

\$\endgroup\$
1
\$\begingroup\$

You didn't mention price range, but if it is not an issue, consider Freewave. They have long range radios (km), and have a simple rs232 (with TTL level option) interface. Take a look at the FGR-115.

For a lower price alternative, the xbee mentioned in another answer, or Digi's XStream.

\$\endgroup\$
5
  • 1
    \$\begingroup\$ Thanks for quick reply. Price is not a major issue, (edited the post). I'll check what you suggested. Any idea on XBee? And what about licence issues, does this use ISM band? Please give more details if possible. Can you link me to any specific module? Thanks ! \$\endgroup\$
    – Anubis
    Commented Aug 17, 2012 at 7:16
  • 1
    \$\begingroup\$ If you refer to a specific product a link is appreciated, preferably to a datasheet. \$\endgroup\$
    – stevenvh
    Commented Aug 17, 2012 at 8:12
  • 1
    \$\begingroup\$ @Anubis - I'm not sure this is the right product for you: is 1200 dollar a reasonable price? \$\endgroup\$
    – stevenvh
    Commented Aug 17, 2012 at 8:18
  • \$\begingroup\$ @stevenvh Whoa... I don't honestly believe 1200$ is reasonable. Aren't there any module something below $250 ? What's your idea about [this Xbee module](ebay.com/itm/XBee-Pro-900-Module-RPSMA-/…). It's 78$. It also gives 3 year warranty for additional 15$ s.. \$\endgroup\$
    – Anubis
    Commented Aug 17, 2012 at 9:37
  • \$\begingroup\$ We used this for a UAV a few years ago, where reliability (and encryption) was paramount. After the question update I realized that this is not what the OP is looking for. One of the Digi (previously Maxstream) products would probably be fine (Xbee or XStream). \$\endgroup\$
    – apalopohapa
    Commented Aug 17, 2012 at 22:44

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.