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Help finding a transciever — Parallax Forums

Help finding a transciever

MicrocontrolledMicrocontrolled Posts: 2,461
edited 2009-08-03 01:13 in Propeller 1
I am building a project that requires data transmission of up to 5 miles. I am thinking of an Xbee even though I have never before used one. Does anyone know the range of one?

Any thoughts?

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Comments

  • Bobb FwedBobb Fwed Posts: 1,119
    edited 2009-07-30 20:45
    Take a look at www.digi.com/products/wireless/zigbee-mesh/xbee-digimesh-900.jsp "6 miles".
    I don't know of anything that can go further than that, but I haven't really looked for anything.

    Edit: found xbee hardware (link above)

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    Post Edited (Bobb Fwed) : 7/30/2009 8:53:05 PM GMT
  • sylvie369sylvie369 Posts: 1,622
    edited 2009-07-30 21:12
    Digi's XTend and XStream modules are supposed to have a LOT more range than that, but they're also considerably more pricey ($179 from Mouser).

    Post Edited (sylvie369) : 7/31/2009 10:51:09 AM GMT
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-07-30 22:20
    I am going for ACAP (as cheap as possible) smile.gif

    I am on limited budget and the total product cannot have more then $80 of stuff on it.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontroled.


    If it's not Parallax then don't even bother. :-)
    ·

    Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
    Cheap·shipping unless specified!··········150 left!!··


  • 4Alex4Alex Posts: 119
    edited 2009-07-30 22:37
    @Bobb:

    XBees are great but I seriously doubt you can *really* achieve 6 miles with them so easily. There's a good report on actual hand-on ranges on the SparkFun website. Also, antennae and operating environments are very critical in achieving anything like stated 'up to' ranges, especially 6 miles! I've used XStream, they work well, but I never got much more than a couple kilometers with a stubby antenna.

    Cheers,

    Alex
  • DavidMDavidM Posts: 630
    edited 2009-07-30 22:59
    Hi microcontrolled,


    I use the AEROCOMM AC4490-1000M 900MHZ Transceivers, To get that range it's all in the antennas. you will need to get them up high and use as large a "GAIN" as possible. and yhey may need to be directional "YAGI" antennas I think?

    http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=AC4490-1000M-ND

    The AC4490's are easy to use, ( once you figure them out of course), they run at 3.3v.

    your "5 miles" will need to be LINE OF SIGHT, not easy to achieve in a city or built up area!

    regards

    Dave M
  • Ole Man EarlOle Man Earl Posts: 262
    edited 2009-07-30 23:18
    I use XBee's and get 10 miles easy. BUT one end has a Yagi and the other end has a rubber duckie AND it is in a UAV that has clear line of sight from flying.
    Earl
  • BigFootBigFoot Posts: 259
    edited 2009-07-31 01:04
    We are using just the XStream 900 MHz module in one of our PoS products. It has a 5 volt interface and is a little over $100.
    We get over 1000 foot range in downtown Santa Monica and they advertise 17 miles range with the proper antenna. As
    someone else mentioned "its all in the antenna"

    Russ
  • 4Alex4Alex Posts: 119
    edited 2009-07-31 02:57
    @russ:

    Great Antennae AND excellent reflective planes AND slow data rate AND ideal environment AND lots of votive lamps, but I like the XStream transceivers. Simple, reliable, to the point. Somewhat big, though. We used them in mobiles (moving vehicles on highways at highway speed) and this is where you can really assess the 'up to range' specs of a datasheet! we are actually proud of having achieved a few kilometers. Antennae were covert (definitely not visible yagis or whips) and relatively high data rate. 5v not an issue as we used PICs and automotive battery source.

    @Ole Man Earl:

    About XBees: XBees are fine products for embedded comms. But '10 miles easy using a yagi and duckie on uav': really? some yagi and some line of sight! What kind of link is it? You definitely hit some sort of RF jackpot. Your environment must be pure RF bliss... What's the specs of the yagi and how high is it located above ground, the environment (is it urbanized?), the data rate, the overall design, the travel speed of your uav? We'd love to get half of that distance 'easy' with the XBees even if they're NOT moving. We have about 40 in stock, not fessing up to the 'up to' specs. Sorry if I sound a little skeptical but your experience with XBees is much more enthusiastic than ours. Why not share the goods...

    Cheers,

    Alex
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-07-31 15:39
    This will be mounted on a bike (not a motercycle, a bicycle!) and will use the RF link to share information (speed, location, etc.) with other bikes. This would make the enviroment changeable. The module would have to be inexpensive and small.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontroled.


    If it's not Parallax then don't even bother. :-)
    ·

    Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
    Cheap·shipping unless specified!··········150 left!!··


  • Jimmy W.Jimmy W. Posts: 112
    edited 2009-07-31 15:47
    microcontrolled said...
    share information (speed, location, etc.) with other bikes.

    A Mesh network! As long as one bikes is in range you can set them to retransmit until it either hits maximum hop limit or the target.
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-07-31 15:50
    What is a Mesh Network? Do you mean that the closest one recieves the data and then transmitts it to the next closest one untill all or them have received the data?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontroled.


    If it's not Parallax then don't even bother. :-)
    ·

    Mini-Din/PS2 connectors are for sale! 5 for $1! PM me if you wish to make an order.
    Cheap·shipping unless specified!··········150 left!!··


  • DogPDogP Posts: 168
    edited 2009-07-31 17:28
    I dunno if you could modify your project to use these: http://www.bestbuy.com/site/olspage.jsp?skuId=9206548&st=cobra&lp=3&type=product&cp=1&id=1218058780423 , but they've got good range as a two way radio (they should... they're 5 watts!). Good price too ($30/radio), and pretty easy to remove the antenna to add an external one if you need it.

    Of course if you're interested in that, you should definitely read the legal info on it... I have no idea whether you're allowed to transmit data on those channels, or if it's for voice only, and IIRC FRS radios are required to have permanent antennas, so if you modify the antenna, stay off the FRS channels (plus I believe FRS is limited to 0.5W, unlike GMRS, so the range won't be very good).

    DogP
  • Ole Man EarlOle Man Earl Posts: 262
    edited 2009-07-31 19:59
    @4alex
    Do you really know about RF ??
    I send data signals >15 miles everyday on 2.4 ghz with 9dbi omni ants at both ends. Yes it is clear line of sight rural area flat ground. I used to use 20mw at over 5 miles with 15 dbi grid ants. I DO know what I am talking about on this subject as I have OVER 40 years experience.
    XBee or 802.11 on 2.4 ghz doesn't matter. RF is RF is RF. Do some math with Radmobile and see for yourself. I have this knowledge from owning a wireless ISP for over 8 years.
    So don't chid me about RF. On a bet I can show you two 60mw XBee radios passing data with one being a 7 dbi rubber duckie on a UAV at 600 feet and the other end being a 24 dbi grid antenna on the ground with clear line of sight at 10 miles.

    Old Man Earl
  • BigFootBigFoot Posts: 259
    edited 2009-07-31 20:03
    @earl:

    Weren't you telling me that you lived out in the desert near Phoenix ? We were talking in the hotel
    the morning after the Propeller Conference.

    Russ
  • 4Alex4Alex Posts: 119
    edited 2009-07-31 20:32
    @Earl:

    Oh dear, oh dear, oh dear. Calm down. I didn't meant to ruffle your feathers. Assumptions were using XBee to XBee, as provided through DigiKey or SparkFun, as per microcontrolled 'as cheap as possible' requirements. In that type of configuration, you simply don't achieve very long range. My comments are in line with all the other posters on this, it seems. You did mention using a yagi, so I simply asked you about the setup. No offence intended, really. Now I hope this gets you off you high horse (so to speak) and thank you very much for answering my rather esssentially technical questions. BTW I see no major feat achieving 600 feet using 60mW XBees, clear LOS rural. And yes dear, I do have some knowledge of RF (~25yrs). But this isn't a contest for the most grey hair, or is it?

    Cheers,

    Alex
  • Ole Man EarlOle Man Earl Posts: 262
    edited 2009-08-01 00:43
    OK, horse back in barn...I don't know why I got so ruffled. Must be getting old and crotchety.

    @Russ No, I line in desert 75 mi SE of ABQ,NM
  • BigFootBigFoot Posts: 259
    edited 2009-08-02 23:35
    @Earl, I think X-Bee and its associated mesh network concept is really cool, and plan to have
    my whole house running on it soon. We just felt that the X-Stream modules were better suited
    for our application.

    We make PoS terminals for school cafeterias and needed to be able to say sell hot dogs out on
    the football field. The terminal can then transmit the data back to our transaction server on the
    schools network and deduct the cost from the students account. Parents fill the account over
    the internet and then have a record of exactly what there kids are eating.

    Russ
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2009-08-03 00:12
    Re "I am on limited budget and the total product cannot have more then $80 of stuff on it."

    That might not be possible. But you could get close. I've been working on a wireless mesh project for the last two years. It is not simple and I have a whole shelf in the shed filled with failed RF experiments and projects. That inludes hacked audio walkie talkies, hacked radio controlled toys, hacked long range (1 watt) video transmitters and multiple experiments with antennas from 1Mhz to 2.4Ghz. Then there are experiments which did work but which turned out to be illegal.

    Right now, I'm working with these modules www.yishi.net.cn/rf/ProductShow.asp?ID=98

    I've got several kilometres through trees and not a direct line of sight, so there is potential to boost that with yagis with only a few elements.

    Cost was about $40 each - so there goes the budget. But they do replace a wired connection very easily. I went for the lowest baud rate because lower rates = longer range. Also, these modules have a -123db receiver sensitivity which is quite an amazing number.

    There are quite a number of modules around - I went for the Yishi ones because they can handle placket sizes of up to 256 bytes wheras most modules are only 32 bytes. Xmodem can then be used to transfer files/pictures etc. I have xmodem working on CP/M boards and very soon will have it working on Cluso/Heater's zicog prop emulation. So then it would be a prop+RF module project. Still might be difficult to get <$150 though.

    Post Edited (Dr_Acula (James Moxham)) : 8/3/2009 12:51:54 AM GMT
  • Carl HayesCarl Hayes Posts: 841
    edited 2009-08-03 01:01
    Dr_Acula (James Moxham) said...
    I went for the Yishi ones because they can handle placket sizes of up to 256 bytes
    Fascinating -- the application must have been a remote-control sewing machine -- turn.gif

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    · -- Carl, nn5i@arrl.net
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2009-08-03 01:13
    It is perhaps timely that PhiPi's Bell Modem thread is active at the moment, because there is potential to use existing audio transceivers and do all the audio processing/filtering etc inside the propeller.
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