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We are currently working on a project using 3 XBee modules. One is like a data center or the master of the other two XBees.

We did a range test with a master and a slave XBee on an open field using a router antenna which is 3 dBi and is dipole. The distance we had was roughly 30 meters from the master. We ordered an omnidirectional 7 dBi car antenna with 2.5 meters wire length and again repeated our range test using it. The result was better but we just reached 800 meters.

Our project needs to get about 15 km. Will we be able to obtain it? We tried using an RF amplifier but it doesn't seem to work well with XBee modules. I have read articles/forums on the internet that uses a 2.5 dBi dipole antenna and they are able to obtain kilometer values on their range test. I don't know where we went wrong. I did my research but I cannot reach our desired output.

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  • \$\begingroup\$ Do you have a clear line of sight? \$\endgroup\$ – Chris Fernandez Feb 12 at 13:35
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    \$\begingroup\$ @ChrisFernandez Yes. we did it in an open field. No buildings to block. It was done in a reclaimed area. \$\endgroup\$ – jee cuevas Feb 12 at 13:38
  • \$\begingroup\$ "router antenna which is 3 dBi and is dipole" by router antenna do you mean you pulled an antenna off a wifi router? it's my understanding that the length of the dipole is supposed to be half the wavelength, which would explain the poor performance. \$\endgroup\$ – aidanh010 Feb 15 at 5:58
  • \$\begingroup\$ @aidanh010 hi. sorry what I meant with a router antenna is the antenna with the same jack of common routers in my place. but to be specific, it is a rp-sma jack antenna. Yes that is correct but what makes me think is why articles on other xbee projects used dipole antenna and are able to reach 4km so why cant we? its kinda tricky \$\endgroup\$ – jee cuevas Feb 16 at 14:56
  • \$\begingroup\$ @jeecuevas Unless that antenna was designed to work at 900 MHZ band, it will perform poorly. The RP-SMA connector means that it will "work" and connect at all, not well. Dipole refers to it being split into two sections, as opposed to a monopole which uses the metal of the PCB in lieu of the other pole. The type of dipole that has been FCC approved for use with the 900HP and is sold by Digi is a half-wavelength dipole. If it is not the same length, it will not perform correctly, dipole or not. If it was say a WiFi or cellular half-wave dipole, it will be half of a different wavelength. \$\endgroup\$ – aidanh010 Feb 16 at 22:43

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