I found many antenna advertised as "GSM/CDMA cellular antenna" over at sunsky-online. Looking at their specs, they seems to work in the XBee range. Might be a good piece to extend Xbee range if you could connect them together.
One particular thing I found is this "repeater".
Can someone chime in wether this is usable in the ground-end of the Xbee? I am interested in getting more range out of my serial modem but can't afford the XTend.
GSM900 Cellular Phone Signal Repeater Booster + Antenna
1) Frequency range: a) Up link: GSM 890-915/DCS 1710-1785(MHZ); b) Downlink: GSM 935~960/DCS 1805~1880(MHZ)
2) Gain(dB): GSM/DCS: >50/55/60/70
3) Output power (dBm):<10/17/20/27
4) Stray radiation: <=-36
5) Latency: <=5usec
6) Standing wave: <=1.5
7) Power supply: AC200V/DC9V
8) Interface Type: N-K
9) Noise factor: <=5dB
10) Impedance: 50ohm
11) Booster size: Approx. 197x105x32mm
12) Weight: 538g
13) Coverage: 100 meters
* Antenna speciation:
1) Frequency range: 900~1800MHZ
2) Product size: Approx. 39x20x2.5cm
3) Cable Length：10m
4) Weight: 811g
Replies
In a word, no! First of all there is a discrepency in frequencies, the Xbee works on 868Mhz, the above equipment works in the 900Mhz GSM band, it just wont see the signal, also the Xbee uses a different protocol to GSM so even if they were on the right frequency, the GSM equipment would simply ignore the Xbee.
The same with using GSM aerials, the 900Mhz ones are some 20Mhz off tune, a significant amount to increase the VSWR the Xbee would see, in short the receive gain would drop, and the effective radiated power (erp) from the aerial would decrease as well.
I have over 33 years experience in amateur radio, a lot of it on high frequencies 400Mhz to 10Ghz. You would be really surprised just how far you can get with very little power, if you are using high gain and well matched aerials, the world record for transmission between a laptop wifi and another computer's wifi using STANDARD equipment is 380Km from ground to a hot air balloon. If we assume your Xbee is 10Mw, using the correct aerials will dramatically increase the gain, and therefore the distance. The average modeller can make his own, using the tools he has, its not rocket science. I myself have managed almost 10 miles using bluetooth class II (10Mw) and a couple of ex satellite dishes, but dishes are extremely hard to point at your UAV
The simple answer is to use a Yagi aerial similar to the above, but a bit bigger and a higher gain aerial in the UAV
If you want more help or info, send me a PM
John