The 2.4Ghz modules may be heading up to $36, but the cost of 900Mhz access will be going down in 2009. All the way down to $39 for a 900Mhz module which is upgraded to 115200 baud but range reduced to 1.8 miles.http://www.digi.com/products/wireless/zigbee-mesh/xbee-digimesh-900.jsphttp://www.digi.com/products/wireless/point-multipoint/xbee-pro-900.jspIt will be 5V tolerant on the UART pins, but you better keep those voltage dividers around until 2009. The $32 XBees are not 5V tolerant & quickly burned out if U followed the social network hits on Google that said they were.
Not as cheap as last year, but finally U North Americans have an affordable 900Mhz radio. Unfortunately, our income tax went up by over 4 XBee's so forget about seeing XBee PRO 900's on this blog.
Jack - I know it is already 2009, but I work for Digi and would be happy to return your call or email regarding XBee modules. Please feel free to email me at justin.ferguson@digi.com.
I didn't realize the XBee Pro 900 wasn't yet shipping. I talked with one of the Digi engineers last week about actual end-to-end throughput of the module, and half-duplex delivered bitrate without hops is in the 90-100kbps range. This is pretty good - the best we saw with the 2.4GHz version was 80kbps.
The Meshnetics ZigBit 900 may be shipping, and they claim a 1Mbps wire rate, but their numbers aren't real - the actual throughput is currently limited to 38.4k with hoped to reach 57.6k via new firmware in January. However, if you don't need the higher throughput, that might be an option.
Wonder if anyone has succeeded in getting an XBee-Pro 900 out of digi.com before our predicted delivery date of 2009. They don't return phone calls & there's still no online ordering for it. It seems the 2.4Ghz band is too dangerous anywhere near Silicon Valley. 900Mhz is on the roadmap again.
Thanks James. I'm using 2.4Ghz Xbee Pro's at the moment. The 900Mhz versions are not available in Australia. I just hadn't thought about the 900Mhz version causing more inteference due to it being closer to the L1 frequency.
Marty, the GPS L1 frequency is 1575.42 MHz, so it's closer to 900 MHz than 2.4 Ghz, but not by a whole lot. All electronic devices are going to emit some electromagnetic radiation. It's difficult to predict what is going to work. You might have problems either way, so you just have to deal with them.
I've seen a 1 watt 900 MHz radio work fine on a UAV system (these XBee Pros are 50 mW). I've seen a 1.4 GHz Pentium processor from an onboard computer cause interference with the GPS. The fix involved moving the GPS antenna aft and a bit of carbon fiber shielding.
P.S. I just got a confirmation email from Digi saying my stuff was shipped this morning.
Decided to forget about 900Mhz again. Ordering is going to be painful until 2009 & there's interference with GPS. U have to put a certain distance between the 900Mhz radios & GPS & that is a high risk item on a micro copter.
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Not as cheap as last year, but finally U North Americans have an affordable 900Mhz radio. Unfortunately, our income tax went up by over 4 XBee's so forget about seeing XBee PRO 900's on this blog.
Happy Hew Year!
The Meshnetics ZigBit 900 may be shipping, and they claim a 1Mbps wire rate, but their numbers aren't real - the actual throughput is currently limited to 38.4k with hoped to reach 57.6k via new firmware in January. However, if you don't need the higher throughput, that might be an option.
I've seen a 1 watt 900 MHz radio work fine on a UAV system (these XBee Pros are 50 mW). I've seen a 1.4 GHz Pentium processor from an onboard computer cause interference with the GPS. The fix involved moving the GPS antenna aft and a bit of carbon fiber shielding.
P.S. I just got a confirmation email from Digi saying my stuff was shipped this morning.
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