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Zigbee freq for least 2m / GPS interference
Dan Bowen
#8760 Hi All, Thanks, Dan 4 |
BASE
#8766 Dan, We have used MaxStream (now Digi??) XBee Pro operating at 2.4 GHz with no problem for any of our radios (typically some version of Byonics MicroTrak) or GPS (Garmin 18). In some cases, all three devices are in a single styrofoam box. We also have flown a configuration that has the XBee Pro, Garmin 18 and a FreeWave 900 MHz spread spectrum unit in the same box. I have never experienced any problems with interference or de-sensing. Howard, KC9QBN BASE-DePauw toggle quoted messageShow quoted text --- On Sun, 10/31/10, Dan Bowen wrote:
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Stephen Meer
#8767 Dan, I echo Howard’s experience. I have flown both high and lowpower level Digi ZigBee 2 GHz modules that were mounted within 1” of GarminGPS-15 and uBlox GPS units (and within 3” of their antennas) without difficultyfor over 5 flights. In all cases I used ZigBee units with integral antennas,both the patch and wire version. Based on bench tests and field use I havealso not seen any indication of 2M receive sensitivity loss in the presence of 2GHz ZigBee either. I utilize pretty standard foam core compartmented enclosures. Ido however place a mu-metal foil shield between the compartment housing the GPSantenna on the top of the payload and the lower compartments housing the restof the gear. No fancy feed through for the GPS coax is used. I got into thishabit from my 433 MHz balloon-bus days where I did have issue with GPS receiverinterference which was ultimately traced to the 433 MHz getting into the GPSantenna internal preamp. In the past I have had to resolve interesting 2M birdies generatedfrom my serial data lines within the payloads so I would suggest checking forthose carefully. /s/Stephen, K0SCC EOSS :GPSL@... [mailto:GPSL@...] On Behalf Of DanBowen Hi All, Thanks, Dan 4 |
Dan Bowen
#8772 Thanks guys, that's great information!! Thanks, Dan toggle quoted messageShow quoted text On Nov 1, 2010, at 11:56 AM, Meer, Stephen wrote:
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Bill Brown WB8ELK
#8787 Dan, Last August I flew a 100 milliwatt Zigbee PRO XSC unit on 915 MHz sittingabout 6 inches from my Inventek GPS board and I saw no desense problems...in fact I managed to get quite a few direct to ground telemetry strings from the Zigbee unit in the balloon using it's rubber duck antenna to my 8 dBi patch antenna and another Zigbee PRO unit on the ground from over 20 miles away....and in it's worse antennapattern for the balloon since I was directly underneath it while it was 20 miles above me. - Bill WB8ELK toggle quoted messageShow quoted text -----Original Message----- Thanks guys, that's great information!! Thanks, Dan On Nov 1, 2010, at 11:56 AM, Meer, Stephen wrote: Dan, I echo Howard’s experience. I have flown both high and low power level Digi ZigBee 2 GHz modules that were mounted within 1” of Garmin GPS-15 and uBlox GPS units (and within 3” of their antennas) without difficulty for over 5 flights. In all cases I used ZigBee units with integral antennas, both the patch and wire version. Based on bench tests and field use I have also not seen any indication of 2M receive sensitivity loss in the presence of 2 GHz ZigBee either. I utilize pretty standard foam core compartmented enclosures. I do however place a mu-metal foil shield between the compartment housing the GPS antenna on the top of the payload and the lower compartments housing the rest of the gear. No fancy feed through for the GPS coax is used. I got into this habit from my 433 MHz balloon-bus days where I did have issue with GPS receiver interference which was ultimately traced to the 433 MHz getting into the GPS antenna internal preamp. In the past I have had to resolve interesting 2M birdies generated from my serial data lines within the payloads so I would suggest checking for those carefully. /s/Stephen, K0SCC EOSS : GPSL@... [mailto:GPSL@...] On Behalf Of Dan Bowen Hi All, Thanks, Dan 4 |
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