Anyone remember Metricom?
900mhz, miles of range, dial-up modem speeds.
LoRa Range Testing in San Francisco
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Re: LoRa Range Testing in San Francisco
#12I'd like to see how it does in rural areas. There's a gap in the market for GPS horse trackers because you can't count on any particular communications network, unless you use licensed amateur radio APRS.
Rural areas would generally be much better due to the lower number of objects in the way. Now, that will give you less options for bouncing signals, but supposedly, you can achieve ~13 miles with line of sight.
My rural area (the northern frontier of Appalachian mountain range) doesn't have long lines of sight. Around here the high points are around 2000 ft above sea level and most of the population is in a network of valleys that dissect what would otherwise be a plane. Hilltops are wooded too (even on the many hills named "Bald Hill") so you have to add another 40 ft to your tower just to look into two adjacent valleys.
If, on the other hand, this hardware mounted on one of my buildings can cover my 70 acre farm and a bit of the valley around it, I could find a use for it.
Re: LoRa Range Testing in San Francisco
#13Anyone remember Metricom? 900mhz, miles of range, dial-up modem speeds.
Yes, yes indeed. Changed my life in 1998 when I no longer had to be in the office when on Pager Duty. Just velcroed a ricochet modem to my laptop and I was good to go from anywhere. We kind of take that convenience for granted these days.
Re: LoRa Range Testing in San Francisco
#14If you are curious about tropospheric ducting this[1] site shows openings determined by looking at what packets are coming through APRS igateways. Some of the LoRa stuff runs on UHF so it could be subject to similar openings(like the huge one over the midwestern US right now.
Re: LoRa Range Testing in San Francisco
#15I wonder what the frequency of operation is -- 315, 433 or 869 MHz?
Shawn from Beep here. We use the 902-928MHz band in the US.
Re: LoRa Range Testing in San Francisco
#16Earlier quoted context omitted.
Rural areas would generally be much better due to the lower number of objects in the way. Now, that will give you less options for bouncing signals, but supposedly, you can achieve ~13 miles with line of sight.
My rural area (the northern frontier of Appalachian mountain range) doesn't have long lines of sight. Around here the high points are around 2000 ft above sea level and most of the population is in a network of valleys that dissect what would otherwise be a plane. Hilltops are wooded too (even on the many hills named "Bald Hill") so you have to add another 40 ft to your tower just to look into two adjacent valleys. I…
Sounds like an interesting challenge. Hit us up if you'd like to try out Beep's kit -- daniel at beepnetworks dot com.
Re: LoRa Range Testing in San Francisco
#17There are limitation to do with the Duty Cycles in LoRa networks which we've found inhibits certain real time applications. It effectively limits the number of "messages" you can send during a specific time frame.
True in Europe (CE) but it works differently in the US (FCC).
The FCC limits time spent transmitting in a single channel ("time on air"), but there's no duty cycle limit if you follow the channel hopping rules.
Re: LoRa Range Testing in San Francisco
#18There are limitation to do with the Duty Cycles in LoRa networks which we've found inhibits certain real time applications. It effectively limits the number of "messages" you can send during a specific time frame.
Shawn from Beep here. Are you referring to LoRaWAN networks specifically? I'm always down to talk wireless schemes. Hit me up (email in my profile).
We go beyond LoRaWAN with our own protocol for some use cases.
For those following along: LoRa is a wireless encoding technique (PHY layer), LoRaWAN is a protocol for how a large group of devices should structure their packets (MAC layer).
Re: LoRa Range Testing in San Francisco
#19Directionality. If you have a single gateway with tons of power for tx, is it ultra sensitive for RX and what the requirements on the end devices from a power perspective?
Yes -137dBm sensitivity: http://www.semtech.com/wireless-rf/rf-transceivers/sx1272/
In the blog post we were using 27dBm transmissions. At that level the radio and power amplifier draw about 1.5W. If a transmission takes .3seconds that's .5Watt-seconds. So with a single AA battery (about 5Wh) you can do 40000 transmissions.
Transmissions can be much shorter in time depending on radio parameters, by a factor of 32 at most, but range can be affected.
Re: LoRa Range Testing in San Francisco
#20If you are curious about tropospheric ducting this[1] site shows openings determined by looking at what packets are coming through APRS igateways. Some of the LoRa stuff runs on UHF so it could be subject to similar openings(like the huge one over the midwestern US right now. [1] http://aprs.mountainlake.k12.mn.us/
Troop is not going to be so strong as it is in 2 meter (140-144 MHz) band but 900 can bounce strongly off meteor trails, the moon, etc. Reflections off airplanes could be a big deal too.
Sporadic long range channels could be a bug and not a feature for this kind of system because if you are not a ham who thinks it is a blast to talk to someone 500 miles away on a a handheld, you want a radio system to work predictably and not be interfered with by distant stations.