Photon + XBee Digi MESH


#61

Hello, greetings from Brazil. I am planning to work with these modules + 6 dbi antennas to cover a radius of ~ 500m in an urban area. It’s possible? Do these models with wire antennas have good range in outdoor (in-town) environments? Thank you!


#62

They should be able to do that easily if you get the antennas up as high as possible and or have a decent mesh network setup.


#63

Thank you RWB! I think that I can put the antennas at a height of 5 m. But if it does not work, it is possible to put it at 30 m (with the disadvantage of needing to insert another unit in the network)


#64

5 meters should be plenty and should allow 1 mike range easily with the 900HP radios.

I can get 1 mile range with the radios 5 feet above ground level in a dense single story neighborhood.


#65

I made some tests, but I’m not able to reach more than 0,43 miles :frowning: I’m using 6 dbi monopole antennas. Should I use dipole antennas?


#66

Do you have theTX power level set to 10?

I’m not sure about antennas, I was using omni directional antennas.


#67

PL (TX Power Level) is set as Highest [4]. I do not have the option to go up to 10, only up to 4 :thinking:


#68

PL = 4 is the Highest.
image

@LeoBR, which XBee radio (hardware version) are you using ?


#69

Hi @Rftop . I’m using a XBP9B-DMWT firmware version 8075


#70

Well, I bought the dev kit. I’m impressed with the range of wire antennas (~300m/0,19 miles in my neighborhood)

My hardware has the 200k version. I’ll install 10k firmware and put the XBee to work in repeater mode. According the datasheet, the range should be improved with 10k version.

I’ll put the results here ASAP. Maybe this experience with XBee help someone :smile:


#71

@LeoBR, I’ve found that the max “expected” distance doesn’t play a large role in the design of any particular project. It’s driven by the specific local environment, as it relates to the 900MHz RF signal.

In a typical MESH topology layout, we’re looking for multiple available routes from each router/repeater Node (it needs several Neighbors). The local physical conditions dictate this, much more than the “expected” range. My “As-Built” location maps never resemble my “Design” Maps, so I don’t even bother anymore. During deployment, run XCTU in the field and watch your RSSI values to determine the proper locations and adjust as necessary.

In short: We generally install many more routers/repeaters than is required by the Point-To-Point range of the radios, to establish the multiple available routes through the MESH. This would also apply to a Gen3 MESH.


#72

The 10K firmware should extend your range some. Let us know how that works out for you.

Just keep testing using the XCTU software and pay attention to the RSSI numbers. The height of the Antenna and obstructions play a big role in the range.


#73

Hi! I just performed the tests with the 10k firmware. I got 952 m (0,59 miles). It isn’t a bad result at all… but should be better. I’ll buy some dipole antennas to check. There a lot of houses in my neighborhood, but I was expected at least 1 mile :face_with_raised_eyebrow:


#74

That’s close to the .77 miles I was getting with the Antenna at 4 foot height.

You can see the signal was traveling down a straight road and didn’t have to pass through every single house like in your example.

Getting the antenna up above all the obstructions is the key :key:.

XBee does make some 1 watt radios which are 4x the power of the 900HP radios but they cost $100 each.


#75

You’re right, @RWB. I didn’t realize that in your case above has less obstacles. I have a lot of trees in the signal line too (and almost all are pretty tall).
I saw these 1-watt radios, but yes they are very expensive. XBee-PRO 900HP proved to be a viable and certified alternative. :smile:

Ah, I’m using this kind of antenna. Maybe a have a signal loss due the 5 m cable… But as I need to put the modules inside a metal enclosure, I need a long cable anyway.


#76

Feed line loss can be significant, especially as frequency goes up. Perhaps check that the antenna / cable are well assembled, try no to “kink” coaxial cable when routing. I’ve used XBee on ~915MHz and 2.4 GHz. Feed line losses (especially in the case of low cost solution) can be significant, perhaps 3db for low quality. Is the cable marked / of known quality? Usually it’s an antenna solution that saves the day not raw power. My guess is that you are able to get that 0.77mi shot, perhaps not fastest rates, but I have made it much farther. Look forward to hearing of your success.

Best Regards, _Todd
de KB2GGS