radio link planning made easy with a telegram botwireless.ictp.it/school_2017/slides/rfbot.pdf ·...
TRANSCRIPT
Radio Link Planning made easy with a Telegram BotMarco Zennaro (ICTP), Marco Rainone (Solvitech), Ermanno Pietrosemoli (ICTP)
© ICTP, 2017 1
Is this link feasible?— Anonymous
© ICTP, 2017 2
RF Planning tools
Options:
— Commercial tools (expensive, heavy downloads, PC only)
— Vendor tools (limited to specific models, web interface, free)
— Free tools (only point to area, no attenuation, etc)
© ICTP, 2017 3
RadioMobile
Pros:
— online
— well documented
— many users
Cons:
— steep learning curve
— no mobile version
— heavy maps© ICTP, 2017 4
Splat!, an open source RF planning tool
— Signal Propagation, Loss, And Terrain Analysis
— open source Linux based tool, GNU license
— SRTM3 digital elevation maps (DEM) at 90m resolution
— Longley-Rice Irregular Terrain Model (20 MHz to 20 GHz)
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Telegram and Telegram Bot
— Telegram is a cloud-based instant messaging service
— smartphones (Android, iOS, Windows Phone, Ubuntu Touch) and desktops (Windows, OSX, Linux)
— In June 2015, Telegram launched a platform for third-party developers to create Bots
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BotRf usage
Add BotRf to your contacts
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BotRf usage
Add the working frequency in Mhz with the Freq command.
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BotRf usage
Add the first site with the command
site mountain_1 -4.3409 55.7450 5
where mountain_1 is the name of the site, -4.3409 is the latitude in decimal degrees, 55.7450 is the longitude in decimal degrees, and 5 is the height of the antenna above the ground in meters
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BotRf usage
Add the second site with the command
site mountain_2 -4.6205 55.4413 16
where mountain_2 is the name of the site, -4.6205 is the latitude in decimal degrees, 55.4413 is the longitude in decimal degrees, and 16 is the height of the antenna above the ground in meters
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BotRf usage
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BotRf usage
To check if the path is clear or obstructed from the radio signal viewpoint, use the calc command. Enter
calc mountain_1 mountain_2
to check the link between the two sites, at the frequency you previously selected.
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BotRf usage
— The brown line is the curvature of the earth, modified by the refraction index.
— The green line is the terrain profile.
— In blue we have the optical line of sight.
— The magenta line is the 60% of the first Fresnel zone.
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BotRf commands
— ant mountain_1 30 will change the antenna height of the site called mountain_1 to 30 meters
— you can ask for help to the Bot using the /hlp command
— rep in BotRF produces an extensive text report
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Extensive text report
Transmitter site: edif_admSite location: 8.5931 N / 71.1469 WElevation: 1582 m above sea levelAntenna height: 50 m above groundDistance to plan morro: 12.52 kmAzimuth to plan morro: 221.3 degreesElevation: +3.1degrees
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Extensive text report
Receiver site: plan_morroSite location: 8.5086 N / 71.2221 WElevation: 2311 m above sea levelAntenna height: 6 m above groundAzimuth to edif_adm: 41.3 degreesDepression angle: -3.2 degrees
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Extensive text report
Free space path loss: 129.69 dBLongley-Rice path loss: 129.55 dBAttenuation due to terrain shielding: -0.13 dBMode of propagation: Line-Of-SightThe first Fresnel zone is clear.
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Link budget calculation
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Link budget calculation
The pow command in BotRf is used to obtain the power levels in the link.
pow edif_adm plan_morro 20 0 24 24 0 -87
transmitter site, receiver site, TX power output in dBm, TX cable loss in dB, gain of the TX antenna in dBi , gain of the RX antenna in dBi, RX cable loss in dB and receiver sensitivity in dBm
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Link budget calculation
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Exercise
Using the LoPy IoT node from pycom.io, check if a IoT long link between ICTP and Muggia is possible.
Use 868 MHz as frequency, 10 dBm as output power and -134 dB as sensitivity of the radio.
You can use two 4 dB antennas.
Find suitable sites on both ends.
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LoPy device
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LoPy device
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Thanks
We thank ISOC-Internet Society for their support.
Contact info: [email protected]
Website: http://wireless.ictp.it
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