Radio Link Planning made easy with a Telegram BotMarco Zennaro (ICTP), Marco Rainone (Solvitech), Ermanno Pietrosemoli (ICTP)

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Is this link feasible?— Anonymous

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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)

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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: mzennaro@ictp.it

Website: http://wireless.ictp.it

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