Propagation notes

Getting from here to there-how and why
Two terms will show up if you are looking at nodes on your device, or more useful, one of the local meshsense stations:
RSSI: received signal strength (how loud do I hear you)
SNR: signal to noise radio (how noisy are the surroundings: library or noisy street)The best metaphor for SNR I think is talking to someone in the shower: you can hear them (high signal, low noise) while they cannot hear you (same signal, high noise).There is also a phenomenon called "de-sensing" which means if a radio is transmitting near another radio, the gain (sensitivity) of the second unit is automatically decreased (AGC or automatic gain control)What does this mean for your project?
keep nodes that are not actively repeating mesh traffic in client-mute mode, meaning they hear but do not repeat
make sure any node in repeater/router mode cannot directly "see" another repeater, as they will simply echo each other
careful placement of repeaters and routers is critical: both repeat all traffic, so using router-late is a good option if you are not sure: it delays the repeating until another can respond
the only difference between repeater and router is the former does not show up on mapsAntennas:See the article listed on the home page for a detailed account of different antennas.General thoughts:
Most antennas used are vertical quarter wave omni antennas or "whip" antennas
Higher performance antennas look like these, but are actually dipole antennas
Make a larger dipole, arrange it like a fish skeleton and you have a yagi antenna or yagi-uda beam antenna (n.b. yagi is "goat" in Japanese)
As a general rule, the longer the vertical omni antenna, the more disk-like is the horizontal propagation patternIn my experience, mesh follows many paths, and using a yagi may seem like a great way to extend range, but be careful that the polarization of the antenna is setup correctly: 905 mHz uses vertical polarization, so any yagi should look like vertical elements to be useful.
Migrated from Apple Server Wiki. Original page ID: i543A9