Newbie questions, link planning, path loss, fresnel zones etc

Support
1

Hi,

I’m new to the project and just learning the ropes. I have working client and router nodes and can establish communications for few kilometer link spans.

I got few specific questions regarding the design and implementation of a network.

Link planning

When doing real world deployment, if I have LOS between nodes, how important really is the 1st fresnel clearance? Since the link budget is in the realm of 150-170 dB, which is insane, one would think that some “minor” path loss doesnt really matter.

Also in this regard, currently I’m thinking that link spans of 10-20 km or at maximum 30 km is reasonable without very high placed antennas or other ground clearance (due to fresnel restrictions). Is this so in practice? If using 30-50 meter hilltops, I calculated that you should get F1 clearances for atleast 10 km paths.

Testing connectivity and link quality

When using android client with identical node setup everywhere (with encryption keys and all), is there other way to test connectivity other than “request location” from the menu? In meshtastic cli I can get more data with --info and --nodes and --sendping

If node is in repeater mode (with all_skip_decoding), is there any way to confirm/measure node functionality/visibility?

If you have been, thank you for reading.

2

I don’t think the fresnel zone is a big issue in practical links over land because reflections are mostly unpredictable. When calculating a link over water like a sea or a big lake you may be effected by it.

For testing connectivity you can send a ‘direct message’ to a certain node. If you see the ‘personlike’ symbol you have good connectivity. If you get the ‘cloudlike’ symbol you can not be sure if the message was received.

3

Thanks for the info. As it happens, my longest link is 23 km over sea. This gives largest radius of 45 meters. The antennas are at 50 and 23 meters from sea level. I think this is enough for 60% F1 clearance.