One of our members has a PowerBeam aimed at a 120° a few miles away. We're using Ch. 184. He'd like to put a Rocket + Omni, also on Ch 184 to allow others to connect to the mesh through him. He wonders if there is a minimum separation between the two on his tower? Or should he remove the PB-M5-400, using only the Rocket+Omni (13dB)?
Theme by Danetsoft and Danang Probo Sayekti inspired by Maksimer
Trying to share the channel will limit the systems data capacity, since both 'cell' sites several miles apart are receiving signals from each other. The RF space is shared across both locations and this means that generally only 1 mesh node anywhere will be xmitting at a time to avoid colliding on the channel and more data re-transmitted. With these hidden node concerns, the mesh nodes will use RTS/CTS handshaking to coordinate and avoid these collisions and working to only have 1 mesh node transmit at a time. If the 2 cell site's coverage is on 2 different channels then each cell site can pass traffic independently to achieve 2x or more overall capacity--it scales better and lowers latency.
It would be very difficult if even possible at some sites to separate or isolate 2 mesh nodes on the same tower so that they do not receive each other's signals (both on the same channel). I don't even bother trying, rather ensure they do hear each other so that the RTS/CTS handshaking is communicating effectively. If this handshaking is loosing packets, then more packet collisions and retrys would be expected--would be worse.
To put the Rocket-omni on a different channel means there needs to be a network switch configured so the Rocket and PBE can route traffic between them over the cat5 cable on the DtDlink or vlan2 network. This separates the traffic for any laptop, camera, etc. that obtains an IP address from one of the mesh nodes.
In the ideal world, with money growing on trees in the back yard to help, there would be 3 channels in use. It's not the band in use that is significant, it's the usage of a unique and available quality channel. 3Ghz for P2P links means the higher cost of 3Ghz equipment is incurred by a few people. 3Ghz on a cell coverage area means more people are paying higher cost to do the same thing vs 2Ghz or 5Ghz. The 3 unique channels would be:
1) cell coverage at site A
2) cell coverage at site B
3) Point to point link between sites A & B
Joe AE6XE
I have a tunnel to Redlands, CA and a PB on CH.184 feeding a Rocket+120° covering the town (and Lake Havasu). We have three other hams with nodes, all on CH.184. Tom would like to extend the Mesh to the north of town, which is where the Omni idea comes in. Here in town we'd like to stick to one frequency.
When we extend to other cities (Bullhead City / Laughlin and Kingman), we'll use multiple frequencies, and maybe rob some convenience stores to afford 3.4ghz links, but that's likely a year or two away.