Hi All,
I'm new around here and just began to set up my emon system in my house. I've run in to some complications that I'm sure others have encountered as well. I've seen partial answers distributed across the forums. So I guess the first question is whether there's a good single page the covers all the related issues of the following.
See background at bottom.
Questions:
Are transmissions sent every 10 seconds?
What are the challenges that could explain them not being received every 10 seconds?
What tricks are available to boost signal strength?
How can I have measure RSSI (signal strengths) given that emonHub doesn't seem to display these?
What tricks are available to avoid collisions?
What tricks are available to bring the TX's or the TX's antenna's closer to each other? (longer CT wires? picking up currents outside the circuit panels?)
How should the antennas be oriented?
Does the emonBase antenna need to be straight?
Can changing the power sources improve signal strength?
Is there another way to connect the TX's to the base that might improve the connection? (ex. USB?, Ethernet?)
Background: In my open basement I have a main circuit panel and a subpanel about 12 meters apart. I have a emonTX on each panel, with four CT's on each. The red light on the TX's flashes approx. every 10 seconds. Each TX is powered AC/AC (USA voltages). Each has the antenna provided by OEM Shop. -- My system is 433MHz. -- The emonBase is powered by USB and is near the main panel. It's got an antenna wire sticking out.
I'm looking at my local EmonHub Nodes page and notice that although it seems the TX's are trying to update every 10 seconds, occasionally one or both will miss an update. This can be frustrating if the I'm monitoring something like a well pump that isn't active for very long. This was much more prevalent with the (more distant) subpanel TX, but that improved somewhat when I moved the base a bit less distant from the subpanel TX.
See my fairly generic FAQ'ish questions above inspired by my background situation.
Thanks
Re: Distance, protocols, antennas, poll rate...
"Are transmissions sent every 10 seconds?"
Normally, yes, but it can easily be changed in the sketch.
"What are the challenges that could explain them not being received every 10 seconds?"
That could be down to interference from other devices, or from other equipment that should not (but does) transmit in the band.
"What tricks are available to boost signal strength?"
There are no tricks. There are, however, some well-established techniques: You can add a ground plane, or use an antenna with gain (i.e. directional).
"How can I have measure RSSI (signal strengths) given that emonHub doesn't seem to display these?"
It's available in the log, or you can use Minicom to see it http://openenergymonitor.org/emon/modules/emonpi#ssh
"What tricks are available to avoid collisions?"
Not a trick: Transmit shorter messages less frequently.
"What tricks are available to bring the TX's or the TX's antenna's closer to each other? (longer CT wires? picking up currents outside the circuit panels?)"
Again, these are not tricks. You could extend the antenna cable, you could extend the CT & VT cables. Or you could move into a smaller house.
"How should the antennas be oriented?"
They need to be at right angles to the line of sight, and parallel to each other.
"Does the emonBase antenna need to be straight?"
Yes.
"Can changing the power sources improve signal strength?"
No - unless there is something wrong with the power source anyway.
"Is there another way to connect the TX's to the base that might improve the connection? (ex. USB?, Ethernet?)"
You can use a serial connection - but I can't say what distance you might achieve.