GarageMote interfering with Garage Opener Remotes

[Tony Weil]

I recently added a GarageMote (915Mhz), which work great, to my 2009 Liftmaster Garage Opener (315Mhz). I noticed that the garage remotes, with new batteries, that came with the garage have a significantly reduced range when the GarageMote is powered on. With the GarageMote powered off, the remotes work at least 150' away and around the corner of the house. With the GarageMote powered on the remotes won't work any further than 55'. I moved the GarageMote from the back of the Garage Opener to the top which got me from 30' to the current 55', but the antennas are still about a foot apart.

I suppose I could try to lengthen the GarageMote wires and move it further away. The GarageMote reads -72db at the Pi Gateway. so I suppose I could reduce the transmit power on the GarageMote.

Has anyone seen this problem and can suggest a solution? It doesn't make sense since a) the GarageMote and "Garage remotes"  run at such different frequencies and b) The GarageMote is not always transmitting, so why is it interfering ALL the time?

[Felix]

I don't know of anyone else having so much trouble with their particular garage opener brand/model as you have 
But IMHO on this particular issue, I would consider it a slight benefit (added security perhaps? ).

Anyway it makes no sense but maybe others have extra input on this.
First the frequencies are different, then the fact that the Moteino RFM module is in receive mode all the time (except when it transmits a status change or an ACK), so I don't see where is any RF interference between the 2.

I suppose I could try to lengthen the GarageMote wires and move it further away. The GarageMote reads -72db at the Pi Gateway. so I suppose I could reduce the transmit power on the GarageMote.

At the very least use RFM69_ATC which should automatically dial down TRANSMIT power only, this is a good practice on any transmitting mote - only transmit as "loud" as necessary, "louder" is pointless and a waste of power especially on battery powered nodes.
If you can try a longer cable ... it won't hurt to see the effect. I would probably try the same thing myself. I wonder if any other EMI interaction or the proximity of the magnets has anything to do with this...

How about this...I recall you had lots of issues with the actual connections to the opener itself.
Try disconnecting power to the GarageMote but do not disconnect it from the opener. Then see if the range issues persist, if YES then something is wrong with the opener and it just won't like anything else connected to the terminal intended for the wall-attached opener button.

[Tony Weil]

But IMHO on this particular issue, I would consider it a slight benefit (added security perhaps? ).

This is more a curiosity than a problem. It will only be a problem when my wife presses the remote button from too far away and it doesn't work. I've instructed her on the "new" procedure. We'll see.   

At the very least use RFM69_ATC which should automatically dial down TRANSMIT power only, this is a good practice on any transmitting mote - only transmit as "loud" as necessary, "louder" is pointless and a waste of power especially on battery powered nodes.

Running the stock GarageMote sketch. ATC_RSSI is on and set to -75. How low can I set it?

How about this...I recall you had lots of issues with the actual connections to the opener itself.
Try disconnecting power to the GarageMote but do not disconnect it from the opener. Then see if the range issues persist, if YES then something is wrong with the opener and it just won't like anything else connected to the terminal intended for the wall-attached opener button.

In my previous tests, I did just unplug the power and leave the connections to the garage opener.

[Kilo95]

i believe the garage door opener is using just a receive antenna. what if you used a shielded coax, connected center conductor to where the current garage door opener antenna is on the motor, and ran it a few feet away. you could then strip the end of the coax off to leave the center conductor. My thought is maybe that would shield it enough to help.

[Felix]

Running the stock GarageMote sketch. ATC_RSSI is on and set to -75. How low can I set it?

-100 is the weakest signal, -50 would be among the very strongest.
So you want to be quiet enough but not too quiet that say if some obstacle suddenly is introduced, then the signal can't get through.
-75 gives a very generous safe margin, but I think I run most my motes on -80 tp -85. Even -90 would be pretty safe in most cases.