I had some old remote control 433mHz sockets that had marginal reception due to their old design and metal speaker stands blocking transmission.
After messing about moving the transmitter and finding a location where all the sockets were working reliably I'd find that moving the transmitter (e.g. when dusting the room or moving furniture slightly) was enough to make some of the receivers marginal.
I knew my transmitter used a PCB mount coil antenna and that was fine for new remote sockets that were a long way away but the problem was some older sockets IN THE SAME ROOM as the transmitter!
I saw this great guide (Download the PDF) and used some old wire the BT engineer had left in the street outside. I used a small watchmakers screwdriver, some paper and wire cutters. I soldered in my home made antenna and now the marginal sockets all work fine - no need to find a sweetspot for the transmitter as it seems to work anywhere in the room
https://www.instructables.com/id/433-MHz-Coil-loaded-antenna/
After messing about moving the transmitter and finding a location where all the sockets were working reliably I'd find that moving the transmitter (e.g. when dusting the room or moving furniture slightly) was enough to make some of the receivers marginal.
I knew my transmitter used a PCB mount coil antenna and that was fine for new remote sockets that were a long way away but the problem was some older sockets IN THE SAME ROOM as the transmitter!
I saw this great guide (Download the PDF) and used some old wire the BT engineer had left in the street outside. I used a small watchmakers screwdriver, some paper and wire cutters. I soldered in my home made antenna and now the marginal sockets all work fine - no need to find a sweetspot for the transmitter as it seems to work anywhere in the room
https://www.instructables.com/id/433-MHz-Coil-loaded-antenna/