My suspicions were triggered by the comment that the unit appeared to work for 5 minutes and then stopped. This might suggest that something else is transmitting during that period and confusing the decoder in the receiver. It is very unlikely to be your doorbell, for while this also works on the same frequency, it only transmits when the bell push is pressed. More likely is a burglar alarm system or central heating controller, both of which transmit a periodic keep alive signal, as do some old people fall alert transmitters.
The distance between the remote and the base may only be relivent if the signal between them is very weak, as this might lead to reception of a partially complete message.
Equipment of this type have a number of different strategies for dealing with signal interference, some just ignore badly formated messages, others will attempt to decode them. The problem comes when the interference message is partly decoded, as the next valid message is also partly decoded and the base unit hangs while it waits for the message to be completed. A further fault of this kind is when the system power saves by synchronises with the valid messages, expecting the next to arrive a predetermined period after the first. A single jamming signal decode can result in a permanent lose of sync. A fault I have noted on some of the Oregon weather stations, which can be disrupted by a single misplaced decode of an RF doorbell press. Such faults can only be cleared by resetting the receiver allowing it to resync with all the remote transmitters.
Without access to test equipment, the only sure way to eliminate the possibility of RF interference is to move the equipment to a new site, far away, and see if it starts working.
I have equipment that can monitor this and other control frequencies. Just listening to the decodes on and around 433.92MHz, you would be surprised how much traffic is transmitted with short blips to long buzzing messages. The equipment on this license free channel has an effective range of 30m, but can be detected at a much greater range, depending on the receiver and aerial used.
One other suggestion to consider:
Have you noticed the remote unit battery life is shorter than normal?
This could indicate that one of the sensors has failed or has a poor connection, resulting in the remote going into continuous transmit mode.
Statistics: Posted by NigelJ — Wed Mar 02, 2016 1:43 pm