Cumulus Support

Hi,

I have a N96GY and it's been working fine for the past 10 months. Last night however, the console stopped receiving the data from the transmitter.

The temperature/humidity sensor is still transmitting (I can hear it on my scanner radio and SDR), but I make it to be 433.887.5MHz, not 433.9 that the sticker on the back says. Anyone else able to verify this for me?

Thanks

I was under the impression it was 433.92MHz, which is used by many systems.

Possibly you also can hear a signal on 433.90 MHz? If so, I suspect the transmitter is not using standard 5 KHz narrow band FM bandwidth. Could be using a 10-15 Khz wide or even wider channel. If it is, being off 12.5 KHz wouldn't be a problem. A wide band signal makes it harder to hear the telemetry if your scanner can only receive narrow band UHF communications. I'm just speculating here, of course.

Does your SDR have a scope function? If so, can you "see" the N96GY signal?

Also, 433 MHz is a fairly common frequency for remote control devices. Could some other device be interfering with or perhaps jamming the signal?

--Kurt

Hi,

The (present) Maplin branded versions don't use narrow-band FM but simple OOK (On-Off-Keying) which will have a much wider bandwidth. See this thread for example. The receiver probably just uses a Surface Wave Filter which may have a bandwidth in the tens if not hundreds of kHz, so local interference from another "433.92" ISM transmitter is a definite possibility.

Interestingly, the (868MHz) Clas Ohlson branded version, and also "early" Maplin stations, do appear to use a more sophisticated FM wireless channel.

Cheers, Alan.

Thanks all for the replies and suggestions.

So, on the same day as the weather station stopped receiving the signal, my car refused to unlock via keyfob unless I was right up against the window *and* pointing in towards the rear view mirror. My wife's car was ok, perhaps it doesn't use 433MHz!

A couple of days later I was able to lock my car remotely from inside the house again, and when I checked the weather station console, it was receiving again!

Perhaps there was a strong local 433-ish signal (or a harmonic of 433-ish) was affecting all these devices, although none of the radios showed anything like that. Very odd!

Kurt: yes I can see the signal blip in the SDR waterfall.

As a side note, I was very surprised at the amount of devices I was able to listen to around 433.92 when I used my Yaesu and switched to Digi mode. Might be fun to try and decode them with the SDR and rtl_433.

Andy