N96GY tx freq?

[tbninja]

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

[logjam]

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

[N0BGS]

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

[AllyCat]

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.

[tbninja]

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