Weather station wireless sensor

Hi all,

My sensor has decided to pack up when the temperature drops below about

7C. It's very difficult to tell what's occuring as trying to locate the faulty component/s with freezer on these SMD boards is almost impossible. The led still pulses but nothing is received even re-registering doesn't work until the RF section warms up again. It's not the crystal or the SAW device (I think that's what it is) as both these when cold don't stop it from working.

I've tried to monitor the transmissions on a receiver at 433.92MHz but I think these devices use some sort of frequency spread/shift modulation and I can't pick up a carrier of any sort, even when it's working? Anybody got any experience with these things?

Happy new Year to all Bob

Reply to
bob
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Reply to
Mike Berger

It's probably the batteries, mine tends to drop out at cold temperatures when the batteries start to get a bit weak.

Reply to
James Sweet

Hi,

The batteries are OK. I actually measured them outside in the frost! Must be mad.

Reply to
bob

What are you talking about? Your description of your problem presumes that we can read your mind and know exactly what you have. What kind of weather station? What kind of sensor? What's the circuit it's connected into? What kind of transmitter and receiver are you using? What is being re-registered? and how?

You gonna have to release a lot more info before you get any meaningful help.

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in 
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Reply to
DaveM

Fair comment I supose. I did think these units were pretty much generic but maybe not, anyway here goes. The Weather station is made by RF Tech model 65R05 and the sensor just reports the temperature. Circuit it's connected into? Not sure what you mean but the receiver unit displays inside/outside temp, humidity and pressure. All I can tell you about the TX & Rx is they work on 433.92MHz according to the docs. The registering process is done by pressing reset buttons on both devices. When it works you see a symbol flash on the Rx LCD screen and it bleeps, then the outside temp is displayed. What happens is once the temp of the Tx unit drops below about 7C the RX unit doesn't receive the signal. I've tried monitoring the frequency on a Yaesu FT50R at 433.92 and there's nothing there even when it's working?? I do however manage to pick up some cross mod on a nearby carrier and can hear the data stream when it transmits. This happens even when the RX unit has lost the signal?

Happy New Year Bob

Reply to
bob

I have installed a device to measure the wind speed ( my design) that freezes when the temperature is below 0c. To preventing from freezing I have installed a halogen lamp under the unit that comes on when the environment is below 2 degrees C. I know that isn't a wireless solution but may be a solution.

John

Reply to
Canfree

Your transmitter is probably drifting off frequency as the temperature goes lower. Probably not much you can do about it other than contact the vendor that sold the unit to you and ask for a replacement or refund. Alternatively, contact the manufacturer, if you can find them, and ask for assistance, whether it be repair, replacement or refund. My guess on the whole affair is that you will probably get no satisfaction from anybody. I googled for RF Tech weather station and hit on this link to

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which contains a significant number of complaints similar to yours, but no evidence that the company is responding to any of them.

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in 
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Reply to
DaveM

Thanks for that Dave, interesting on the web site although it's not the actual maufacturer? This things over a year old now so it looks like it could be destined for the bin, shame but I thought it would give me an opportunity to see how it works (or doesn't in my case)! I agree with you about the frequency shift. Trouble is being as I can't find a carrier as such, and that you can't set it to transmit permanently, it's pretty much impossible to fault on. I wonder how they set them up in the factory?

Cheers Bob

Reply to
bob

Getting back to the RF-Tech, I've fixed it. After drawing out the RF part of the circuit I found that the one transistor oscillator was controlled from it's emitter by a switching transistor which in turn was controlled by the data stream. This had a bad connection and consequently the rf osc was not even turning on. If anyone wants anymore details drop me a line. (I've already posted this once but it appears to have got lost?)

Bob

Reply to
bob

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