Remote thermo/humid sensor disconnecting

[justaguy]

I have a TFA-Dostmann weather station that has worked fine for years, but recently started to suffer from random disconnects with the external thermo/humid sensor.
When the signal is lost, the only way is to reset the base station and then it works for some days, before disconnecting again.
Of course could be just random RF noise from the neighborhood, but I think some component may have degraded over time (it´s about 10 years old).
I have checked the obvious on both TX and RX sides, but unfortunately I lack RF tools (and experience); I only have a 100MHz scope and a RTL_SDR compatible dongle. With that one, I confirmed the transmitter is sending out pulses at levels comparable with other transmitters at about 433.85MHz.


On the receiving side I don´t really know what to check...

I´m wondering if the oscillator in the RX module needs to be tuned, and how can I do that with the limited equipment that I have?
Any brilliant idea before I toss it in the bin?

[CosteC]

Batteries are obvious thing, but those you probably checked.
De-tuning 433 TX or RX is an option. Probably more TX as it is outside, exposed to elements.
on photos I do not see corrosion, so it shall be fine.

Maybe your dongle can measure up to 433 to check frequency?

[justaguy]

Yes, with the dongle I see the TX signal at about 433.85MHz. Playing with the variable inductor on the TX module moves the frequency up and down by about 50KHz and the power up and down a bit, I tried to tune it where the signal seems to come out stronger but it´s far from an accurate measurement.
Batteries have been replaced.

[CosteC]

I tried to tune it where the signal seems to come out stronger but it´s far from an accurate measurement.

Unfortunately you need to tune it to receiver frequency not to maximum power. Not sure can it be done other way than blindly adjust to see receiver receiving.. Maybe RF people can help?