Fine Offset station protection

[sdalrymple]

I purchased a Fine Offset (WH1080 base, WH14C transmitter) from Klaus Ohslen a year ago. Last week it stopped transmitting (or maybe receiving?), the red LED showing permanently, I trawled the forums and tried everything suggested, changed batteries, unplugged everything, changed cables.. but unfortunately nothing seemed to work.

I am right on the coast here so suspected that continued exposure to the salty air might have caused a fault somewhere?

I also noticed that Klaus Ohlsen have a 2 year warranty, and rather brilliantly, they have sent me an identical replacement!

I've opened up the transmitter on the old one, and nothing looks immediately damaged, rusty, salt encrusted. How can I find out what caused the fault, and how can I protect the new one from suffering the same fate?

[philcdav]

It might be interesting to find out if the device is transmitting>

Either grab a local radio amateur, who may have the kit, or get an SDR TV dongle (£10) and check the frequency for a signal using a PC.

Otherwise you would need a scope to check values.

[AllyCat]

Hi,

Yes, salt corrosion in your location is certainly a possibility, but if the exposed metal surfaces look ok, then that's less likely to be the problem. You could coat the circuit board and components with varnish or a commercial PCB treatment, but must NOT get it on/into the humidity sensor, nor any connnector/contacts, so it's probably not worthwhile.

Is the red LED still on permanently when the batteries are inserted? That implies that the microcontroller has "hung" or "crashed", instead of proceeding through its normal measurement/transmit/sleep cycle. It may or may not actually be transmitting, but you might be able to determine that by measuring the battery drain with a multimeter. Anything over about 10 mA would suggest that the transmitter is powered, which should have a duration of only around 100 ms every 48 seconds (so is quite difficult to check with CW test gear). The Clas Ohlson stations use 868 MHz of course; does the Console have the (new) blue backlight? That was the point, I believe, when they changed from the original (FSK) wireless protocol to the "new" (OOK) protocol.

Cheers, Alan.

[uncle_bob]

how can I protect the new one from suffering the same fate?

Probably the best protection you can have (from endless frustration) is enclosing both the receiver and transmitter units in one of these type of enclosures.



Then use the sensors with a WeatherDuino system. That what I did and haven't looked back.