Cumulus Support

Indoor test rig results are good

I'm satisfied with the testing so I'll be installing the same modification outdoors today when I have time. The indoor plot shows the temperature cycling from the room thermostat nicely.

I've now finished testing and have moved the test rig and connected it to my outdoor transmitter and CAT5 cable up the mast. I've disabled to test transmitter by taking the batteries out and resynchronised the second console to the outdoor transmission. So the 48 second logging computer is now reading real data.

I started building a tidier opto-coupler unit for outside using the RJ11 cable from outdoors but I found the yellow wire was loose in the RJ11 plug so decided to simply move the test unit outdoors. I'll make up a proper damp-proof version later if the test unit works alright. Meanwhile, I'm wondering if some of my problems have been due to a badly made lead all along! This is the one supplied with the station. Evidently the cable crimping in the plug was faulty.

thats a very nice temp.plot
the faulty crimping could be the cause,when the cable was moved by wind,it could have made it on/off/on/off......
but could also have been the connector on the pcb.
( hopefully thats water under the bridge)

will wait for your results afterwards,but looks good.

Well... Not a total success yet but I do have a coil of excess CAT5 cable in the Stevenson screen box and the test rig is not the most tidy arrangement. And we know the transmitter unit is VERY sensitive to anything untidy! I'll see if I can find the time to tidy it up tomorrow - we have a fair amount of outdoor work to do now the frost has gone and before the next lot!! Anyway, here it is - temperature plot for last couple of hours (roughly).At least it isn't a hedgehog!

More data. Showing a remarkable regularity except for the longer period at the beginning.

Being a mild evening, I decided to take a look at my outdoor setup. I've managed to tidy it up a bit and I've put the coil of spare cable on the roof of the Stevenson screen. So it's now a few inches away from the Tx unit rather than about an inch behind it. When I get time in daylight I'll cut the cable to length and reconnect the wires.

send it to SETI@arecibo,they go nuts

very regular indeed,looks timer operated

SETI is a good thought

Here's the latest... Seems like a change - time will tell, but the regular spikes seem to have stopped. The "bump" jusrt after 19:00 is the heat from my hand when I held the Tx unit.

So far so good - getting a feeling of deja vu!

I believe I have some answers as to the causes of spikes now. The electric fence was off overnight and back on just before 09:00 this morning. While the fence was off and after I'd tidied up a bit, there were no spikes but as soon as the electric fence came on there was a large spike and there have been several since. So I surmise - two causes of the spikes, one was the effect of a longer cable on the anemometer circuit and the other interference from the electric fence. The opto-isolator has successfully isolated the cable from the transmitter anemometer circuit and I conclude that the anemometer/cable problem is solved.

Some might find the passive termination of the cable with the series RC across the anemometer sufficient to cure the anemometer problem but an opto-isolator (opto-coupler) really does make sure.

Curing the electric fence interference remains. I doubt I'll have time to sort that out today.

Hi Gina
Having been an RF engineer for many years
if you are picking up the spikes from an electric fence your cables may be acting as an antenna
try if possible to feed you cables from the sensors down thru the middle of the mast then ground the pole to a copper stake or similar this should create a Faraday shield around your cables, worth a try
but if the spikes are being generated by the reed switches this will not help
you could try a snubber say 100R and 0.1uf
ROY

Orion wrote:Hi Gina
Having been an RF engineer for many years
if you are picking up the spikes from an electric fence your cables may be acting as an antenna
try if possible to feed you cables from the sensors down thru the middle of the mast then ground the pole to a copper stake or similar this should create a Faraday shield around your cables, worth a try

That is precisely what I intend doing, possibly this afternoon. Not only will the metal mast screen the cable but will also keep UV rays off the cable (which is not the outdoor rated variety).

but if the spikes are being generated by the reed switches this will not help
you could try a snubber say 100R and 0.1uf.

There is already a 100 ohm and 470nF across the reed switch as in your diagram, but thank you for the suggestions Roy

Also will stop the goats chewing them

Orion wrote:Also will stop the goats chewing them

Very true I could do with a pipe from the rain gauge to the screen for the same reasons. Copper water pipe would do. NOT plastic