Pressure varations with temperature

[Philip]

Hi to all

I have now moved my weather station ( maplin ) to the middle of a field, the base station and a dell laptop are now located in a very well ventilated barn.

During the recent days of nearly steady pressure it has become apparent that the inside temperature and the pressure graphs look very similar. At the same time of the move I also changed to cumulus 1.9.1. I never noticed this similarity before when the base station was in our house.

Has anybody else seen this with either the new software or base station temperature changes?

If you want to have a look at my weather graphs they are at:-

http://www.jollyroger2.eclipse.co.uk/weather/

light winds and blue skies


Philip

[steve]

The pressure reading will vary a little with temperature, particularly with a station that has no compensation like the Fine Offset. But I think you have a problem with your pressure sensor; I'm pretty sure I've seen a case like this before, where someone's pressure sensor was actually following the inside temperature.

I'm reasonably confident that it isn't a problem with Cumulus, but you can check this simply by comparing the relative pressure reading on the console with the reading shown by Cumulus.

[Philip]

Steve

Thanks for the quick reply, I was hoping you weren't going to say that I will check on Saturday when I am next in the field and report back.

Philip

[steve]

I found a couple of past threads where Fine Offset owners had pressure graphs which closely followed the shape of the inside temperature graph, as yours does, but in neither case did the owner come back later to say what, if anything, they had done to resolve the problem.

[robynfali]

mine doesn't

http://www.h-i-r.org.uk/weather/trends.php


But it would be handy to know if there is a problem solved, should an issue arise!

[Gina]

Mine doesn't either. I agree that it would be helpful to others if people would post if they find the cause of a problem and say how they solved it.

[Philip]

Just a quick update. It is the pressure/temperature sensor that is faulty, I removed the covers and applied a little heat from a hair drier the pressure reading immediately changed. One of the soldered joints looked a little dry so I resoldered them all but to no effect.

The sensor looks like a HP01S from hopeRF ( http://www.hoperf.com/upfile/HP01S.pdf ) so all I have to do now is find a supplier.

Watch this space

Philip

[simonvfr]

I have the same problem Philip, so I am looking forward to hearing whether you are successful in replacing the sensor.

[Philip]

I have good news and bad news.

First the good news; my weather station is now back up and running and showing the correct data.

Now the bad news I have got nowhere in my search for a pressure/temperature sensor. So I have bought a new system from the UK weather store on ebay ( item number 110680441123 ). I was near Sudbury so I called in to their office and collected it; very pleasant and helpful people, knew their subject and very efficient. I was on my way in no time. At £64.50, a better price than Maplin, and as a bonus it also has a radio controled clock.

A word of warning: all the Easy Weather stations use either 433 or 868Mhz radio links and thus are not 100% compatiable with each other although the external sensors are.

I now have spare external sensors which I can modify and improve at my leisure. I have not given up on finding a new sensor and will keep looking and email AGAIN the company in China.

Blue skies and light winds

Philip