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Fine Offset and derivatives.

Posted: Sun 30 Dec 2012 4:14 pm
by northumbria
Bought from Maplins a couple of months ago, £59.99 and all that. The kit is about as I expected but the barometer is quite bizzare. I realised quite soon that the barometer drifts, it's up and down as mearsured against a precission instrument and is more than my late professional experience would accept. The drift seems, almost diurnal and, possibly, moon connected. I've been checking this against a Greisinger GTD1100, which gives readings, spot on, commensurate with local METARS and with NULL checks against height AMSL. Any ideas ? I guess like you, I wouldn't want to 'round out' too high or too low.

Re: Fine Offset and derivatives.

Posted: Sun 30 Dec 2012 5:02 pm
by AllyCat
northumbria wrote:The drift seems, almost diurnal
Hi,

It depends what level of accuracy/error you're expecting, but AFAIR two people have recently reported that the barometric pressure of their FO station actually "tracked" another parameter (internal temperature?). In these cases the station (Console) was deemed to be faulty and returned/replaced by the supplier. Sorry, I can't find the relevant threads ATM, perhaps they were described under a more generic "fault" topic.

Cheers, Alan.

Re: Fine Offset and derivatives.

Posted: Sun 30 Dec 2012 5:09 pm
by steve

Re: Fine Offset and derivatives.

Posted: Sun 30 Dec 2012 5:51 pm
by northumbria
AllyCat wrote:
northumbria wrote:The drift seems, almost diurnal
Hi,

It depends what level of accuracy/error you're expecting, but AFAIR two people have recently reported that the barometric pressure of their FO station actually "tracked" another parameter (internal temperature?). In these cases the station (Console) was deemed to be faulty and returned/replaced by the supplier. Sorry, I can't find the relevant threads ATM, perhaps they were described under a more generic "fault" topic.

Cheers, Alan.
Thanks Alan,

I have my 'reference' on the same windowsill as the Maplin console which houses the barometer, they are both subject to like atmospheric conditions. Perhaps I'm a little 'paranoid' but, maybe experiencing something new (to me). I don't know what type of barometer the 'Maplin' has, I suspect that it's a very basic aneroid and subject to the ups and downs of atmospheric pressure but, why does it drift so ? If you have a barometer on your wall at home, would you expect it to overread by .7 mb and then to underread by the same amount a few hours later? Sorry but I have a professional 'thing' about QNH, QFE, QNE, height, altitude and flight level. I realise that I've given those as a list but I do know that they each have different meanings.