On Mon, 9 Nov 2015 16:58:10 -0500, "Ralph Mowery"
wrote:


"KenK" wrote in message
...

I just bought a new Accurite indoor/outdoor thermometer to try to get
accurate readings. It differed by 2 deg at about 40 this morning with a
few
year old identical thermo. Yesterday I put those two, an ancient home
thermo and a refrigerator thermo (all I had) side by side at about 70. The
readings varied from 67 to 74. Is this about par for the course? I'd
really
like to find one I can believe. I've had bad luck with Accurite digitsl
thermos and wind indicators in the past so didn't try another one.

Sugestions or is it hopeless to expect more than 2 to 3% accuracy? Or
perhaps I shouldn't care?


Go to a store that has a lot of them on display and pick one that matches
the majority of them.

When I was working I did a lot of instrument calibration and we had a
temperature bath we could put things in. It was calibrated every year to
about .1% by a calibration lab.
About 10 years ago I brought home an old digital readout and matching
thermocouple that I had calibrated to match at 100 deg F.

I looked at that and compaired it to other thermometers around the house.

The calibrated one was showing 67.1, another was showing 68. I have an
elcheapo digital I bought off ebay that has 2 thermocouples for it. They
were showing 65.5 and 65.8

A company that made thermocouples for us set aside a large spool of TC wire
and all ours were suspose to be made from that wire. We used them by the
hundreds or more. We did not need to know exectally what the temperature was
on the process, but it needed to be repeatable from year to year. Most of
the temperatuers were from about 260 to 300 deg C. The TCs we got were
suspose to be within 2 deg C at 300 deg C.

The products we made was polyester that went out looking like a bale of
cotton and string for things like tire cord.
We made over a million pounds of each every day when te plant ws running at
full capacity.

I wonder how long it will be before clocks get wireless Internet
capability for local forecast? I bet having a wireless web receiver
wouldn't cost anymore than the external sensor.

That is basically what this is:
http://www.monoprice.com/Product?p_i...FZQ6gQoda2sMeQ

97% percent accuracy is plenty good enough for me. I would be
interested in reasons where that is not close enough.