On Tue, 13 Dec 2011 06:42:55 -0800, Winston
wrote:

Hul Tytus wrote:
alt.machines.cnc, rec.crafts.metalworking
Harbor Freight electronic calipers warning

Three recently bought electronic calipers from Harbor Freight turn
themselves off after a few minutes of inactivity. Some turn on again if moved
(12 in version), the others (8 in version) need be manually restarted. The 8
in. one shows zero when turned on& the 12 in restarts with some of the same
numbers but not all. bleep, bleep, bleep. Anyone zeroing calipers on a
reference and expecting that to hold longer than a minute or two need find a
source other than Harbor Freight.

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.

--
However beautiful the strategy, you should occasionally look at the results.
-- Sir Winston Churchill

Larry Jaques wrote:
On Tue, 13 Dec 2011 06:42:55 -0800,
wrote:

(...)

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.

Nah just nearfield magnetic flux.

--Winston

Larry Jaques wrote:

Winston wrote:

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.



Sigh. 'Prolly' the comment of a know it all.

The RFI is caused by the circuitry rectifying the RF, and injecting
noise into the analog portions on the equipment. At RF levels high
enough to affect the digital portion can destroy the equipment. A
fluorescent light generates noise well past 4 GHz. I used to use the
one on my bench to test C-band LNAs, LNBs & LNCs before I got a
calibrated C-band signal generator. Simply holding one end of a signal
diode and connecting a voltmeter between the other end and earth (Safety
ground) will show you how much energy is wasted as RF in fluorescent
lights. I made a test fixture to sort thousands of small signal diodes
by output voltage about 40 years ago. The ones with the highest output
gave the highest sensitivity as a detector. I tossed the worst, and used
the rest for diode logic circuits.


--
You can't have a sense of humor, if you have no sense.

On Tue, 13 Dec 2011 12:20:32 -0800, Winston
wrote:

Larry Jaques wrote:
On Tue, 13 Dec 2011 06:42:55 -0800,
wrote:

(...)

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.

Nah just nearfield magnetic flux.

Are we sure it couldn't be moist, fluoridated humidifier air causing
the problem? Maybe a little more would wash away that flux.

--
However beautiful the strategy, you should occasionally look at the results.
-- Sir Winston Churchill

Larry Jaques wrote:
On Tue, 13 Dec 2011 12:20:32 -0800,
wrote:

Larry Jaques wrote:
On Tue, 13 Dec 2011 06:42:55 -0800,
wrote:

(...)

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.

Nah just nearfield magnetic flux.

Are we sure it couldn't be moist, fluoridated humidifier air causing
the problem? Maybe a little more would wash away that flux.

Wash it away?
I was gonna store it in a flux capacitor.

--Winston

On Tue, 13 Dec 2011 21:05:17 -0800, Winston
wrote:

Larry Jaques wrote:
On Tue, 13 Dec 2011 12:20:32 -0800,
wrote:

Larry Jaques wrote:
On Tue, 13 Dec 2011 06:42:55 -0800,
wrote:

(...)

Also beware that HF digital calipers tend to be very
susceptible to RFI. If I put my cheapo plastic
calipers next to a fluorescent fixture, they go all
wonky until placed well away.

Prolly the plastic conducting sunspot activity.

Nah just nearfield magnetic flux.

Are we sure it couldn't be moist, fluoridated humidifier air causing
the problem? Maybe a little more would wash away that flux.

Wash it away?
I was gonna store it in a flux capacitor.

What? You got Doc to sell one to you? Have any spares? And for that
matter, do you have any spare DeLoreans? Or a Mr. Fusion? The latter
would be my absolute favorite choice.

Goodbye, plugging in your electric car every night.

--
However beautiful the strategy, you should occasionally look at the results.
-- Sir Winston Churchill

On Dec 15, 7:15*am, "J. Clarke" wrote:


You want more hot air or water? Use more collectors.

I want hot air at 2 AM. *How many collectors will I need to get that?

Not a big problem except for making it cost effective. Phase change
material can store the heat until needed.

Dan

wrote in message
...
On Dec 15, 7:15 am, "J. Clarke" wrote:


You want more hot air or water? Use more collectors.

I want hot air at 2 AM. How many collectors will I need to get that?

Not a big problem except for making it cost effective. Phase change
material can store the heat until needed.

Dan

IIRC around here the advice is that 5 acres of carefully managed
"collectors" will keep your house warm, up to 20 if you just take whatever
falls on the ground. The collectors are cheap and mostly maintain themselves
but property taxes can be a killer.

jsw