"gw" wrote in message
m...
Chuck Harris wrote in message
...
gw wrote:
Chuck Harris wrote in message
...

-Chuck, WA3UQV

does that mean you still have some use for trash 80's?


Way too new! I'm more interested in old PDP 8, stuff, 8/I's
in particular. Things that have absolutely no practical use ;-)

-Chuck

perhaps one of you guys can tell me this. when you see a unit on ebay
and it says fresh calibration, what exactly does this mean to me as
the buyer? does this mean it will probably be operating ok for a few
years or is this something that has to be done yearly? for the home
shop hobbyist ? thanks.

A commercial calibration implies no warranty of future reliability. It just
means that the unit was inspected, by a lab with traceable standards (to
NIST), and that equipment parameters were found to be within the specified
tolerances (or some adjustments we made to allow for proper performance).

Every equipment should be on a periodic schedule of calibration, possibly 6
months or 12 months. The interval is determined by the original
manufacturer's declaration, or from the class of equipment (is it a resistor
or a function generator or an oscilloscope), or from the accumulated record
of a device's calibration history. (A Metrology professional can make a case
for shorter or longer intervals, based on a review of the calibration
history.)

The calibration is valid as of that date only, although it's reasonable to
expect that the calibration will be valid for some time to come (unless the
shipper dropped it as it went out the cal lab's door!).

All that said, a traceable calibration is an indication that the equipment
has been treated in a professional manner, and I would view that as a
definite plus when considering a purchase.


Ed
WB6WSN