[ARC5] Meter Calibration

[Fuqua, Bill L]

  To calibrate an analog meter you only need 2 digits of precision, not even the full 3.5. 
  I have been teaching a class called the "Radio Theory and Construction Workshop" for over 10 years now.
Students are provided a radio kit, additional parts, tools and instruments. 
I have purchased well  over100 of these meters and amazingly enough had no failures and they are very good for 
the price. They go on sale from time to time mostly because they have batteries in them which have limited shelf
life. If you are calibrating an analog meter these are more than accurate enough. 
 Mind you, in most cases you are lucky to do better than a few percent accuracy when using an analog meter.
In most cases, at a glance, probably no better than 3%  even if the meter is well calibrated. We have been spoiled
by the digital ones just as we have been by digital calculators instead of slide rules.
 In the old days if you made measurements with an analog meter and did some calculations with a slide rule you were
lucky to get results better than 10%. Especially if there were a number of calculations performed. 
  I had a friend that had be away from ham radio for sometime and got back into it. He got a more modern digital 
dial radio but wanted to build up his old station, a  SX110, VF-1 and DX20. After he got these his old station built up
he just could not use it effectively and did not like it. He was spoiled by the modern radio and just could not go
back to the old ways.  He sold the boatanchor stuff. 
73
Bill wa4lav



________________________________________
From: wb3fau55 at neo.rr.com [wb3fau55 at neo.rr.com]
Sent: Saturday, August 03, 2013 7:26 AM
To: Glen Zook; Brooke Clarke; Fuqua, Bill L; arc5 at mailman.qth.net
Subject: Re: [ARC5] Meter Calibration

inexpensive meter?- you  get what you pay for
---- "Fuqua wrote:
>    I have checked these  Harbor Freight meters as well.
> The input resistance is disappointing but they are better than 1 percent compared to
> a much more expensive meter.
> 73
> Bill wa4lav
>
> ________________________________________
> From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on behalf of Glen Zook [gzook at yahoo.com]
> Sent: Friday, August 02, 2013 9:39 PM
> To: Brooke Clarke; arc5 at mailman.qth.net
> Subject: Re: [ARC5] Meter Calibration
>
> I bought this relatively inexpensive DMM from Harbor Freight:
>
> http://www.harborfreight.com/5-in-1-digital-multimeter-98674.html
>
>
> "Just in case" I were to have problems with my Fluke.  The meter reads within less than 1% of what I read on my considerably more expensive Fluke!
>
> I did get it "on sale" for like $34.95 a few months ago.
>
> The quality of things bought at Harbor Freight range from absolutely junk to pretty darn good!  One has to look at the item and make a determination of the quality.  Fortunately, there is a Harbor Freight outlet about 5-miles from my house which does allow me to look at the item before purchasing.
>
> I also have several of the Harbor Freight "red" DMM units that are often on sale for as little as $1.99 each at the local store.  For "quick" measurements the accuracy is fairly good.  Not as good as my Fluke, but, good enough to see if things are working properly.  Besides, if I happen to blow one up (haven't done so this far, but there is always a possibility), at $1.99 each, I haven't lost any real money.
>
> I generally keep one of these "red" DMMs in each tool box, in the glove compartment of my car, etc.
>
> Glen, K9STH
>
>
> Website:  http://k9sth.com
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