[Boatanchors] Voltage Calibrator

[David C. Hallam]

John,

Actually I suppose I have little use for the VTVM.  I would just like to 
know it is working properly.  I have a DVM that I use for most 
measurements.  When I am tuning circuits for peaks and dips, I usually 
use my scope with a frequency counter attached to the vertical output.  
That way I can see the peak or dip and the frequency at the same time.

73
David
KW4DH

On 12/29/2011 11:53 AM, J. Forster wrote:
> Good idea.
>
> You can buy a new 3 1/2 digit DMM for<$20. That should be good to better
> than 1%, certainly good enough for a VTVM cal, DC, AC, and Ohms.
>
> And, you might find you like the DMM better than the VTVM, except for
> tuning to peaks or dips.
>
> Best,
>
> -John
>
> ===========
>
>
>
>
>> How about a variable power supply, then put a DVM (digital Voltmeter)
>> whose accuracy you trust, in parallel with your VTVM across the power
>> supply.  Even a cheaper idea, depending on how high you want the
>> Voltage, if you're talking Voltages in the hundreds, snag the B+ from a
>> receiver, put a high value pot across it, then your parallel VTVM/DVM
>> across that.  MOST VTVM calibrations that I remember only had one
>> adjustment that affected all ranges, depending on the 1% resistors in
>> the divider to set the rest.  From what I remember, typically they
>> (Heathkit etc) used a NEW 1.5VDC D cell for calibration purposes and had
>> a mark on the meter for the "calibration point". Now with DVMs we have
>> much more affordable 'accurate' ways, and the usual DVM can be read much
>> closer than the analog dial of a meter.  So, it makes sense to use the
>> DVM as a "standard".
>>
>> Hope this helps you.
>>
>> 73 de Phil,  KO6BB
>> http://ko6bb1.multiply.com/ (OTR Blog)
>> http://www.qsl.net/ko6bb/  (Web Page)
>>
>> RADIOS:
>> Grundigs: Satellit 750 (2011), S-350 (2006)&    G6 (2011).
>> Kenwood: TS130S Transceiver (circa 1980).
>> Radio Shack: DX-380 digital portable (circa 1990).
>> Yaesu: Two FT-8800 Mobiles, VX8R Quad-Band (circa 2010).
>> Zenith: Royal-7000 Transoceanic (circa 1969).
>>
>> ACCESSORIES: MFJ 1040C Pre-Selector, W9GR Audio DSP.
>> ANTENNA: 88' Long Ladder-line fed dipole, Apex at 35 feet.
>>
>> Central California
>>
>>
>> On 12/29/2011 4:27 PM, David C. Hallam wrote:
>>> What is a good DC voltage source that doesn't cost big bucks to use to
>>> calibrate a VTVM?  I can't afford several hundred dollars for a piece of
>>> test equipment with such limited use as a voltage calibration source.
>>>
>>> David
>>> KW4DH
>>>
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>
>

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