[volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left

Tue Sep 2 08:40:52 EDT 2014

thanks, I would welcome comments on calibration too.

> Gesendet: Dienstag, 02. September 2014 um 12:23 Uhr
> Von: "Stephen Grady" <grady.steve at gmail.com>
> An: "'Discussion of precise voltage measurement'" <volt-nuts at febo.com>
> Betreff: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
>
> The Datron 4920M was a special version of the 4920 made for the military, the major difference is the M version has a 50 Ohm (N-female) wideband input and only the N-female input for the low frequency input. Whereas the 4920 has a Binding Post Input as well as the N-female input. I am not aware of the specs for the wideband input but the low frequency input will be the same for both models.
> 
> I intend to reply in some detail soon on the calibration of these instruments (and this will also apply to the Fluke 5790) and the principals of AC calibration below 100mV as Charles has raised the issue of using attenuators to do lower voltage measurements.
> 
> Kind Regards,
> 
> Stephen Grady
> Sydney, Australia
> 
> -----Original Message-----
> From: volt-nuts [mailto:volt-nuts-bounces at febo.com] On Behalf Of acbern at gmx.de
> Sent: Tuesday, 2 September 2014 5:54 PM
> To: Discussion of precise voltage measurement
> Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left
> 
> folks,
> 
> does anybody know the difference in specs between a 4920M and the standard 4920. No data on the web.
> 
> thanks
> 
> 
> 
> > Gesendet: Sonntag, 31. August 2014 um 23:41 Uhr
> > Von: "Charles Black" <cblack at centurytel.net>
> > An: "Discussion of precise voltage measurement" <volt-nuts at febo.com>
> > Betreff: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay 
> > - 1 day left
> >
> > Hi Stephen,
> > 
> > Thanks for the info on the 4920M. It might be that I should pass on 
> > this but it is nice to know that it is probably working. If I don't 
> > have the necessary items needed for calibration it might still be a 
> > good source uncalibrated.
> > 
> > I was hoping that the 4920 had better minimum voltage out steps than 
> > my present Rigol 4062 for 3458a AC calibration. I have two EL 1400 
> > 0.25V voltage thermal converters that I was trying to use in a test 
> > setup but they had such a low voltage range that I was forced to use 
> > my ATV-60 attenuator. It all kind of worked but a 0.1 db minimum step  
> > is a little course for easy use. The Rigol also suffers from this malady.
> > 
> > Charlie
> > 
> > On 8/31/2014 1:06 PM, Stephen Grady wrote:
> > > Charlie,
> > >
> > >
> > > The "Error Ur" is an under-range error; you have to apply an input above 10% of the range before it will display a reading. The 4920's are a very nice instrument. Their only problem is that they are all so old that they are reaching the stage where some components are drifting excessively or failing. I have come across 4920's that are drifting a little (more than there spec) between cals (and yes they need to be cal'd annually), another 4920 I came across had an intermittent failure in one of its power supplies.
> > >
> > > Kind Regards,
> > >
> > > Stephen Grady
> > > Sydney Australia
> > >
> > > -----Original Message-----
> > > From: volt-nuts [mailto:volt-nuts-bounces at febo.com] On Behalf Of 
> > > Charles Black
> > > Sent: Monday, 1 September 2014 3:19 AM
> > > To: ben at veritechmeasurements.com.au; Discussion of precise voltage 
> > > measurement
> > > Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on 
> > > ebay - 1 day left
> > >
> > > Hi Ben,
> > >
> > > I am going to check this out today to find if it might be helpfull around here for my AC calibration. It has an error message: "Error Ur"
> > > so some fixing is going to be needed. On the back it says it's got Option 80, whatever that is.
> > >
> > > Charlie
> > >
> > >
> > > On 8/31/2014 5:37 AM, ben wrote:
> > >> Hello all,
> > >> Just a heads up. I noted there is a lonely Datron / Wavetek 4920M 
> > >> AC voltmeter for sale on ebay, starting at US$650 (ending in 1 day 
> > >> !). I have little idea of its true working state or not (picture shows it powered on).
> > >> If fully working it would be a good buy for an AC voltmeter that 
> > >> is, I reckon, better than an HP 3458A. Only drawback with these 
> > >> models is the voltage input shell is always earthed, not floating. 
> > >> I have two of these 4920M's already, not really tempted by a third. 
> > >> I have a paper copies of operator, calibration, and service manual if anyone interested.
> > >>
> > >> regards,   ben.
> > >> _______________________________________________
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> > >
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