---------------------------------------- From: "ben" <ben@veritechmeasurements.com.au> Sent: Tuesday, September 02, 2014 11:25 PM To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 day left Hello all, I agree that the M version was made for military customers only, being a US Navy contract in about 1990. Aside from the thermal converter Wideband V input, key differences I am aware of between 4920 and 4920M are that the M version does not have mV ranges below 0.3V, and the M version has Filter options of only 100Hz and 10Hz (not additional 40Hz). Programming of Filter uses different syntax too. After a question from another member I have scanned my paper copy of the D 4920M Users manual, but its a bit of a mess. I will take it to work tomorrow and re-do it again properly, then upload it to KO4BB and BAMA. Hopefully the Calibration and Service manual will follow in short order. I can confirm that calibration of values 0.3V to 1000V use a thermal converter. As well, calibration of 100mV (0.3V range) will require a micropot and DC voltmeter. --- I have an alternative version of this email sitting in the Moderators in-tray which has attached a PDF of a paper presented at MSC 1990 conference (202kB file size). If returned to me I will find another site to post the paper - it makes good reading. If interested please email me and I can send it out individually. Otherwise, the whole MSC 1990 conference proceedings, including the Datron 4920M paper, can be found here -> msc-conf.com/wp-content/uploads/proceedings/MSC1990.pdf More to follow, regards, ben ---------------------------------------- From: "Stephen Grady" <grady.steve@gmail.com> Sent: Tuesday, September 02, 2014 7:54 PM To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> Subject: 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@febo.com] On Behalf Of acbern@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" > An: "Discussion of precise voltage measurement" > 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@febo.com] On Behalf Of > > Charles Black > > Sent: Monday, 1 September 2014 3:19 AM > > To: ben@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. > >> _______________________________________________ > >> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > >> and follow the instructions there. > >> > >> > >> > > > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > > > > --- > > This email is free from viruses and malware because avast! Antivirus protection is active. > > http://www.avast.com > > > > _______________________________________________ > > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > > and follow the instructions there. > > > > > > > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.

I uploaded the user manual for the 4920 model some time ago. Of note, the 4920 was offered with option 10. This added four additional millivolt ranges. I have this meter with the option 10. I think it may be a better alternative to the 4920m if you don't need the wideband option. Some of the 4920 had an external wideband input jack, but I have not seen this adapter for sale. It appears these were designed to compete with the Fluke 540B due to its AC/DC transfer feature. My meter has a limited calibration due to a couple ranges not meeting spec. Unfortunately, only the 4920M service manual is available. If anyone has the service manual for this, it would be appreciated. Todd Sent from my iPad > On Sep 2, 2014, at 10:17, "ben" <ben@veritechmeasurements.com.au> wrote: > > > > ---------------------------------------- > From: "ben" <ben@veritechmeasurements.com.au> > Sent: Tuesday, September 02, 2014 11:25 PM > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Subject: Re: [volt-nuts] Datron 4920M, AC Voltmeter, for sale on ebay - 1 > day left > > Hello all, > > I agree that the M version was made for military customers only, being a US > Navy contract in about 1990. Aside from the thermal converter Wideband V > input, key differences I am aware of between 4920 and 4920M are that the M > version does not have mV ranges below 0.3V, and the M version has Filter > options of only 100Hz and 10Hz (not additional 40Hz). Programming of Filter > uses different syntax too. > > After a question from another member I have scanned my paper copy of the D > 4920M Users manual, but its a bit of a mess. I will take it to work > tomorrow and re-do it again properly, then upload it to KO4BB and BAMA. > Hopefully the Calibration and Service manual will follow in short order. > > I can confirm that calibration of values 0.3V to 1000V use a thermal > converter. As well, calibration of 100mV (0.3V range) will require a > micropot and DC voltmeter. > > --- I have an alternative version of this email sitting in the Moderators > in-tray which has attached a PDF of a paper presented at MSC 1990 > conference (202kB file size). If returned to me I will find another site to > post the paper - it makes good reading. If interested please email me and > I can send it out individually. Otherwise, the whole MSC 1990 conference > proceedings, including the Datron 4920M paper, can be found here -> > msc-conf.com/wp-content/uploads/proceedings/MSC1990.pdf > > More to follow, > regards, > ben > > > > ---------------------------------------- > From: "Stephen Grady" <grady.steve@gmail.com> > Sent: Tuesday, September 02, 2014 7:54 PM > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Subject: 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@febo.com] On Behalf Of > acbern@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" >> An: "Discussion of precise voltage measurement" >> 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@febo.com] On Behalf Of >>> Charles Black >>> Sent: Monday, 1 September 2014 3:19 AM >>> To: ben@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. >>>> _______________________________________________ >>>> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to >>>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >>>> and follow the instructions there. >>> >>> _______________________________________________ >>> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >>> and follow the instructions there. >>> >>> >>> --- >>> This email is free from viruses and malware because avast! Antivirus > protection is active. >>> http://www.avast.com >>> >>> _______________________________________________ >>> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >>> and follow the instructions there. >> >> >> _______________________________________________ >> volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> and follow the instructions there. > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > > --- > This email is free from viruses and malware because avast! Antivirus > protection is active. > http://www.avast.com > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there. > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts > and follow the instructions there.