Some time ago someone posted about these DMMs and power filter problems. I had similar problems with one.
It was caused by a short by components touching the grounding / shielding in the inside of the top lid which is earth grounded. The upper PCB was a bit out of position. I de-powerd it quite quickly so it was not badly damaged, but the smell from the input filer was so bad I had to get rid of the DMM! Luckily I have another 7151 :-) I have a VB6 app fore it for simple datalogging if someone is interested, I can send it. Jan From: [email protected] Subject: time-nuts Digest, Vol 64, Issue 95 To: [email protected] Send reply to: [email protected] Date sent: Sat, 28 Nov 2009 15:42:05 +0000 > Send time-nuts mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of time-nuts digest..." > > > Today's Topics: > > 1. Time illiterate query about feasibility of determining source > clock quality based on NTP jitter/disp and offset (Saku Ytti) > 2. Santa's Visit #1 (Stan, W1LE) > 3. Re: Double oven ocxo's was Tbolt reception problems > ([email protected]) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 28 Nov 2009 15:27:35 +0200 > From: Saku Ytti <[email protected]> > Subject: [time-nuts] Time illiterate query about feasibility of > determining source clock quality based on NTP jitter/disp and offset > To: [email protected] > Message-ID: > <[email protected]> > Content-Type: text/plain; charset=UTF-8 > > cisco#show ntp associations > > address ref clock st when poll reach > delay offset disp > *~meinberg-dhq .PPS. 1 13 256 377 2.6 > 1.53 3.7 > +~meinberg-lq .PPS. 1 131 256 377 2.1 > 1.83 1.4 > +~randomPC1 .GPS. 1 29 256 377 17.0 > 1.35 0.3 > +~randomPC2 randomPC3 2 45 256 377 17.6 1.17 0.3 > +~randomPC3 .GPS. 1 41 256 377 17.0 > 1.52 0.4 > * master (synced), # master (unsynced), + selected, - candidate, ~ configured > > > I see similar result all around, meinbergs which are lot closer, have > poorer offset > and disp. > Are there any conclusions I can draw from this? > > Funny thing is that cisco iscloser to randomPC2 than its source random PC3, > so I think just based on that, I can determine I can't use these values to > determine quality of source clock? > > But what would then explain how disp/jitter and offset are consistently better > towards the randomPC's which are considerably further down the network? > > With basically no clue about time, I have two uneducated guesses. > > 1) meinberg is embedded hardware, software processing is slow in it > compared to randomPC which runs software much faster, which is > much more visible in NTP than actual clock quality > > or > > 2) cisco and randomPC have similar clock hardware, something bulk > most hardware use, these clocks skew to same direction at relatively > similar rate, making the cisco and randomPC's having time quite close > to each other, both being bit further away from better clock. > > Thanks, > -- > ++ytti > > > > ------------------------------ > > Message: 2 > Date: Sat, 28 Nov 2009 10:36:52 -0500 > From: "Stan, W1LE" <[email protected]> > Subject: [time-nuts] Santa's Visit #1 > To: [email protected] > Message-ID: <[email protected]> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed > > Hello The Net: > > Execess to my needs is a older National Instruments > GPIB adapter card with what looks to be a 8 bit ISA interface to your PC. > > On the PCB is assy180340-01 rev a, not obvious to me what the NI model > number is. > I suspect drivers are still available from NI. > > First response direct to me (off of this reflector) can have it for my > cost of packing and mailing. > Paypal would be convenient for me. Local pickup within 1 week is OK. > > I have not had a PC with a ISA expansion interface in a few computer > generations, > so I can not use it, as I try to put some of my HP equipment on a network. > > Any interest, please advise. > > Santa, W1LE Cape Cod FN41sr > > > > > ZZZZz > > > > ------------------------------ > > Message: 3 > Date: Sat, 28 Nov 2009 10:41:38 EST > From: [email protected] > Subject: Re: [time-nuts] Double oven ocxo's was Tbolt reception > problems > To: [email protected] > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > Hi guys, > > it turns out I achieve the best results with an E1938A driven by a Fury > board, compared to my PRS-10 Rb. I have not tried a Fury GPSDO with a > standard DOCXO yet, but suspect similar results - that test to follow next > week. > > The standard deviation over 15 hours is about 2.3ns, the range less than > +/-8ns. Please see the attached plot. The E1938A has only been turned on > less than 2 days after a very long power-off period (4+ months), but it is > already very stable. > > Next step is to see which of the two is better, after that how much STS > improvement can be gained by removing the GPS disciplining. > > bye, > Said > > > In a message dated 11/25/2009 17:20:40 Pacific Standard Time, > [email protected] writes: > > We demonstrated thermal gains of over 1 million in the E1938A > single oven oscillator. You don't need a double oven. > > Rick Karlquist N6RK > > > > -------------- next part -------------- > A non-text attachment was scrubbed... > Name: E1938A_PRS10.gif > Type: image/gif > Size: 22684 bytes > Desc: not available > URL: > <http://www.febo.com/pipermail/time-nuts/attachments/20091128/118c72fa/attachment.gif> > > ------------------------------ > > _______________________________________________ > time-nuts mailing list > [email protected] > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > End of time-nuts Digest, Vol 64, Issue 95 > ***************************************** > -- Jan Fredriksson http://www.41hz.com _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
