[time-nuts] Solatrtron 7151 DMM

Sat Nov 28 18:02:30 UTC 2009

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:           	time-nuts-request at febo.com
Subject:        	time-nuts Digest, Vol 64, Issue 95
To:             	time-nuts at febo.com
Send reply to:  	time-nuts at febo.com
Date sent:      	Sat, 28 Nov 2009 15:42:05 +0000

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> 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
>       (SAIDJACK at aol.com)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sat, 28 Nov 2009 15:27:35 +0200
> From: Saku Ytti <saku at ytti.fi>
> Subject: [time-nuts] Time illiterate query about feasibility of
> 	determining	source clock quality based on NTP jitter/disp and offset
> To: time-nuts at febo.com
> Message-ID:
> 	<831084990911280527u317e8af7qbce051f07f78b340 at mail.gmail.com>
> 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" <stanw1le at verizon.net>
> Subject: [time-nuts] Santa's Visit #1
> To: time-nuts at febo.com
> Message-ID: <4B114394.5080609 at verizon.net>
> 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: SAIDJACK at aol.com
> Subject: Re: [time-nuts] Double oven ocxo's was Tbolt reception
> 	problems
> To: time-nuts at febo.com
> Message-ID: <ce3.5e1939e7.38429eb2 at aol.com>
> 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,  
> richard at karlquist.com 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
> 
> 
> 
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-- 
Jan Fredriksson
http://www.41hz.com