[time-nuts] Z3816a

[Bob Camp]

Hi

The 1938 and 10811 share the same basic crystal. The difference between a "very good" and a "acceptable" crystal can be an order of magnitude or more on ADEV at tau >= 1 second. In a very stable environment the rare 10811 with the 5x10^-13 at 1 second crystal will beat most of the production 10811's or 1938's. It's sort of luck of the draw in that respect. 

Bob

On Jun 5, 2010, at 11:31 PM, Robert Benward wrote:

> Joe,
> Thank you for your inputs!  The Z3815A I suspect is low voltage, it has a large PC card/motherboard type of connector with a large molex/amphenol power connector.  There appears to be a pair of DC-DC modules inside.  You would need to make some internal taps to get the 10MHz out to a BNC.  I also read somewhere an author's disappointment on the performance of the (his?) E1938A compare to the 10811.  I have one that is stand alone, running continuously.
> 
> I was under the impression that the maximum number of satellites in view is about 12 (24 active in a constellation hemisphere view), the other channels I think are used for WAAS and other data channels.
> 
> Bob
> 
> 
> 
> ----- Original Message ----- From: "J. L. Trantham" <jltran at att.net>
> To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
> Sent: Friday, June 04, 2010 10:56 PM
> Subject: Re: [time-nuts] Z3816a
> 
> 
>> Correction.  Z3805A tracks 16 satellites.
>> 
>> Joe
>> 
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of J. L. Trantham
>> Sent: Friday, June 04, 2010 9:51 PM
>> To: 'Discussion of precise time and frequency measurement'
>> Subject: Re: [time-nuts] Z3816a
>> 
>> I have Z3816A's and TBolt's.  Both do a great job.  For the TBolt, I use
>> TBoltMon.exe to monitor and for the Z3816A, I use SatStat.  The Z3816A
>> requires a 'null modem' adapter or an appropriately wired serial cable to
>> connect to the serial port of the computer where as the TBolt uses a
>> straight serial cable.
>> 
>> The only potential advantage of the Z3815A that I know of is the fact that
>> it uses the E1938A oscillator.  I have a couple of these oscillators and
>> they are superior in performance.  However, I have no firsthand knowledge of
>> performance of the Z3816A versus the Z3815A.
>> 
>> The Z3816A and the TBolt tracks up to 8 satellites.  The Z3816A also tells
>> you what other satellites are under consideration but are not being tracked,
>> perhaps up to 8 other non-used satellites.  I have at most seen the Z3816A
>> refer to a total of 11 satellites (8 tracked and 3 not tracked) but my
>> antenna is not in an ideal location.  I do not know about the Z3815A.  The
>> Z3805A tracks up to 12 satellites, if I recall correctly, and probably
>> should also be included in the comparison list if you are looking for a
>> GPSDO.
>> 
>> The Z3816A comes in at least two variants, one powered by a DC supply (I use
>> 30 VDC for mine) and the other powered by 120 VAC.  I don't know about the
>> Z3815A.
>> 
>> Good luck,
>> 
>> Joe
>> 
>> 
>> 
>> -----Original Message-----
>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>> Behalf Of Robert Benward
>> Sent: Friday, June 04, 2010 7:13 PM
>> To: time-nuts
>> Subject: [time-nuts] Z3816a
>> 
>> Hi All,
>> Is there any downside to a model Z3816A?  I also see a Z3815A on Ebay, but
>> the connector arrangement is not attractive.  Does anyone have a link to a
>> comparison chart between all these models?
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