[time-nuts] Z3805 hold-Over

Doug Parker doug.parker at btinternet.com
Mon Nov 12 04:13:14 EST 2012


Hi Chuck,
 
Thank you for the explanation of the SS and C/N modes used in the Z3805A, I hadn't noticed the change in designation on the receiver status.
This totally explains the difference in signal reports between my Z3801 & Z3805. Sometimes you can't see the wood for the trees.
 
With this in mind, it looks like my Z3805 GPS is receiving an acceptable signal with a typical CF of 40+, so back to the drawing board. Or better still, just leave the Z3805A  alone for a month or so and let everything settle and then if neccesary, investigate further.
 
thanks
Doug

 

________________________________
 From: BD Systems Inc. <bdsysco at yahoo.com>
To: "time-nuts at febo.com" <time-nuts at febo.com> 
Sent: Sunday, 11 November 2012, 22:58
Subject: [time-nuts] Z3805 hold-Over
  
The Z3805A utilizes Carrier to Noise C/N instead of Signal Strength.  Typical values of C/N are 25 - 55 whereas Signal Strength can range from ~30 - 255.

Chuck Zabilski
BD Systems, Inc.


________________________________
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To: time-nuts at febo.com 
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Today's Topics:

   1. Re: Z3805 hold-Over (jmfranke)
   2. Re: Z3805 hold-Over (Doug Parker)
   3. Re: Z3805 hold-Over (Volker Esper)
   4. Re: Z3805 hold-Over (Volker Esper)
   5. Re: Z3805 hold-Over (Bob Camp)
   6. Re: Z3805 hold-Over (Bob Camp)


----------------------------------------------------------------------

Message: 1
Date: Sun, 11 Nov 2012 14:04:15 -0500
From: "jmfranke" <jmfranke at cox.net>
To: "Doug Parker" <doug.parker at btinternet.com>,    <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID: <DC6BAEDBFD0747039B478B94F2E3A837 at Franke>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
    reply-type=original

Your 21 ns for 1PPS and T1 does not look too bad, but the satellite received 
signal strengths are too low. You should have at least four or five SS 
values above 60-80. I always have at least three SS readings above 100. My 
Holdover runs between 03 and 4 microseconds.

John  WA4WDL

--------------------------------------------------
From: "Doug Parker" <doug.parker at btinternet.com>
Sent: Sunday, November 11, 2012 1:36 PM
To: <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over

>
>
>
> Hi,
>
> I've got a Z3805 from one of the Chineese sources and had problems with 
> the HP 11801 oscillator which came with it. Even after a couple of weeks 
> operartion it was moving vast EFC voltages with the 'Holdover Uncertainty 
> Predict' reaching a lowest of 19uS.
>
> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC 
> change is back to a resonable level, but after 5 days of settling down, 
> the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is 
> holding about that value.
>
> Could some one please advise what figures they are getting. As there's 
> something sticking in my mind that the whole system should be lower than 
> 6.3uS after 3 days of locked operation. Or have I been dreaming.....
>
> I have attached a JPG of my GPSCon graph, hope it helps
>
> thanks & 73s
> Doug
> G4DZU
> http://www.g4dzu.com/



> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 





------------------------------

Message: 2
Date: Sun, 11 Nov 2012 19:24:20 +0000 (GMT)
From: Doug Parker <doug.parker at btinternet.com>
To: jmfranke <jmfranke at cox.net>, "time-nuts at febo.com"
    <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID:
    <1352661860.17054.YahooMailNeo at web87704.mail.ir2.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

Hi John,
?
Thanks for the observation, with the same antenna plugged into my Z3801, I get an SS of at least 90.
?
I'll place a preamp in line to see if that increases the SS on the 3805 , maybe my problem is the GPS RX isn't well. Great point.
?
Of course, ?I'll watch out for the 5V power feed going up the coax for the preamp in the antenna.
?
73s
Doug
G4DZU


________________________________
From: jmfranke <jmfranke at cox.net>
To: Doug Parker <doug.parker at btinternet.com>; time-nuts at febo.com 
Sent: Sunday, 11 November 2012, 19:04
Subject: Re: [time-nuts] Z3805 hold-Over
  
Your 21 ns for 1PPS and T1 does not look too bad, but the satellite received signal strengths are too low. You should have at least four or five SS values above 60-80. I always have at least three SS readings above 100. My Holdover runs between 03 and 4 microseconds.

John? WA4WDL

--------------------------------------------------
From: "Doug Parker" <doug.parker at btinternet.com>
Sent: Sunday, November 11, 2012 1:36 PM
To: <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over

> 
> 
> 
> Hi,
> 
> I've got a Z3805 from one of the Chineese sources and had problems with the HP 11801 oscillator which came with it. Even after a couple of weeks operartion it was moving vast EFC voltages with the 'Holdover Uncertainty Predict' reaching a lowest of 19uS.
> 
> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC change is back to a resonable level, but after 5 days of settling down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is holding about that value.
> 
> Could some one please advise what figures they are getting. As there's something sticking in my mind that the whole system should be lower than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
> 
> I have attached a JPG of my GPSCon graph, hope it helps
> 
> thanks & 73s
> Doug
> G4DZU
> http://www.g4dzu.com/



> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 

------------------------------

Message: 3
Date: Sun, 11 Nov 2012 20:29:11 +0100
From: Volker Esper <ailer2 at t-online.de>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID: <509FFC87.3090609 at t-online.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed


Yes, I guess, signal strength is essential. My holdover uncertainty is 
(after 1 weeks) about 1 to 2us.

Volker DF9PL

Am 11.11.2012 20:04, schrieb jmfranke:
> Your 21 ns for 1PPS and T1 does not look too bad, but the satellite
> received signal strengths are too low. You should have at least four or
> five SS values above 60-80. I always have at least three SS readings
> above 100. My Holdover runs between 03 and 4 microseconds.
>
> John WA4WDL
>
> --------------------------------------------------
> From: "Doug Parker" <doug.parker at btinternet.com>
> Sent: Sunday, November 11, 2012 1:36 PM
> To: <time-nuts at febo.com>
> Subject: Re: [time-nuts] Z3805 hold-Over
>
>>
>>
>>
>> Hi,
>>
>> I've got a Z3805 from one of the Chineese sources and had problems
>> with the HP 11801 oscillator which came with it. Even after a couple
>> of weeks operartion it was moving vast EFC voltages with the 'Holdover
>> Uncertainty Predict' reaching a lowest of 19uS.
>>
>> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily
>> EFC change is back to a resonable level, but after 5 days of settling
>> down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and
>> is holding about that value.
>>
>> Could some one please advise what figures they are getting. As there's
>> something sticking in my mind that the whole system should be lower
>> than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
>>
>> I have attached a JPG of my GPSCon graph, hope it helps
>>
>> thanks & 73s
>> Doug
>> G4DZU
>> http://www.g4dzu.com/
>
>
>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>





------------------------------

Message: 4
Date: Sun, 11 Nov 2012 20:33:56 +0100
From: Volker Esper <ailer2 at t-online.de>
To: Doug Parker <doug.parker at btinternet.com>,     Discussion of precise
    time and frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID: <509FFDA4.9050902 at t-online.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed


You can easily check the 5V by measuring at the open antenna plug. When 
plugging the antenna, total current consumption should increase by about 
10mA or so.


Am 11.11.2012 20:24, schrieb Doug Parker:
> Hi John,
>
> Thanks for the observation, with the same antenna plugged into my Z3801, I get an SS of at least 90.
>
> I'll place a preamp in line to see if that increases the SS on the 3805 , maybe my problem is the GPS RX isn't well. Great point.
>
> Of course,  I'll watch out for the 5V power feed going up the coax for the preamp in the antenna.
>
> 73s
> Doug
> G4DZU
>
>
> ________________________________
>   From: jmfranke<jmfranke at cox.net>
> To: Doug Parker<doug.parker at btinternet.com>; time-nuts at febo.com
> Sent: Sunday, 11 November 2012, 19:04
> Subject: Re: [time-nuts] Z3805 hold-Over
>
> Your 21 ns for 1PPS and T1 does not look too bad, but the satellite received signal strengths are too low. You should have at least four or five SS values above 60-80. I always have at least three SS readings above 100. My Holdover runs between 03 and 4 microseconds.
>
> John  WA4WDL
>
> --------------------------------------------------
> From: "Doug Parker"<doug.parker at btinternet.com>
> Sent: Sunday, November 11, 2012 1:36 PM
> To:<time-nuts at febo.com>
> Subject: Re: [time-nuts] Z3805 hold-Over
>
>>
>>
>>
>> Hi,
>>
>> I've got a Z3805 from one of the Chineese sources and had problems with the HP 11801 oscillator which came with it. Even after a couple of weeks operartion it was moving vast EFC voltages with the 'Holdover Uncertainty Predict' reaching a lowest of 19uS.
>>
>> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC change is back to a resonable level, but after 5 days of settling down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is holding about that value.
>>
>> Could some one please advise what figures they are getting. As there's something sticking in my mind that the whole system should be lower than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
>>
>> I have attached a JPG of my GPSCon graph, hope it helps
>>
>> thanks&  73s
>> Doug
>> G4DZU
>> http://www.g4dzu.com/
>
>
>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>





------------------------------

Message: 5
Date: Sun, 11 Nov 2012 15:46:27 -0500
From: Bob Camp <lists at rtty.us>
To: Doug Parker <doug.parker at btinternet.com>,    Discussion of precise
    time and frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID: <9EC6326B-C8DF-4ED3-A1D0-3CBF4E7D31D7 at rtty.us>
Content-Type: text/plain; charset=iso-8859-1

Hi

Most of mine get down to ridiculously low numbers after a few weeks to a few months on. How long seems to depend on how many years the unit has been off power. Any estimate under 500 ns is questionable with that hardware. The firmware seems to be quite happy reporting numbers well below that. 

Bob

On Nov 11, 2012, at 1:36 PM, Doug Parker <doug.parker at btinternet.com> wrote:

> 
>  
> 
> Hi,
> 
> I've got a Z3805 from one of the Chineese sources and had problems with the HP 11801 oscillator which came with it. Even after a couple of weeks  operartion it was moving vast EFC voltages with  the 'Holdover Uncertainty Predict'  reaching a lowest of 19uS.
> 
> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC change is back to a resonable level, but after 5 days of settling down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is holding about that value.
> 
> Could some one please advise what figures they are getting. As there's something sticking in my mind that the whole system should be lower than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
> 
> I have attached a JPG of my GPSCon graph, hope it helps
> 
> thanks & 73s
> Doug
> G4DZU
> http://www.g4dzu.com/<3801-5Days.jpg>_______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




------------------------------

Message: 6
Date: Sun, 11 Nov 2012 15:52:44 -0500
From: Bob Camp <lists at rtty.us>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Subject: Re: [time-nuts] Z3805 hold-Over
Message-ID: <C9C84563-7B7B-4EEB-BE78-41098B17802C at rtty.us>
Content-Type: text/plain; charset=iso-8859-1

Hi

You may well over drive the GPS board if you put more amplification in the line. If the antenna and coax work ok with a 3801, they should be fine with a 3805. If you have a very high gain setup, it may be ok for the 3801 and be over driving the 3805 already.

What kind of antenna and coax are you using?

Bob

On Nov 11, 2012, at 2:24 PM, Doug Parker <doug.parker at btinternet.com> wrote:

> Hi John,
>  
> Thanks for the observation, with the same antenna plugged into my Z3801, I get an SS of at least 90.
>  
> I'll place a preamp in line to see if that increases the SS on the 3805 , maybe my problem is the GPS RX isn't well. Great point.
>  
> Of course,  I'll watch out for the 5V power feed going up the coax for the preamp in the antenna.
>  
> 73s
> Doug
> G4DZU
> 
> 
> ________________________________
> From: jmfranke <jmfranke at cox.net>
> To: Doug Parker <doug.parker at btinternet.com>; time-nuts at febo.com 
> Sent: Sunday, 11 November 2012, 19:04
> Subject: Re: [time-nuts] Z3805 hold-Over
> 
> Your 21 ns for 1PPS and T1 does not look too bad, but the satellite received signal strengths are too low. You should have at least four or five SS values above 60-80. I always have at least three SS readings above 100. My Holdover runs between 03 and 4 microseconds.
> 
> John  WA4WDL
> 
> --------------------------------------------------
> From: "Doug Parker" <doug.parker at btinternet.com>
> Sent: Sunday, November 11, 2012 1:36 PM
> To: <time-nuts at febo.com>
> Subject: Re: [time-nuts] Z3805 hold-Over
> 
>> 
>> 
>> 
>> Hi,
>> 
>> I've got a Z3805 from one of the Chineese sources and had problems with the HP 11801 oscillator which came with it. Even after a couple of weeks operartion it was moving vast EFC voltages with the 'Holdover Uncertainty Predict' reaching a lowest of 19uS.
>> 
>> So I tried the HP oscillator from my Z3801 in the Z3805 and the daily EFC change is back to a resonable level, but after 5 days of settling down, the 'Holdeover Uncertainy Predict' has only got down to 10uS.and is holding about that value.
>> 
>> Could some one please advise what figures they are getting. As there's something sticking in my mind that the whole system should be lower than 6.3uS after 3 days of locked operation. Or have I been dreaming.....
>> 
>> I have attached a JPG of my GPSCon graph, hope it helps
>> 
>> thanks & 73s
>> Doug
>> G4DZU
>> http://www.g4dzu.com/
> 
> 
> 
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there. 
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.




------------------------------

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