[time-nuts] Spectracom 8170 Time of Day grief...(WWVB Clock)

J. L. Trantham jltran at att.net
Thu Jun 13 10:32:58 EDT 2013


In a slightly different direction, are there any commercially available 'PSK
Compliant Atomic Clocks' out there for those of us used to looking at the
'correct time'?

Also, what, exactly, was the advantage of changing modulation formats?  That
'killed' all the existing 'Atomic Clocks'?

I have looked at the Costas Loop article by Paul and it looks doable but I
probably could not make it look presentable to my wife sitting on a shelf.

Thanks.

Joe

-----Original Message----- 
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of paul swed
Sent: Thursday, June 13, 2013 7:34 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Spectracom 8170 Time of Day grief...

Burt search time nuts its all there. Its not a kit by any means.
Spectracom did a very good job. To good, though in reality they simply
reused the phase tracking rcvr from other units. Essentially the system
locks to the stable carrier creating a local replica and then removes the
carrier recovering just the AM. Or think of it as subtracting the carrier
leaving just the data. Very good design very bad for PSK, since the carrier
no longer has a relationship.
Nist and spectracom did put notices and such out for over a year, so what
can you say. Though we all have lots of strong opinions actually. Don't want
to start that thread again.
I have often thought and will spend no time doing it. Simply replace the
demod with a diode detector. Now its not actually quite that easy. But if
the only thing I had was a 8170 what the heck. The schematics of the system
are available at spectracom.

Near as I can tell the 8170 would run about 2 days on a fix.

Off to seriously sleazzy land. You could always bugger a gps clock into the
system adapting GPS time to local time by a micro. But that really is ugly.
Though you end up with those nice clock digits working again. Hey when you
do that send me the old rcvr parts. ;-)

Regards
Paul.


On Thu, Jun 13, 2013 at 12:37 AM, Burt I. Weiner <biwa at att.net> wrote:

> Paul,
>
> Ummmm... What a revolting development this is.  My 9150-52054 have a 
> smaller readout out that I can't see without climbing up on my bench, 
> so I suppose I will no longer know what time it is.
>
> I've never really had to delve into the 8170 so I wasn't up to speed 
> on how they derived the data from the carrier prior to the new PSK 
> format.  I was under the misunderstanding that it was strictly from 
> amplitude variation.  I guess it is, except for the manner in which 
> they determine the changes.
>
> Please tell me about the "d-psk-r" you mentioned.  Also do you know 
> the times of day WWVB reverts to the old method and for how long?  
> I'll have to go to their site and see.
>
> Burt, K6OQK
>
> At 04:46 PM 6/12/2013, time-nuts-request at febo.com wrote
>
>> Burt
>> One other tidbit the phase mod will exactly cause what you see.
>> Spectracom used phase tracking to demodulate the AM time signal. 
>> Thats why its nuts.
>>
>>
>> On Wed, Jun 12, 2013 at 5:49 PM, paul swed <paulswedb at gmail.com> wrote:
>>
>> > Burt
>> > There is nothing wrong with your 8170. WWVB no longer allows it to 
>> > work correctly because of the phase modulation. They went to all 
>> > psk about 1 month ago. They had been reverting back twice a day for 
>> > things like the 8170.
>> > So the ole 8170 is dead.
>> > You need to build something like the d-psk-r to get it going though 
>> > I
>> have
>> > not had time to actually add the am phase flipper precisely for the
>> likes
>> > of a 8170. I have one also.
>> > Sorry
>> > Paul
>> > WB8TSL
>> >>
>> > On Wed, Jun 12, 2013 at 5:35 PM, Burt I. Weiner <biwa at att.net> wrote:
>> >
>> >> My good old Spectracom 8170 is not setting time.  I don't use it 
>> >> for frequency, just as a clock for my Hazetorium.  I live about 20 
>> >> minutes north of downtown Los Angles in Glendale.  The antenna I'm 
>> >> using is the Ferrite Rod loop in PVC that came with the 8170.  
>> >> It's located on my
>> back
>> >> porch just laying on the floor with its maximum pickup direction
>> towards
>> >> Boulder, Colorado.  It has worked reliably for many years in that
>> location.
>> >>
>> >> The symptoms are...
>>
>
> Burt I. Weiner Associates
> Broadcast Technical Services
> Glendale, California  U.S.A.
> biwa at att.net
> www.biwa.cc
> K6OQK
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