[time-nuts] Thunderbolt distribution amplifier needed

BD Systems Inc. bdsysco at yahoo.com
Tue Aug 21 23:58:12 EDT 2012


I currently use a Grass Valley Group 8802 video distribution amp (DA).  Yes they start to roll-off the frequency at 6 MHz but the roll-off is gradual and it will certianly pass 10 MHz with no problem.  Remember you are not passing multple frequencies or multi-burst, just 10 MHz.  Also, these DAs are designed be unity gain and to handle approximately 1 volt p-p so be carefull of clipping if you drive much more than that level or alternatively, pad down the input to a 1 volt level.


From: "time-nuts-request at febo.com" <time-nuts-request at febo.com>
To: time-nuts at febo.com 
Sent: Tuesday, August 21, 2012 1:00 PM
Subject: time-nuts Digest, Vol 97, Issue 63

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Today's Topics:

  1. Re: Thunderbolt distribution amplifier needed (Chris Albertson)
  2. Re: Thunderbolt distribution amplifier needed (Pete Lancashire)
  3. Re: Thunderbolt distribution amplifier needed (paul swed)
  4. Re: : L1 GPS timing signal(s) into local time    oncomputer(s)
      (Bill Hawkins)
  5. Maker Faire Sept 29 & 30 NY Hall of Science (MITCHELL JANOFF)
  6. Re: : L1 GPS timing signal(s) into local time on computer(s)
      (Hal Murray)


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

Message: 1
Date: Tue, 21 Aug 2012 09:54:14 -0700
From: Chris Albertson <albertson.chris at gmail.com>
To: "BD Systems Inc." <bdsysco at yahoo.com>,     Discussion of precise time
    and frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Thunderbolt distribution amplifier needed
Message-ID:
    <CABbxVHtkvH5wixXzOEyo2-nv51Ev2vnrsbapAOj851-pydAxMw at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

I bought a eBay video distribution amp.  The bandwidth was not as good as
I liked but for some reason the opamps were run off +/- 12 volts.  Raising
the power to +/- 18V greatly improved the performance of the amp.  Many
video amp assume the signal to 6MHz bandwidth might not be ideal.  But on
the other hand some old studio equipment is grossly over engineered and
might be very good for 10Mhz distribution.  The good news is the today
analog video amps are cheap as dirt as no one wants analog video.




On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. <bdsysco at yahoo.com> wrote:

> Use an analog video distribution amplifier (Grass Valley Group, Leitch,
> Ross Video etc).  These have between 6 to 8 outputs and will provide a
> reference to various test equipment.
>
>
> From: "time-nuts-request at febo.com" <time-nuts-request at febo.com>
> To: time-nuts at febo.com
> Sent: Tuesday, August 21, 2012 6:00 AM
> Subject: time-nuts Digest, Vol 97, Issue 60
>
> Send time-nuts mailing list submissions to
>    time-nuts at febo.com
>
> 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
>    time-nuts-request at febo.com
>
> You can reach the person managing the list at
>    time-nuts-owner at febo.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of time-nuts digest..."
>
>
> Today's Topics:
>
>  1. Thunderbolt distribution amplifier needed. (Chris Wilson)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 21 Aug 2012 11:44:17 +0100
> From: Chris Wilson <chris at chriswilson.tv>
> To: "time-nuts at febo.com" <time-nuts at febo.com>
> Subject: [time-nuts] Thunderbolt distribution amplifier needed.
> Message-ID: <5746920.20120821114417 at chriswilson.tv>
> Content-Type: text/plain; charset=windows-1252
>
>
>
>  21/08/2012 11:40
>
> Can anyone please link specifically to a suitable distribution amp for
> my TB please, either here if it's allowed, or by e-mail to me at
> chris at chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay
> purchase would be painless. I feel it would be really easy for someone
> as daft as me to buy something totally unsuitable. I want to run David
> Partridge's divider board and have enough 10MHz signalleft to run other
> stuff as well, David recommended I run the amp between the TB and his
> divider. Cheers.
>
> --
>      Best Regards,
>                  Chris Wilson.
> mailto: chris at chriswilson.tv
>
>
>
>
> ------------------------------
>
> _______________________________________________
> time-nuts mailing list
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> *****************************************
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>



-- 

Chris Albertson
Redondo Beach, California


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

Message: 2
Date: Tue, 21 Aug 2012 10:12:27 -0700
From: Pete Lancashire <pete at petelancashire.com>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Cc: "BD Systems Inc." <bdsysco at yahoo.com>
Subject: Re: [time-nuts] Thunderbolt distribution amplifier needed
Message-ID:
    <CAA-F0u9nkye77oSz_9CDOgCtRKfYkSA6iqJyVFG2FLJzavCNSw at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

It all depends on the brand and if 'commercial' or not. A Grass Valley
(dont remember the model)
tested is 3db down starting around 25 MHz. I have also seen others
that have a LP filter option
installed on the input module.

-pete




On Tue, Aug 21, 2012 at 9:54 AM, Chris Albertson
<albertson.chris at gmail.com> wrote:
> I bought a eBay video distribution amp.  The bandwidth was not as good as
> I liked but for some reason the opamps were run off +/- 12 volts.  Raising
> the power to +/- 18V greatly improved the performance of the amp.  Many
> video amp assume the signal to 6MHz bandwidth might not be ideal.  But on
> the other hand some old studio equipment is grossly over engineered and
> might be very good for 10Mhz distribution.  The good news is the today
> analog video amps are cheap as dirt as no one wants analog video.
>
>
>
>
> On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. <bdsysco at yahoo.com> wrote:
>
>> Use an analog video distribution amplifier (Grass Valley Group, Leitch,
>> Ross Video etc).  These have between 6 to 8 outputs and will provide a
>> reference to various test equipment.
>>
>>
>> From: "time-nuts-request at febo.com" <time-nuts-request at febo.com>
>> To: time-nuts at febo.com
>> Sent: Tuesday, August 21, 2012 6:00 AM
>> Subject: time-nuts Digest, Vol 97, Issue 60
>>
>> Send time-nuts mailing list submissions to
>>    time-nuts at febo.com
>>
>> 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
>>    time-nuts-request at febo.com
>>
>> You can reach the person managing the list at
>>    time-nuts-owner at febo.com
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of time-nuts digest..."
>>
>>
>> Today's Topics:
>>
>>  1. Thunderbolt distribution amplifier needed. (Chris Wilson)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 21 Aug 2012 11:44:17 +0100
>> From: Chris Wilson <chris at chriswilson.tv>
>> To: "time-nuts at febo.com" <time-nuts at febo.com>
>> Subject: [time-nuts] Thunderbolt distribution amplifier needed.
>> Message-ID: <5746920.20120821114417 at chriswilson.tv>
>> Content-Type: text/plain; charset=windows-1252
>>
>>
>>
>>  21/08/2012 11:40
>>
>> Can anyone please link specifically to a suitable distribution amp for
>> my TB please, either here if it's allowed, or by e-mail to me at
>> chris at chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay
>> purchase would be painless. I feel it would be really easy for someone
>> as daft as me to buy something totally unsuitable. I want to run David
>> Partridge's divider board and have enough 10MHz signalleft to run other
>> stuff as well, David recommended I run the amp between the TB and his
>> divider. Cheers.
>>
>> --
>>      Best Regards,
>>                  Chris Wilson.
>> mailto: chris at chriswilson.tv
>>
>>
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> time-nuts mailing list
>> time-nuts at febo.com
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>
>> End of time-nuts Digest, Vol 97, Issue 60
>> *****************************************
>> _______________________________________________
>> 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.
>>
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
> _______________________________________________
> 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: Tue, 21 Aug 2012 13:20:05 -0400
From: paul swed <paulswedb at gmail.com>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Subject: Re: [time-nuts] Thunderbolt distribution amplifier needed
Message-ID:
    <CAD2JfAjbi0bPxzO6f+=CqvhsJtvNJbid2_bXjWi1U4X2R=rcdQ at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1

Exactly right on many of the accounts. The oldest DAs may be 6 Mhz but I am
not sure you will even find them any longer. The more modern preHDTVs were
all easily in the 10-30 Mhz region. Most have eq adjustments so that you
could peak for the higher frequency like 10 Mhz.
Boy the amps and chassis are cheap these days. Stay clear of more
complicated DAs like delay if possible. Just lots of stuff to add noise and
lots of little jumpers to change.
Picked up 2 trays of GVG 8500 class DAs for $30 each. They are junk
actually these days. So most are headed to the dumpsters.
Regards
Paul

On Tue, Aug 21, 2012 at 12:54 PM, Chris Albertson <albertson.chris at gmail.com
> wrote:

> I bought a eBay video distribution amp.  The bandwidth was not as good as
> I liked but for some reason the opamps were run off +/- 12 volts.  Raising
> the power to +/- 18V greatly improved the performance of the amp.  Many
> video amp assume the signal to 6MHz bandwidth might not be ideal.  But on
> the other hand some old studio equipment is grossly over engineered and
> might be very good for 10Mhz distribution.  The good news is the today
> analog video amps are cheap as dirt as no one wants analog video.
>
>
>
>
> On Tue, Aug 21, 2012 at 7:17 AM, BD Systems Inc. <bdsysco at yahoo.com>
> wrote:
>
> > Use an analog video distribution amplifier (Grass Valley Group, Leitch,
> > Ross Video etc).  These have between 6 to 8 outputs and will provide a
> > reference to various test equipment.
> >
> >
> > From: "time-nuts-request at febo.com" <time-nuts-request at febo.com>
> > To: time-nuts at febo.com
> > Sent: Tuesday, August 21, 2012 6:00 AM
> > Subject: time-nuts Digest, Vol 97, Issue 60
> >
> > Send time-nuts mailing list submissions to
> >    time-nuts at febo.com
> >
> > 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
> >    time-nuts-request at febo.com
> >
> > You can reach the person managing the list at
> >    time-nuts-owner at febo.com
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of time-nuts digest..."
> >
> >
> > Today's Topics:
> >
> >  1. Thunderbolt distribution amplifier needed. (Chris Wilson)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Tue, 21 Aug 2012 11:44:17 +0100
> > From: Chris Wilson <chris at chriswilson.tv>
> > To: "time-nuts at febo.com" <time-nuts at febo.com>
> > Subject: [time-nuts] Thunderbolt distribution amplifier needed.
> > Message-ID: <5746920.20120821114417 at chriswilson.tv>
> > Content-Type: text/plain; charset=windows-1252
> >
> >
> >
> >  21/08/2012 11:40
> >
> > Can anyone please link specifically to a suitable distribution amp for
> > my TB please, either here if it's allowed, or by e-mail to me at
> > chris at chriswilson.tv ? Cost is a factor, and I am in the UK. An Ebay
> > purchase would be painless. I feel it would be really easy for someone
> > as daft as me to buy something totally unsuitable. I want to run David
> > Partridge's divider board and have enough 10MHz signalleft to run other
> > stuff as well, David recommended I run the amp between the TB and his
> > divider. Cheers.
> >
> > --
> >      Best Regards,
> >                  Chris Wilson.
> > mailto: chris at chriswilson.tv
> >
> >
> >
> >
> > ------------------------------
> >
> > _______________________________________________
> > time-nuts mailing list
> > time-nuts at febo.com
> > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> >
> > End of time-nuts Digest, Vol 97, Issue 60
> > *****************************************
> > _______________________________________________
> > 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.
> >
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
> _______________________________________________
> 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: Tue, 21 Aug 2012 13:10:34 -0500
From: "Bill Hawkins" <bill at iaxs.net>
To: "'Discussion of precise time and frequency measurement'"
    <time-nuts at febo.com>
Subject: Re: [time-nuts] : L1 GPS timing signal(s) into local time
    oncomputer(s)
Message-ID: <AD2ABF12D68C4AFBA3309199259D50DE at cyrus>
Content-Type: text/plain;    charset="us-ascii"

The importance of cable delay depends on what you are doing with the time.
If you are taking data in remote locations with different GPS receivers,
then cable delay is necessary to correlate the results in time. See the
recent mail on FTL neutrinos.

If you are being NTP Stratum 0 to one network (please don't assert NTP
Stratum 0 to the Internet with a rig put together from eBay parts), then
the cable delay is a miniscule phase shift between you and reality.

Bill Hawkins


-----Original Message-----
From: Sarah White
Sent: Tuesday, August 21, 2012 11:53 AM

Wow. Okay. The user manual actual considers this cable delay to be worth
mention?

I can see why the trimble thunderbolt is a favorite among time nuts <3

I'm sold.





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

Message: 5
Date: Tue, 21 Aug 2012 11:27:35 -0700 (PDT)
From: MITCHELL JANOFF <majanoff at verizon.net>
To: "time-nuts at febo.com" <time-nuts at febo.com>
Subject: [time-nuts] Maker Faire Sept 29 & 30 NY Hall of Science
Message-ID:
    <1345573655.14099.YahooMailNeo at web84508.mail.ne1.yahoo.com>
Content-Type: text/plain; charset=iso-8859-1

I'm working on a "Time-Nuts" based exhibit at the 2012 MakerFaire in NYC (http://makerfaire.com/newyork/2012/). The idea is the history of time distribution with a focus on modern timekeeping (1900 to the present). It is a non-commercial booth, focused on education, and?demonstrating micro-processing technology and timekeeping. I plan to bring a couple of atomic clocks, various WWV and WWVB receivers,?an oscilloscope and GPS devices?that I've connected to microprocessors to display the time and also synchronize clocks from the Self Winding Clock Company of NY. My application has been accepted and I'm now working on the actual exhibit. If there is anyone in the NYC area that would like to collaborate on this project, please contact me via email. Any suggestions for the exhibit are appreciated.?
?
Thanks.?

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

Message: 6
Date: Tue, 21 Aug 2012 12:00:00 -0700
From: Hal Murray <hmurray at megapathdsl.net>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Subject: Re: [time-nuts] : L1 GPS timing signal(s) into local time on
    computer(s)
Message-ID:
    <20120821190000.96D0C800037 at ip-64-139-1-69.sjc.megapath.net>
Content-Type: text/plain; charset=us-ascii


kuzetsa at gmail.com said:
> ... I would presume that the fixed location used for above calculations
> would be relative to the position of the antenna?

A side effect of figuring out where you are is figuring out when you are 
there.

There are 4 unknowns: X, Y, Z, T, so you need 4 equations.  You get one 
equation from each satellite so you need 4 satellites.  If you assume you are 
on the surface of the earth, you can get away with only 3 satellites.

Yes, that tells you where the antenna is located.

If you know where you are, you only need 1 satellite to get the time.


> I read somewhere that even compensating for the length of the
> antenna cabling is important?

> Wow. Okay. The user manual actual considers this cable delay to be worth
> mention? 

Sure.  The speed of light in air/vacuum is 1 ft/ns.  Coax (and fiber) is 
slower.  Junk coax is roughly half as fast.  Good coax (foam) is roughly 
2/3rds as fast.  So it's easy to get 100 ns but unlikely to get more than a 
microsecond on an amateur budget.

Whether that is important for you depends upon your application and the 
length of the antenna cable.  With a modern not super-expensive scope, it's 
easy to see 1 ns offsets, so cable lengths could be important on something as 
simple as comparing the PPS outputs from 2 GPS systems.


Don't forget to consider the lengths of other cables in your setup.

I remember getting an interesting lesson in this area many years ago.  We had 
a couple of scope probes with long cables.  I was using one long one and one 
normal one and looking at high speed digital signals.  The offset was enough 
to confuse me.


-- 
These are my opinions.  I hate spam.






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

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