[time-nuts] WWVB Antenna revisited/Spectracom 8182

Bob kb8tq kb8tq at n1k.org
Thu Mar 22 15:13:02 UTC 2018


Hi

You should DC block the output of the 8182 if you are going to run it straight 
to an antenna. 

The bigger issue is that WWVB changed their transmit format a couple years
ago. The signal they now send is not compatible with a lot of gear out there. 
It turns out that the 8182 is included on that list:

https://spectracom.com/support/retired-products/netclock?field_product_availability_ref_tid=94 <https://spectracom.com/support/retired-products/netclock?field_product_availability_ref_tid=94>

There are gizmos you can build to convert the new transmit format to the old 
one, I’m not sure if you are interested in going to that extreme. 

Bob


> On Mar 22, 2018, at 6:25 AM, D. Resor <organlists at pacbell.net> wrote:
> 
> I've been reading and researching what I will need to connect a Spectracom
> 8182 Netclock/2 for use here at home as a WWV(B) clock.
> 
> 
> 
> I found a post response from Feb 23, 2005 by Brian Kirby which includes the
> a link for a preamplifier schematic here:
> 
> 
> 
> 
> <http://www.febo.com/pipermail/time-nuts/attachments/20050223/94b9bd2c/attac
> hment-0008.pdf>
> http://www.febo.com/pipermail/time-nuts/attachments/20050223/94b9bd2c/attach
> ment-0008.pdf 
> 
> 
> 
> According to all information I have been able to gather, in California I
> really don't a preamplifier.   However the Spectracom 8182 manual discusses
> the use of a preamplifier (8207) with their antenna as "part of the system".
> 
> 
> 
> 
> My train of thought is, the 8182 superimposes 10.7vdc on the antenna BNC for
> powering the inline preamplifier.  If I do not use the preamplifier will
> this DC voltage create problems and attenuate the RF signal? Will the
> comparator circuit in the 8182 show the antenna to be open and therefore not
> operate correctly?  Would a decoupling network to prevent the DC voltage
> from reaching the antenna create the same problem?
> 
> 
> 
> Lastly I see in the preamplifier schematic DC power is used to power the
> transistors (+9 input) and how 60Khz is 80 mV P-P amplified signal is shown
> as an output signal (near Q4).  I must be missing something as it doesn't
> show how the RF signal coupled back to the input, unless of course C8 (the
> 1.0uf capacitor) is how it is coupled back.
> 
> 
> 
> There are several jumpers within the 8182 but the manual does not seem
> discuss these. The datasheet for the 8165 disciplined oscillator discusses
> on Page 5 about the "Switch A1S1" which will appears to enable/disable the
> DC preamplifier voltage.
> 
> 
> 
> https://www.atecorp.com/ATECorp/media/pdfs/data-sheets/Spectracom-8206_Manua
> l.pdf
> 
> 
> 
> Thanks
> 
> 
> 
> Donald Resor
> 
> N6KAW
> 
> 
> 
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