[time-nuts] Spectracom 8161 "Standard Frequency Receiver - Oscillator" for WWVB (and question...)

[Bob kb8tq]

Hi

You *are* talking about a 60 KHz sine wave when playing with WWVB. The
typical receiver had a fairly narrow passband. This generally was accomplished
with both high Q tuned circuits and a crystal filter. The typical antenna loop antenna
also had a fairly high Q tune on it. Even if the signal was perfect, the receiving
setup would have struggled once you got into the small fractions of a cycle sort of
region ….

For that matter, the matching network at the base of each of the transmit antennas 
has some pretty big tuned elements in it. They most certainly “chug” around any
time the “breeze” blows in Colorado ( = most of the time …. :) ). 

Propagation at 60 KHz is also impacted by the weather. Push a cold front with a 
bunch of thunderheads into the path and you get a blip in the delay. Lots of other
things get into that mix as well.

Lots of variables …..

Bob

> On Oct 5, 2020, at 9:52 AM, paul swed <paulswedb at gmail.com> wrote:
> 
> Hal and Magnus its pretty interesting. WWVB is indeed a skywave behavior
> further out and at night. It exactly behaves like LORAN C and DCF and
> others. But during the day I think it generally behaves like ground wave
> from what I have experienced. What seems to be interesting is that the day
> to day is somewhat repeatable. There was a NIST and HP document back in the
> 1960-70s time ( Think its in the hp vlf117 manual also)that talks about day
> to day use for longer measurement periods. I was surprised by the details.
> Also consider the time frame most oscillators were low stability back then
> and the Cesiums were coming into play.
> Fun history.
> Regards
> Paul
> 
> On Mon, Oct 5, 2020 at 8:18 AM Magnus Danielson <magnus at rubidium.se> wrote:
> 
>> Hi,
>> 
>> On 2020-10-05 11:20, Hal Murray wrote:
>>>> On a WWVB setup you get 10’s of us ( yes microseconds) of movement at
>>>> sunrise and sunset. You get as much as 10us between day and night.
>>> Somehow, I was thinking that WWVB was ground wave and wouldn't be
>> effected by
>>> changes in the height of the ionosphere.  Am I totally out of it, or is
>> 10s of
>>> uSec just a lot better than the day/night shift you get with WWV?
>> 
>> You will for sure see a mix of ground wave and ionspheric reflection,
>> and those will vector sum. Depending on your distance your milage may
>> vary. The same is seen at 77,5 kHz (DCF77) and 100 kHz (LORAN-C). The
>> solar flare effect documented in the 8161 manual is for sure an
>> ionspheric reflection effect.
>> 
>> Cheers,
>> Magnus
>> 
>> 
>> 
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