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

[jimlux]

On 10/5/20 3:59 AM, Magnus Danielson 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.
> 

And, just as with Omega (10-15 kHz) the height of the ionosphere changes 
the effective height of the "waveguide" through which the surface wave 
propagates.