[time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

10 MHz *is* a frequency at which you can find a pretty good $3 to $6 OCXO.
I find that a bit amazing, but (at least right now) that’s how it seems to work.
(and yes, they do have EFC). 

Bob


> On Jul 22, 2020, at 10:09 PM, paul swed <paulswedb at gmail.com> wrote:
> 
> Looked at the KD2BD schematic and it is a 10 MHz VCTCXO. That seems
> reasonable perhaps to find.
> Regards
> Paul
> 
> On Wed, Jul 22, 2020 at 6:44 PM paul swed <paulswedb at gmail.com> wrote:
> 
>> I was actually thinking about this quite a bit and perhaps I went the
>> wrong way.
>> That is a cheap vcxo class device. His unit was not an oven as I recall.
>> Just maybe a bit too good was actually bad.
>> Hard to say and no time to play right now.
>> Regards
>> Paul
>> WB8TSL
>> 
>> On Wed, Jul 22, 2020 at 6:06 PM Bob kb8tq <kb8tq at n1k.org> wrote:
>> 
>>> Hi
>>> 
>>> 
>>> 
>>>> On Jul 22, 2020, at 3:51 PM, paul swed <paulswedb at gmail.com> wrote:
>>>> 
>>>> Ray watch out for my comment on the KD2BD solution. That oscillator
>>> isn't
>>>> available and I have not been able to map something else into it. Tried
>>>> several good grade Oven oscillators. Just be aware of that issue.
>>>> Would need to do more tinkering and simply don't have that time right
>>> now.
>>>> Also it would be great if the oscillator was something that could be
>>>> obtained at a reasonable cost. I do not believe at all it has to be a
>>>> OCXO as the older true time and spectracoms were not and they locked
>>> solid.
>>>> So its a case of getting the control voltages right.
>>> 
>>> You can buy a surprisingly good little OCXO (for the price) on eBay these
>>> days in the  $3 to $6 range. Find one at 12.6 MHz and it will divide
>>> nicely to
>>> 60 KHz. 19.2 MHz looks like a better candidate … Either way I have not
>>> (yet)
>>> seen a 60 KHz multiple show up in the cheap category.
>>> 
>>> Bob
>>> 
>>> 
>>>> Regards
>>>> Paul.
>>>> 
>>>> On Wed, Jul 22, 2020 at 3:29 PM <rcbuck at atcelectronics.com> wrote:
>>>> 
>>>>> Thanks to all for the suggestions. I dug a ferrite rod AM radio antenna
>>>>> out of the box this morning. I have a box of 10 left over from the late
>>>>> 80s. It measures 0.950 mH so I will add some turns to get it to 1.5 mH
>>>>> which will be easier to resonate at 60 kHz. Then I need to build up the
>>>>> RF amp and run the output through a 60 kHz crystal filter. I have to
>>>>> order the crystals since I don't have any on hand. It will take a
>>> couple
>>>>> of weeks to get the front end working.
>>>>> 
>>>>> I am in Phoenix so the WWVB signal is of decent quality here even
>>> during
>>>>> the daytime. My 25 year old cheap Casio watch will sync up within 2-3
>>>>> minutes any time of day or night. It normally syncs at 2 am but I have
>>>>> done tests to confirm daytime sync works reliably.
>>>>> 
>>>>> Mark, I know virtually nothing about SDR other than it works. I bought
>>> a
>>>>> RTL-SDR.Com module a couple of years ago and played with it a little
>>>>> bit. But it quit working and I haven't thought about SDR since then. My
>>>>> Icom 7300 is a SDR and it works very well. I think to attempt to design
>>>>> a SDR would be well over my head. I anticipate this project taking 2-3
>>>>> months. If I get it working I will be glad to share everything with the
>>>>> group.
>>>>> 
>>>>> Lester and Paul, I will test with the Costas loop as it may be the
>>>>> easiest way to go. To test the Costas loop I am basically going to
>>>>> duplicate the KD2BD design. I was reluctant about it in the beginning
>>>>> but more reading seems to indicate it will be fine. My AWG allows me to
>>>>> set the phase from 0 to 360 degrees independently on each channel so I
>>>>> can use that for initial testing. That testing can be done prior to
>>>>> getting the front end working.
>>>>> 
>>>>> Richard, is your software posted somewhere? I assume it allows you to
>>>>> specify the time and date you want it to send. That would come in handy
>>>>> for writing the code to extract the timer/date data. I have seen
>>>>> examples of the Arduino transmitting the old AM signal but don't recall
>>>>> seeing one that sends the BPSK stream.
>>>>> 
>>>>> I have a GPS time receiver with a 1.2 inch LED display that I built a
>>>>> couple of years ago. I have it setup so the UART outputs the gprmc NEMA
>>>>> string in case I want to look at it. I have a couple of spare GPS
>>>>> modules lying around and several Arduino Uno modules. I have no problem
>>>>> picking up the GPS satellites using only the patch antenna that is
>>> built
>>>>> into the modules.
>>>>> 
>>>>> Ray,
>>>>> AB7HE
>>>>> 
>>>>> 
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