[time-nuts] RFDO - Experience and questions

paul swed paulswedb at gmail.com
Tue Mar 7 12:52:36 EST 2017

I went back over the starting thread and believe your home brew oscillator
may prevent you from getting all of the accuracy out of TDF.
As I was thinking about a TRF radio and locking the question I arrived at
is how do you turn 162KHz into something useful like 100 KHz 5 MHz or 10
By getting to standard references there are many very good oven oscillators

On Mon, Mar 6, 2017 at 10:35 PM, paul swed <paulswedb at gmail.com> wrote:

> Actually as I think about it from the earlier part of the thread. Locking
> to the carrier with a 2-4 second time constant removes the phase modulation
> since its only in the first 200 ms. The 0 Phase is 800 ms in length or more
> for all bits.
> Now to find some nice coils for 162 KHz.
> Regards
> Paul
> On Mon, Mar 6, 2017 at 8:30 PM, paul swed <paulswedb at gmail.com> wrote:
>> A bit more reading if you block the phase comparison from -50ms to 150ms
>> of the tick you get a 0 carrier phase no modulation. That also explains why
>> I thought I could here some sort of phase modulation because there is.
>> So as an example if you use a GPS tick its really simple to block the
>> phase changes and only measure the 0 phase carrier. Essentially a 200 ms
>> carrier gap per second.
>> Thats quite a clean format you have to work with.
>> Regards
>> Paul
>> On Mon, Mar 6, 2017 at 8:19 PM, paul swed <paulswedb at gmail.com> wrote:
>>> I checked out 162KHz at 2000 local and now have what I believe to be TDF
>>> using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the
>>> US or 3400 miles. A comfortable signal at least in the winter. As a
>>> comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW
>>> power level like TDF.
>>> Since I had not heard TDF before I listened to Pieters online SDR radio
>>> to see what to listen for. The easiest point to notice is the 59 second
>>> phase. Its funny that also seconds 0-10 should be the same phase but it did
>>> not seem to be true. Unless what I am hearing is the local oscillator of
>>> Pieters SDR radio.
>>> So thanks for sharing some new knowledge with Time-nuts.
>>> Regards
>>> Paul
>>> WB8TSL
>>> On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
>>> ptdeboer at cs.utwente.nl> wrote:
>>>> On Sun, Mar 05, 2017 at 10:42:52PM +0000, Iain Young wrote:
>>>> > That's TDF from France. Their equivalent of WWV/MSF/DCF.
>>>> > Average phase and frequency deviation is
>>>> > zero over 200msec (see link above for details)
>>>> This is not quite correct, since the transmitter does not just carry the
>>>> time data (one bit per second, in the first 200 ms of the second), but
>>>> also some more data during the next 700 ms of each second.
>>>> The latter data is coded in a way which does not guarantee that the
>>>> phase
>>>> or frequency average is zero other than when averaging over the entire
>>>> 700 ms block.
>>>> Then again, I've been told that although there is a nicely defined
>>>> framing
>>>> format, in reality it has only ever transmitted idle frames, so in
>>>> practice
>>>> it's a fixed pattern which repeats every minute and thus could be
>>>> cancelled
>>>> for use as a frequency reference.
>>>> I have a live online decoder for TDF's signal at
>>>>    http://websdr.ewi.utwente.nl:8901/tdf/
>>>> Regards,
>>>>   Pieter-Tjerk, PA3FWM
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