In a message dated 21/02/03, jpeakall@............ writes:

> Neat looking units. Have you interfaced a micro with these? If so, what 
> 

Hi Jonathan,

       If you call up http://www.hkw-elektronik.de/pdf/fbw13010_dd.pdf you 
will get a description of the WWVB receiver. It can be configured to give +ve 
or -ve output pulses following the format of the WWVB signal, which are of 1 
pulse per second, but different lengths. There is an AVC line which follows 
the signal strength and provides the zero signal level reference. Note that a 
crystal filter is used, which provides very narrow band reception. HKW also 
do a decoder chip which takes in the signal and gives out RS232. Note that 
WWVB, MSF, DCF and JJY are all different time formats. Two ferrite rod 
aerials are available, 60 mm or 100 mm long.   

       Larry has a note on WWVB at http://www.seismicnet.com/wwvbsdr.html and 
has modified software to drive the card. Boulder give a time accuracy to 
within 0.1 milli second with a good receiver. The errors due to changes in 
radio signal path are generally much less that with WWV.

       I do not know if these very narrow band receivers will work all over 
the US, but Boulder have increased the transmitter power to 50 KW. Maine is 
about 1900 m from Boulder, so it must be getting near the limit. I use DCF 
and it is very reliable, but I am only about 650 km from the transmitter ~400 
m. Night time reception of DCF is quoted to 3000 km ~1900 m and daytime 
reception to 2000 km, which I can confirm. I checked my receiver sensitivity 
and to stop it working, I had to put it in a tin box and close the lid. And 
there are places in my house where you cannot get FM or even good MW radio 
reception. These very long wave signals seem to bend around mountains fairly 
well. I suggest that you look up http://www.boulder.nist.gov/timefreq/ for a 
lot more useful information.

       Regards,

       Chris Chapman
In a message dated 21/02/=
03, jpeakall@............ writes:



Neat looking units. Have yo=
u interfaced a micro with these? If so, what micro did you use? What format/=
baud rate does the data come in?



Hi Jonathan,



       If you call up http://www.hkw-elekt=
ronik.de/pdf/fbw13010_dd.pdf you will get a description of the WWVB receiver=
.. It can be configured to give +ve or -ve output pulses following the format=
 of the WWVB signal, which are of 1 pulse per second, but different lengths.=
 There is an AVC line which follows the signal strength and provides the zer=
o signal level reference. Note that a crystal filter is used, which provides=
 very narrow band reception. HKW also do a decoder chip which takes in the s=
ignal and gives out RS232. Note that WWVB, MSF, DCF and JJY are all differen=
t time formats. Two ferrite rod aerials are available, 60 mm or 100 mm long.=
   



       Larry has a note on WWVB at http://=
www.seismicnet.com/wwvbsdr.html and has modified software to drive the card.=
 Boulder give a time accuracy to within 0.1 milli second with a good receive=
r. The errors due to changes in radio signal path are generally much less th=
at with WWV.



       I do not know if these very narrow=20=
band receivers will work all over the US, but Boulder have increased the tra=
nsmitter power to 50 KW. Maine is about 1900 m from Boulder, so it must be g=
etting near the limit. I use DCF and it is very reliable, but I am only abou=
t 650 km from the transmitter ~400 m. Night time reception of DCF is quoted=20=
to 3000 km ~1900 m and daytime reception to 2000 km, which I can confirm. I=20=
checked my receiver sensitivity and to stop it working, I had to put it in a=
 tin box and close the lid. And there are places in my house where you canno=
t get FM or even good MW radio reception. These very long wave signals seem=20=
to bend around mountains fairly well. I suggest that you look up http://www.=
boulder.nist.gov/timefreq/ for a lot more useful information.



       Regards,



       Chris Chapman