Chris,

Thanks for all the info. I would like to try to see what my signal =
strength is with these various stations is. Maybe I can borrow a =
receiver and find out. My link to WWVB is still more dodgy than I would =
like. I am in northern California and not TOO far from WWVB, but I live =
in a "black hole" of RF. My fire dept. pager often doesn't go off at =
home, and I am pretty close to the transmitter. As soon as I get a mile =
down the road it is much better.

Jonathan


  ----- Original Message -----=20
  From: ChrisAtUpw@..........
  To: psn-l@.................
  Sent: Friday, February 21, 2003 5:45 PM
  Subject: Re: Atomic Time Source for data logging


  In a message dated 21/02/03, jpeakall@............ writes:=20


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


  Hi Jonathan,=20

        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.   =20

        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.=20

        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.=20

        Regards,=20

        Chris Chapman=20







Chris,
 
Thanks for all the info. I would like =
to try to see=20
what my signal strength is with these various stations is. Maybe =
I can=20
borrow a receiver and find out. My link to WWVB is still more dodgy than =
I would=20
like. I am in northern California and not TOO far from WWVB, but I live =
in a=20
"black hole" of RF. My fire dept. pager often doesn't go off at home, =
and I am=20
pretty close to the transmitter. As soon as I get a mile down the road =
it is=20
much better.
 
Jonathan
 
 

  
----- Original Message ----- 
  From:=20
  ChrisAtUpw@....... 
  
To: psn-l@.............. 
  
Sent: Friday, February 21, 2003 =
5:45=20
  PM
  
Subject: Re: Atomic Time Source =
for data=20
  logging
  

In a =
message dated=20
  21/02/03, jpeakall@............=20
  writes: 


  Neat looking units. Have you interfaced a micro with =
these? If=20
    so, what micro did you use? What format/baud rate does the data come =

  in?

Hi Jonathan,=20
  

      If you call up http://www.hkw-=
elektronik.de/pdf/fbw13010_dd.pdf=20
  you will get a description of the WWVB receiver. It can be configured =
to give=20
  +ve or -ve output pulses following the format of the WWVB signal, =
which are of=20
  1 pulse per second, but different lengths. There is an AVC line which =
follows=20
  the signal strength and provides the zero signal level reference. Note =
that a=20
  crystal filter is used, which provides very narrow band reception. HKW =
also do=20
  a decoder chip which takes in the signal and gives out RS232. Note =
that WWVB,=20
  MSF, DCF and JJY are all different time formats. Two ferrite rod =
aerials are=20
  available, 60 mm or 100 mm long.   =20
  

      Larry has a note on WWVB =
at=20
  http://www.seismicnet.com/wwvbsdr.html and has modified software to =
drive the=20
  card. Boulder give a time accuracy to within 0.1 milli second with a =
good=20
  receiver. The errors due to changes in radio signal path are generally =
much=20
  less that with WWV. 

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

      Regards,=20
  

      Chris Chapman=20