[ntp:questions] Re: CHU time source?
Ross
rwa at aukward.bogons
Fri Dec 31 06:47:22 UTC 2004
shoppa at trailing-edge.com writes:
> You're in Toronto, the CHU transmitters in Ottawa, only 250 or 300
> miles away. You'd probably get pretty good reception continuously on
> either 3.33MHz or 7.335MHz.
I lived in Trenton, Ont. in the 60's. CHU is a ton of bricks all over
southern Ontario.
> I don't have any experience with audio refclocks under FreeBSD, but it
> "oughta work". It took me a little bit of tinkering to make it work
> with Linux, see
I've run both the CHU and WWV clocks from my present QTH of Edmonton, and
FreeBSD is very happy with them. I did some butchery in the PCM code to
get better control over the audio source and AVC, but that was pretty much
cosmetic. CHU turns out to be quite jittery and I've elected to go with
WWV since I've only got one (non-agile) receiver that I can dedicate.
Right now, on the radio clock machine (aubey.bogons)
ntpq> lpeer
remote refid st t when poll reach delay offset jitter
==============================================================================
*WWV_AUDIO(1) .WV20. 0 l 15 64 377 0.000 -0.098 0.069
ntpq> cl
status=0101 clk_noreply, last_clk_noreply,
device="WWV/H Audio Demodulator/Decoder",
timecode=" 4 2004 366 06:26:59 S -5 0 255 WV20 6 38 78.6 1024",
poll=1611, noreply=547, badformat=0, baddata=0, fudgetime1=5.220,
stratum=0, refid=WV20, flags=14
ntpq> rl
status=0284 leap_none, sync_lf_clock, 8 events, event_peer/strat_chg,
version="ntpd 4.1.73 at 1.982-r Sat Apr 17 22:52:07 MDT 2004 (1)",
processor="i386", system="FreeBSD/5.2.1-RELEASE-p8", leap=00, stratum=1,
precision=-20, rootdelay=0.000, rootdispersion=2.832, peer=61580,
refid=WV20, reftime=c57f6f78.03e4d4a2 Thu, Dec 30 2004 23:26:00.015,
poll=6, clock=c57f6faf.6ad491df Thu, Dec 30 2004 23:26:55.417, state=4,
offset=-0.098, frequency=-46.083, jitter=0.052, stability=0.000
(although it's 23:30 local and the 19 meter propagation is marginal right now);
and from a neighbour on the same LAN,
% ntpq -c lpee
remote refid st t when poll reach delay offset jitter
==============================================================================
*aubey.bogons .WV20. 1 u 4 64 377 0.307 -0.036 0.001
-dense.utcc.utor 128.100.96.226 2 u 174 256 377 47.375 -2.935 0.122
-ensb.cpsc.ucalg 18.26.4.105 2 u 115 256 377 17.361 -2.296 0.328
-ntp.ubc.ca 140.142.16.34 2 u 45 256 335 26.238 -0.666 0.880
-f02s01.tac.net 204.34.198.41 2 u 140 256 377 15.621 -1.595 0.495
-time1.chu.nrc.c 209.87.233.50 2 u 125 256 377 95.124 -10.064 5.311
Not bad for home-entertainment-grade ADSL and a garage-sale sw receiver.
regards,
Ross
More information about the questions
mailing list