My good old Spectracom 8170 is not setting time. I don't use it for
frequency, just as a clock for my Hazetorium. I live about 20
minutes north of downtown Los Angles in Glendale. The antenna I'm
using is the Ferrite Rod loop in PVC that came with the 8170. It's
located on my back porch just laying on the floor with its maximum
pickup direction towards Boulder, Colorado. It has worked reliably
for many years in that location.
The symptoms are... One day about a month ago I noticed that it
seemed to be in the start mode, that is, the far left digit was
flashing between 0, 1, 2, and a lot of 4's, and the left most digits
were counting time since an apparent restart. Zeros and ones are the
logical data states, two is a place holder and four indicates data
errors. I'm not aware of it having lost primary power, but it's not
on a UPS. In a week's time it did not give me time sync, but shows a
green locked light most of the time. This happened several years ago
and a fellow at Spectracom told me to change all the electrolytics on
the one board that has only 4 electrolytics on it. I did and it
started to work just peachy-keen. The caps I put in then were of
good quality, but I decided to change them again. This did not solve
the problem.
The power supply voltages are all well within limits and they look
clean. I seem to have plenty of, but not too much, signal. By that
I mean it doesn't appear to be oscillating. The antenna is about 30'
away from the receiver on a piece of coax that appears to look
ok. What I do notice is that the signal looks like it's going
through quite a bit of turbulence. I do not see anything that looks
like interference. I've looked at the output of the filter amp
inside the 8170 and what I see is the signal dithering in amplitude
quite rapidly and sometimes squaring off for a moment - sort of what
you would expect to see during the Diurnal Shift periods of the
day. I can see the 10 dB drops, but they're not very clean due to
the rapid dithering. I've checked the antenna connections and tried
different azimuth headings. The location and azimuth it has been for
years still seems to be the best. Looking at the output of what I'm
guessing is a Schmitt Trigger, I see the ST's output jumping from 0
to +5, but erratically, which considering the received signal, makes sense.
I'm wondering if I'm just in a period of time that's receiving a poor
quality signal? It doesn't seem like WWVB's new phase-modulated
format should be causing this kind of a problem.
All observations, opinions and suggestions are welcome.
Thanks,
Burt, K6OQK
Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California U.S.A.
b...@att.net
www.biwa.cc
K6OQK
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