Signal Quality Log
The Netclock/2 has a built-in Signal Quality Log. A laptop PC running HyperTerminal or Procomm and a standard straight-thru Serial cable are required to obtain the log. Sending a capital letter R to the clock outputs the Signal Quality Log report. The report contains an hourly count of good compare minutes and the number of times phase lock to WWVB was lost over the last 24 hours. The report is updated at the end of each hour and continuously overwrites previous data contained in that hour location. An example of the Signal Quality Log is shown below:
| Signal Quality Log |
| Hour End |
Compare Minutes |
Lost Lock Counter |
Hour End |
Compare Minutes |
Lost Lock Counter |
| 0 |
60 |
00 |
12 |
60 |
00 |
| 1 |
59 |
00 |
13 |
60 |
00 |
| 2 |
60 |
00 |
14 |
60 |
00 |
| 3 |
60 |
00 |
15 |
60 |
00 |
| 4 |
60 |
00 |
16 |
60 |
00 |
| 5 |
60 |
00 |
17 |
60 |
00 |
| 6 |
60 |
00 |
18 |
49 |
01 |
| 7 |
60 |
00 |
19 |
34 |
00 |
| 8 |
60 |
00 |
20 |
60 |
00 |
| 9 |
60 |
00 |
21 |
60 |
00 |
| 10 |
60 |
00 |
22 |
60 |
00 |
| 11 |
60 |
00 |
23 |
60 |
00 |
The Hour End column in the report represents display time. Display time may be UTC or local time depending on how the clock was initially set up. Clocks displaying UTC time have the TIME ZONE offset switches set to zero and the automatic DST correction feature disabled.
The Compare Minutes is the number of error free minutes accumulated over each one hour period. The WWVB time code is one minute in duration and consists of 60 characters. The Netclock/2 receives this code and qualifies each character received. If a received character is ruled invalid, the Compare Minutes counter is not incremented for that minute. Invalid characters or bit errors are primarily due to poor atmospheric conditions. Local interference, solar flares, and poor antenna location or position may also contribute to a high bit error rate, resulting in a low compare minutes count.
The Lost Lock Counter is incremented each time carrier lock to WWVB is lost over that one hour period.
Print the log at about the same time for several days in a row to determine if there is a pattern to the reception. Contact Spectracom tech support for assistance with evaluating the Signal Quality Log.
The Clear Buffer command is used to restart the Signal Quality Log. Sending the capital letters CB resets the Compare Minutes and Lost Lock Counter to all zeroes.