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Post by Deleted on Dec 17, 2016 18:29:36 GMT
During those years in licensed radio a tradition existed among stations who all picked Sunday overnight to schedule maintenance that required shutting down the transmitter.
Some stations switched to auxiliary transmitters so they retained air presence while safely tinkering with the main transmitter, but the Sunday night programming on all the stations seemed to be minimal time-filler and not fully staffed.
In our low power world it's the computer, not usually the transmitter, that needs to be shut-down for maintenance, with everything from re-booting, updating software and dusting the crevices.
One week I picked Saturday for a shut-down, intending to dismantle and rebuild the main work station with new shelving to relieve crowding, but it wasn't back up in time for the ALPB Meeting, although Chairman Felmly was able to get me in by use of his newly built telephone hybrid device.
Now again it's a Saturday and history came very close to repeating itself as I want to shut-down for a computer cleanup and inspection, but I remembered that tonight again is an ALPB meeting night so I have decided to remain online and do the engineering work tomorrow.
When does your station do shut-down maintenance?
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Post by Admin on Dec 20, 2016 2:44:28 GMT
My main PC running XP has to be rebooted about twice a week as the RAM slowly becomes unavailable.
My only concern is the TeamSpeak server as I wouldn't want to interrupt any live operations.
A reboot also affect my home hosted webpage, my Part 15 FM, The ALPB Mini Seminars Video server and a couple other less critical apps.
If too much RAM becomes unavailable the PC locks up and most server functions stop. Not good...
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Post by Druid Hills Radio on Dec 20, 2016 15:45:21 GMT
My main PC running XP has to be rebooted about twice a week as the RAM slowly becomes unavailable. My only concern is the TeamSpeak server as I wouldn't want to interrupt any live operations. A reboot also affect my home hosted webpage, my Part 15 FM, The ALPB Mini Seminars Video server and a couple other less critical apps. If too much RAM becomes unavailable the PC locks up and most server functions stop. Not good... |
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Post by Deleted on Jan 31, 2017 17:57:55 GMT
Kinds of Leaks
Leaky memory is a resemblance between humans and computers. We end up remembering anything that hasn't leaked.
I recall today's plan involving the AMT3000 over there under the corner of the desk at the window which seems to have bandwidth leak two channels out both above and below the main carrier.
The transmitter sends KDX at 1550 kHz, and last night I tuned above up to 1570 and heard some unusual Mexican instrumental music but mixed on top of it was a "woo-wow-woo-wow" frequency that also appears at 1530 kHz.
When this happens it means that some high frequency outside of the 10 kHz audio bandwidth is modulating the transmitter way out-of-channel.
The audio feed line from the computer audio-output to the transmitter audio-input is a 25-foot unbalanced shielded cable.
We realize that unbalanced audio lines should not be more than 6-feet long to preserve best results, and for longer audio runs it is advisable to employ balanced audio lines, which I have not yet done in this case.
There are no upper audio frequencies causing this "unwanted upper-audio-band interference" so we suspect it is the shielding of the audio cable picking up the 1550 kHz signal and putting it into the audio input.
The AMT3000 has some handy filter-inductors that can be switched into the audio-line for the very purpose of squashing high frequency feedback, so today we'll give it a try.
On a sometime day we'll build a balanced audio system to finish the job.
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Post by Deleted on Feb 2, 2017 17:17:17 GMT
Memory Leak in the Head
Talk of "memory leaks" came into this thread when Admin up above described his computer's leaking memory problem.
Then I swung to the out-of-channel "leaking" audio believed to be introduced from the 25-foot unbalanced audio line connecting the AMT3000 with the computer's audio output plug.
This morning I can tell you the results of taking a fresh look at the problem... to re-discover a problem that was first identified a year or so ago... forgotten now due to leaking memory in my head.
Somewhere there is an old thread about a "ticking sound" being heard at 1530 & 1570 kHz, above and below my 1550 kHz signal. It was found to be the switching power-supply module of the Epson Desktop Scanner. By unplugging the scanner the "ticking" went away.
What I found at that time was that moving the power-module to a different AC plug the ticking was reduced to a "woo-wah-woo-wah tone". It is so weak it does not show up on the spectrum analyzer, and by installing a balanced audio line it will be completely eliminated.
The Epson Scanner power-wart does not interfere with any other operation.
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