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Re: How much do your calibrations vary?
¿ªÔÆÌåÓýJim Yes good idea Jim. I have voltage regulators on each calibrator voltage line, 12v, 5v, and 3.3v and I can tell you they do drift slightly over months of time. Have not charted that but might be another source of change. I have to tweak them a few hundredths or tenths of a volt every month or two but seldom more than a volt. I keep an external box fan ?on 24/7 behind the desktop JOVE computers and calibrator. I have one older Dell that the power supply is slightly under sized and it runs hot. These new NVIDIA graphic cards are power hungry. When you purchase new computers its wise, I found out, to select largest power supply available. Even more of an issue for those running laptops. With radio room ?HVAC temp control and fan for additional circulation, temp never varys in the radio room much more than two degrees. I have one experimental test equipment box I fabricated ?that's ?temperature controlled with peltier thermoelectric modules and PT100 sensitive platinum RTD temperature sensors that can regulate its metal cabinet temp to less than one degree.? Jim your new calibrator board should be super stable.? Larry On Mar 10, 2025, at 1:10?AM, Dave Typinski via groups.io <davetyp@...> wrote:
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Re: How much do your calibrations vary?
¿ªÔÆÌåÓýThis is an outstanding line of
investigation, Jim!? Excellent idea.
-- Dave On 3/10/25 00:47, Jim Sky wrote:
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How much do your calibrations vary?
For those who have ongoing observations and working calibrators,? I would like to ask a favor.? I want to see how much your calibrations vary over time.? If you have the calibrator running automatically every observation changes in the calibration plot will probably show some "thickening" indicating the amount of variance over several days.? Watching that display can give some confidence that things have not changed due to a problem in the telescope. Below is a copy of my calibration plot for my dipole over 10 consecutive days.? It is hard to know where this variation comes from, the receiver or the calibrator.? My experience has been that the SDRPlay 1A really requires an hour warmup to fully stabilize, which would indicate some temperature dependency probably even after the warmup.? The noise generator inside probably has some power drift with temperature and may have some sensitivity also to changes in it's power supply voltage. While it would be good to sort out the source of calibration plot variation, I am mostly interested in setting realistic error bars to our measurement.??
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If you can, please post a screenshot of your calibration chart (like mine below) after it has run uninterrupted for 10 or more days.? Also I would like to have your best guess at how much temperature variation your receiver and calibrator experienced from night to night when the observation started.? For example, my setup is in a partially heated room that experienced big differences from night to night during the period shown on the plot and I estimate it experienced about 8 degrees C from night to night.? ?I am interested in the temperatures when the calibration was performed, not throughout the day.? If your house has a well regulated heating system your system might experience less than a degree of variation between calibrations.
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Thanks!
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Jim Sky?
radiosky at radiosky dot com |
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Re: Some non-Io-A from tonight March 09 2025
Very nice non-Io-A, Richard.
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The increasing frequency circa 2244 to 2252 UTC is interesting. That may say more about the ionosphere than the arc shape. Non-Io-A is always vertex late (negative freq drift). Non-Io-B is RCP and has a positive freq drift -- but it would be very strange, albeit not impossible, to see non-Io-B emission way over in the non-Io-A zone. Most likely that positive rate was due to ionospheric effects. Sometimes the emission can appear to have drift rate opposite of what's expected across a MHz or three if ionospheric dynamics decide to join the party. I suspect that's what's happening here. When the analysis is zoomed out to a half hour or more and to 10 MHz bandwidth or more, then the true arc shape becomes more apparent. -- Dave On 3/9/25 21:31, Richard Gray via groups.io wrote:
I think this is classified as non-Io-A. This is from earlier tonight. |
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solar (?) on 08/09 March
Good day all! Received odd/interesting captures that I would like to toss out there. File 250308223429 Is this soler or maybe Jove. Both in a good postion. File 250308232336 Also Both in good position, Upper Band Solar? File 250309003813 Upper Band Solar?? I haven't seen many of these at my location, so my experience is quite low. Thanks for any feedback! Carl Wasilla AK, USA UTC-9 |
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Re: Io-B March 8 2025
Fantastic captures! Well Done Richard Carl On Sun, Mar 9, 2025 at 3:26?AM salvador aguirre via <drsaguirre=[email protected]> wrote:
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Larry Dodd
Dave Typinski
Jim Sky
salvador aguirre
Carl Pajak Phone
