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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
Sabine,ALL, It is not the calibrator, nor SDRc2RSS, nor SDR Console. It is the difference between a consumer product and a scientific grade instrument. Highly accurate circuit design, quality parts, and an effort to achieve linearity are the difference. Here is the calibration plot from my $5k receiver.. Plot using Jim Sky's DIY Calibrator, Winradio WR G655DDCe receiver, SDR Console, SDRc2RSS, and RSS 2.9.80. The RSP1B is a suitable SDR for Radio JOVE Citizen science studies and is affordable for many young students. Thanks. Larry K4LED
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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
Sabine, It is not the calibrator nor SDRc2RSS nor SDR Console. Below is a plot from my $5k receiver.? It is the difference between a low cost consumer product and a scientific grade product with high quality linear parts and quality circuit design. The RSP1B is fine for Radio JOVE Citizen Scientist work given its reasonable cost many young students can afford. Plot using Jim Sky DIY Calibrator,?Winradio WR G65DDCe, on?SDR Console, SDRc2RSS, RSS 2.9.80. Thanks. Larry K4LED
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Re: The FFT and nuclear weapons
Dave, That's a very good history of the DFFT. I think you sent that video to me before and it's excellent. Thanks. It¡¯s amazing to me that current discoveries are actually based on work by others decades?ago. Gauss, Maxwell, Einstein, Hawking, Penrose (Roger is 93) and others had/have a gift of understanding far beyond anyone else. Why were they so gifted?? Einstein was rejected by every?university he applied to for professorship. Had to do humble work in a patent office to feed his family.? On a sad note I just read where USA sold our latest AI technology to the Arabs for a few $$$$. Scary thought. AI in unethical hands is dangerous to humanity. Same with Quantum computing technology. Those two technologies are set to change human life drastically.? Larry _______________________ On Mon, May 19, 2025 at 10:20?PM Dave Typinski via <davetyp=[email protected]> wrote: Here's a very interesting explanation of how and why the modern FFT came to |
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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
On Sun, May 18, 2025 at 01:12 PM, Huub Hameleers SWL/JO21JN wrote:
Not the most pretty curve I have to admit but I guess that's how the RX888 MKII behaves. When I look at the calibration curve that Chuck created with the RSP1B, I would suspect that the curve is messed up somewhere in SDRconsole or SDRc2RSS.
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Sabine
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Re: Calibration curve using RSP1B
Chuck, All, Chuck, yes that is not bad given that we are using consumer grade receivers, not scientific instruments.? \Foe receiving Jupiter's weak signals we want to emphasize the left bottom weak signal end of the calibration plot. On any receiver, if you want to hear the very weakest signals, turn the RF gain all the way UP to maximum. Sometimes even a small amount of low noise RF antenna preamp might help. SDR Console Settings: RF Gain 9 MAX? IF gain -45? Visual Gain -40 SDRc2RSS Settings As Shown.? Notice that the FFT Window is set to None and the dB Threshold is set to -150? Gain to 2 Typical RSS Calibration PLOT.? Not perfect but not bad. It could be improved with more adjustment time. RSS v Hope this helps. Larry K4LED
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Solar Events 19 May 2025, Prospect, ME
Good evening....two weak events....maybe
A lot of strong, local lightning recently.
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Off-topic...many evenings after submitting an events' report I'll turn on my ham radio and spend some time using FT-8
(digital mode) on the various bands starting at 10m (28.0 Mhz) then 12 m (24.9 Mhz), 15m (21.0 Mhz),....18Mhz, 14Mhz...down to 3.6Mhz.
The last few evenings here from 28 to 18 Mhz? I have heard & contacted almost no stations ANYWHERE....quite unusual.
Fun with radio. |
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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
Richard Inexpensive enough so worth a try,.20 dB may be too much and it might need a variable attenuator so you have control. Larry
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Re: Calibration curve using RSP1B
¿ªÔÆÌåÓýHi folks, ? ? I too am having trouble getting a good Cal curve. Using the standard Radio JOVE setup with the RSP1B receiver. I managed to get a decent Cal curve using these settings: ? RF Gain = 9 IF Gain = -45dB Visual Gain = -40 dB SDRc2RSS Gain = 2.0 ? Not quite linear, but not too bad. I did not adjust the Visual Gain per Richard¡¯s comment below, but maybe I don¡¯t understand it either. See screenshot below. ? Chuck ? ? ? ? From: [email protected] <[email protected]>
On Behalf Of Richard Gray via groups.io
Sent: Sunday, May 18, 2025 6:55 PM To: [email protected] Subject: [EXTERNAL] Re: [Radio JOVE] Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025 ? Hi Larry, ? Our RX-888s run a bit warm to the touch, but not hot.?? We could certainly get some small fans that run from a USB port.?? Are you thinking that if we cooled the RX-888s that that would bring the bottom of the curve down to the bottom of the graph?? That seems a rather large effect.? We got our RX-888 MK IIs from the source you recommended, not off of eBay or Amazon.? They appear to be the real thing and operate almost identically.? Unfortunately, that source is no longer selling RX-888s into the US market because of the tariffs on Chinese goods. ? We managed to push the curve down by lowering the "visual gain" to -30dB.? That was surprising to me because from what I have read, the visual gain should only affect the display on SDRconsole and not the output from the SDR, but it had a very clear effect on the RSS spectrogram and the calibration curve as well.? It is not possible in SDRconsole to lower the visual gain below -30dB.?? One can get the curve lower by lowering the "HF gain" in SDRconsole.? In both cases it is then necessary to raise the gain in SDRc2RSS to get the top of the curve back up to the top of the graph.?? However, I feel that I am twiddling knobs without fully understanding their function. ? Richard |
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Re: Solar and RF fadeout North Tasmania, Australia
Hi Sabine,
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For those inflicted with RFI -- i.e., most of us -- sadly, windowing is absolutely necessary. As you said, FFT leakage is a concern for coherent emission -- like radio stations and radar. However, for emission made up of noise -- all cosmic emission so far discovered -- a rectangular window (i.e., no window) works quite well. In fact, it's preferred not to use windowing for noise emission because use of a window function on emission made of noise does nothing but attenuate the signal. Unfortunately, the use of a rectangular window requires that one have very quiet observing conditions, otherwise any RFI -- which is mostly coherent emission -- will splatter into neighboring bins, as you said. For example, Richard's station is very quiet. I bet he could run with no windowing at night -- i.e., when terrestrial propagation is not present. More here on why this is so for noise vs coherent emission: ,%20Typinski%20(RJ,%202014)%20Slides%20and%20Notes.pdf -- Dave On 5/19/25 10:23, Sabine Cremer wrote:
Larry, |
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Re: Solar and RF fadeout North Tasmania, Australia
Sabine, Yes your technically correct the FFT window is always on but you can select or deselect the various filter algorithms. Thanks. Larry _______________________ ? On Mon, May 19, 2025 at 10:23?AM Sabine Cremer via <sc=[email protected]> wrote:
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Re: Solar and RF fadeout North Tasmania, Australia
Larry,
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shortly after sending the message, I felt like I'd already started this discussion before. Sorry if I'm annoying.
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By the way, windowing can't really be turned off. Without one of the windows with the evocative names (Tukey, von Hann, Blackman, etc.), a rectangular window acts on the FFT wave train, producing familiar artifacts such as excessive leakage of signals with high magnitudes into neighboring bins.
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Sabine
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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
Hi Richard,
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I've done some more testing today.?
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Moving the band-scope ?lower or higher didn't make any difference. Same calibration curve everywhere. That's a good thing I guess.?
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Then I fiddled a bit more with the controls and got a reasonable result. Attenuation is now set to zero in sdrconsole. See attached images for the settings.
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Regards,
Huub
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Re: Views of the Solar "Storm" from the Dark Sky Observatory May 13, 2025
Hi Richard,?
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This morning I realised I should have given you the full picture about the full bandwidth image I send you. So I zoomed in to the Jove band on my RX888 (RX2FITS) recording (the darker part) as well as on my RSPDUO recording. Both use the same antenna. As you can see the signals are there. Compared to my RSPDUO setup the RX888, in my opinion, performs very good. The dynamic range of the RX888 is bigger due to the 16 bits ADC which explains the huge differences in the full bandwidth image.
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Attached 5 images. first two from the RX888 (RX2FITS). Image 3 and 4 from RSPDUO calibrated setup. Lastly a spectrum plot of the full bandwidth recording.
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Today I will return to the sdrc setup to do another calibration run on a different band span.
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Huub |
Larry Dodd
john sommer
Alfi Hasan
Sabine Cremer
Dave Typinski
Chuck Higgins
