[DSP-10] Sun Noise Measurement

Tue Nov 1 10:05:26 EDT 2016

> On Nov 1, 2016, at 12:25 AM, Bob Larkin <boblark at proaxis.com> wrote:
> 
> Hi Courtney  -  Your note  got me to check with the ARRL and so I have been able to post a copy of the 2003 MUD paper, "The Use of  the Sun, Quiet Sky and Earth Nois Measurements for Determining System Paramenters with Error Analysis," at
> http://www.proaxis.com/~boblark/Sn_MUD3A_3.pdf

Got it - will try to make time to read it at lunch today or soon anyway.

> 
> Additionally, I had never done an on-line Javascript calculator, so I moved the Basic program from the paper into that form.  It is a tad experimental yet, but I think is OK.  Any problems have to do with with browser differences.  The math part I'm quite sure is correct.  It has been a worthwhile learning experience, and the result may be useful:
> http://www.proaxis.com/~boblark/Calc_SQE.html
> That links a second calculator for working with on-line Sun flux data. I would appreciate reports of browser problems from anybody.
> 
Looks good to me.  Test calculations I did agree with other sources I’ve used.  I was also able to get nonsense output by accidentally typing nonsense input but that’s expected and I wouldn’t do any work to “protect” the inputs from typos.  I’m always worried about getting the math right, the user interface issues further down the list.

I have bookmarked it and will use it when I do updated measurements.  Unclear when I can attempt sun noise again since it’s nearly winter and the sun is down in the trees most of the time.  But we’ll see what I can do.

> Is your AMSAT paper available?

I don’t know that it’s ever been posted officially, AMSAT is not always that organized.

It appears that you can get it from my “phase five” web page at http://cbduncan.duncanheights.com/HamRadio/Dsp10/PhaseFive/PhaseFive.html but I haven’t maintained it in a long time, so I attached a PDF from my shadow site on this computer.
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Having reviewed the paper a few times in the last few years, I found a few math or assumption errors.  Also, I have done other calculations in years since and haven’t fully convinced myself that this experiment should have worked, but I suspect it did because the post processing program I wrote “cherry picked” the data points by limiting the maximum noise allowed into the average, something DSP-10 Alt-F data facilitates.  I still plan to figure out what I really did one of these days when I understand everything well enough.

Note, I’ve been off earthlink for years.  Reference 2 is broken.  The closest equivalent now is http://cbduncan.duncanheights.com/HamRadio/Dsp10/Dsp10Legacy.html

Also, the ARRL website crashed in the intervening time so most of those links may be broken too.

Courtney

> 
> 73, Bob  W7PUA
> 
> 
> 
> On 10/31/2016 08:58 PM, Courtney Duncan wrote:
>> Hi Bob and Mike,
>> 
>> Yes, I plan to use this method next try.  Also, several have suggested that I should get the coldest visible place on the sky to work from, something which I hadn’t been careful enough about before.
>> 
>> I used the Alt-F data in my 10,000 second EME2 analysis for my 2006 AMSAT Symposium paper so I’m pretty familiar with the EME2 version anyway.  I may have reverse engineered it at the time.
>> 
>> I’ll look around and see if I can find that MUD paper.
>> 
>> Thanks for the help,
>> 
>> 73, Courtney, N5BF
>> 
>> 
>> 
>>> On Oct 15, 2016, at 10:47 AM, Bob Larkin <boblark at proaxis.com> wrote:
>>> 
>>> Hi Courtney,
>>> 
>>> Great to hear from you.  As for the measurements, what you are doing should be valid.  The number in the corner is the sum of the powers in the DFT bins, converted to dB after adding.
>>> 
>>> But, there is provision to do better.  In the FM mode (of all things) the s-meter reading is the average noise power in the 12 kHz bandwidth. In addition, the ALT-F3, ALT-F4 averaging also applies to this measurement, so you can adjust the averaging time from 0.6 sec on up. This is block averaging over the chosen time interval. Because of this "instrumentation" use, the s-meter changes to show the dBm power to 3 decimal places.  This is generally excessive, but might be useful. See, also,
>>> http://www.proaxis.com/%7Ekd7ts/v396/1CH1.HTM#sun_noise
>>> 
>>> The ALT-F data record in FM is different, and has several data items useful for this kind of measurement.  I can't find where we wrote that data format down.  Am I missing it?
>>> 
>>> Finally, I did a paper at the 2003 Microwave Update on Sun-Quiet Sky-Earth  noise measurements that has some comments on noise pickup.  I will see if I can get permission to post it.  It tries to summarize the general art of such measurements, and also adds info on using the three measurements to estimate both receiver noise figure and antenna gain.  I think some of that relates to what you are doing.
>>> 
>>> 73, Bob   W7PUA
>>> 
>>> 
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