Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

stargazine_ep3_banner.thumb.jpg.5533fb830ae914798f4dbbdd2c8a5853.jpg

HN50

SID detection with UKRAA VLF radio

Recommended Posts

My attempts at SID monitoring have been languishing for a while due to radio problems, though I have been getting to grips with Arduino and even had a go at building my own.

In order to move things along I went to the UKRAA stand at Astrofest and bought the VLF radio kit, their signal generator and the 15V power supply.

Last weekend I soldered the board.  It wasn’t too difficult following their instructions which are pretty clear.  The only fiddly bit was soldering on an SMD capacitor but they also give you a through-hole one as well.  Initial tests suggest it is working but I will have a better idea when it is all connected.

0CC3CEFC-EEEE-4FAF-B25F-0671DA655413.jpeg.8367462c0e9d7937cd1689a551bba0a7.jpeg

This weekend I have been working on the housing and hopefully tomorrow get the leads soldered.  From left to right will be led power, 15V in, 15V out, antenna in, then analogue -ve and +ve (can be 5V or 2.5V).  
 

367697D8-C0E2-4F25-9A2E-C7792136DCE6.jpeg.28e2a380451497749b899f98001f7c52.jpeg

E3E79041-74A8-41F4-B9AC-129B9A40777F.jpeg.45d19089ed8d97b805a688a38a7e84a8.jpeg

I am building it as-is, so the first iteration will have the radio running off mains power and in turn the radio will power the Arduino.  That seems a bit backwards but I would just like to get logging data.  For the time being it will write to an SD card, but the Arduino MKR 1010 looks rather good and comes with WiFi and encryption.

That though, is a long way off..!  Anyway, this shows progress so far.

Edited by HN50
Space
  • Like 2

Share this post


Link to post
Share on other sites

I found a length of old extension cable so split it down into the individual wires with a view to using them in this radio.

Power in and out are wired up, as is the power LED.  Antenna BNC socket is connected too.  I had a bit of an accident with the black analogue out socket (broke it), so have ordered another and will sort next weekend.  Red one is soldered and screwed in place.

F6CF07B4-0E65-4151-A9A9-27BED1B9182C.jpeg.36f2c5a15b70503e1089342e4dc3dafc.jpeg
So after that I have just been using the multimeter to check voltages and connections, the voltage out is about 14.8V which will easily power the Arduino - the home brew one I made has a 5V switching regulator that can take up to 36V.

I had hoped to get it all done this weekend but I am pleased with progress.

Edited by HN50
Text

Share this post


Link to post
Share on other sites

It had been a bit difficult to get much time lately to finish the innards, but a bit of work today and the radio is done.

I tested the output of the 5v output with my multimeter and it is measuring 0.43/0.42V.  I don’t know if that signifies something is wrong, but I also wonder if as I don’t have an antenna plugged in there will be very little signal in anyway.

9853D320-CA7B-4C02-8E79-454FC806CFCA.jpeg.8fb9fb8c8ddb1a97e4154c5a6a549ed0.jpeg

The 12V regulator sits underneath the pencil line on the lid so I might cut several air holes.  But for the time being the radio is built.

DE301F14-FF5B-4F8F-A294-ED4CFA1E3F6E.jpeg.b4cd2945b5c126eee8811f7fb718d653.jpeg
Next I will have to try tuning it.

Share this post


Link to post
Share on other sites

It has been a bit of a while since my last post but I finally got back to doing some more work on this.

The first task has been has been to tune the radio.  I have opted for Rhauderfehn (23.4kHz) as I understand there is a maintenance window each day when it gets turned off and which helps work out if you are tuned correctly.

I worked my way through the UKRAA instructions and it wasn’t as difficult as I expected, just a bit fiddly.  The instructions say the trimmer resistors have a maximum of 15 turns, but I found mine were 30.  I mailed UKRAA about this though and they got back really quickly.

Anyway the photo below is the outcome of this.  :)

8E1E638E-D976-4903-9193-232D1D55C18F.jpeg.dba045006975a5d3ee7feaefdcc99af5.jpegIt does not look much but that 1.23V took a few hours..!  I am using the 2.5V output so there is some headroom for the signal to vary when a flare happens.

So I think the radio is tuned.  

Next was to tune the antenna.  I am going to use the one I built in another thread but have assembled my own tuning unit (inspired by the UKRAA one).

My creation isn’t a thing of beauty but it gives a range between 135pF to 4.2nF.  The dip switches allow you to increase the capacitance and there is a variable capacitor for finer tuning. 

83E9A5D3-2BB2-4A05-A4E0-F2A605E15D11.jpeg.71eccc4b913a2ba8671eb34317341d48.jpeg
The white capacitors are 1nF, the blues 0.1nF

B30B8CFC-4697-4F1B-AC67-60A8873A6F18.jpeg.9d0e5088404fdad7ddd3bd3e82a0a9dc.jpeg
B8486889-B516-4EFC-B063-7187B4409419.jpeg.bfcbfb687d8a3b7cbaf4dc2984b6cf83.jpeg
A few more things to solder but then I can get it connected to the antenna and start up the oscilloscope.  

Looks like tomorrow is taken care of!

  • Like 1

Share this post


Link to post
Share on other sites

I carried on with the antenna today for a few hours.  I found an old project box and screwed that to the antenna base and with a few wires connected up the tuner with bnc male socket.

752D5ADE-FC68-451F-83E4-5E688CF8B734.jpeg.de2e881fc7fad703a9c03aeb0c855e20.jpeg
 

72094548-ED34-4948-BD3D-0CD4D4586EF7.jpeg.92d8f3de778eed82b0cbe5f7a9a147cd.jpeg

Things were going well up to this point so I switched on the oscilloscope and started measuring.  Unfortunately the oscilloscope is 9V (JYEtech),  it worked for a while but then stopped at which point I realised the transformer was still on 12V.

So I may no longer have an oscilloscope(!).

To get round this I got out my LCR meter and measured the inductance of the antenna with tuner and extension cable added.  I then found an online resonant frequency calculator and put in 23.4kHz and it fired back 2.269nF.  I then used the LCR meter to set the tuner.  

C0600AB6-9D98-476E-90CD-8D8376AE8AA2.jpeg.2e937031227dbbedd9bcbfebe68e2d24.jpeg

I don’t know how accurate this is but I can tweak it if needs be once the antenna is connected and logging.

So the next task will be to get the Arduino measuring the output voltage from the radio.  

Share this post


Link to post
Share on other sites

Today I set about getting the Arduino to read the voltage from the radio.  I have built a home brew version from an Instructables page (YABBAS - ‘Yet Another Bare Bones Arduino on Stripboard :) ) and got it onto the breadboard.

8A643F8E-CF56-416C-A2D6-48D17C136A88.jpeg.460533100553cadefeb03526d4021642.jpeg
I have set it to run using the internal voltage reference of 1.1V and added a voltage divider to drop the maximum output from the radio down to 1.1V as well.  My thinking (happy to be proven wrong) is that at 10 bit each increment will then be equivalent to approximately 1 mV rather than 5mV if I had been using the full 5V range.

I got this working and then wired up the SD card and RTC.  

D0E43D61-184E-4978-A530-930DE55BAC9D.jpeg.a6c76153b078953efb93ddb3fdcb3ed8.jpeg
It now goes into hibernation, gets awoken by an interrupt from the clock, resets the alarm to go off in a minute’s time, takes a voltage measurement, writes this and the time to the SD card and then goes back to sleep.  Which looks like this on the serial monitor;

727AA69C-DF6C-4258-A6DC-35DCBE717BBC.jpeg.82afde7cc91dd6a0e70d222332aa9377.jpeg

Next step might be to get a veroboard circuit built for a more permanent set up.  Not least as my sausage fingers keep knocking out the jump leads.

Share this post


Link to post
Share on other sites
Posted (edited)

I did a bit more work today and built a circuit board that the Arduino plugs into.  This gets rid of all the jump leads in the breadboard and gives slightly more secure attachment of wires.

000E2BBD-D99A-49CB-9E36-B020E8A2EED3.jpeg.00916bec29025fa4c46b6fb0c7830402.jpeg
I tested it for a few hours and it does indeed run in the same manner as the breadboard circuit; I didn’t want to set it running only to find it does not work.  I don’t have a case for it yet as it is a prototype and I may need to make further changes to the circuit.

Next I set about tuning the antenna.  I wrote a sketch that shows the voltage coming out the radio every second and began adjusting the capacitance in the tuner - it gradually began to increase and I spent a while trying to find the maximum.  
373E459F-AE00-47A2-BD90-6B8330A46894.jpeg.7c56f214537e4500e836d69f8960a698.jpeg

The signal is a little noisy (!!! sounds familiar from previous VLF experiments), however from a functional point of  view the Arduino is now logging data coming out the radio.  I am going to leave it in my roof for a few days to see what gets recorded and go from there.

5CDB6262-83B1-4C52-B75B-F6D0E74F6749.jpeg.cb95416acc3b69a0d38f11929d1d317c.jpeg

Quite pleased with progress so far, not least as I have something beyond the breadboard stage!

Edited by HN50
Picture order
  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

I have had the radio logging since Monday and was interested to see what had been happening, so today I went up into the roof and pulled the data out.  To my surprise/relief it has been logging data all that time.  The overall pattern looks like;

DHO38_20200413-20200417.thumb.jpg.24238011817cd9217746eb4b9c74189e.jpg

Hmmm, seems a bit noisy but there do appear to be patterns in there and not just a load of random noise.  The plot for 14/04/2020 looks like;

DHO38_20200414.thumb.jpg.69f53c8582d91aad4beb7f2c157d4c6c.jpg

That abrupt drop in signal between 8 and 9 AM is very useful as that is the maintenance window when DHO38 gets switched off.  So that is visual confirmation I am tuned to the correct frequency.  There is a rise/dip/rise around dawn, but later in the day it all goes a bit pattern less. 

15/04/2020 and 16/04/2020 don't show the expected diurnal pattern (though I can see the maintenance interruption on 15th)

DHO38_20200415.thumb.jpg.ef75cd157ddf0d7234ab44a5daaa5a6f.jpgDHO38_20200416.thumb.jpg.58c8dbb8f4c79a60a40d37f04a08886d.jpg

Finally 17th to ~13:00.  Again it has a similar dawn profile to 14th and also shows the maintenance window.

DHO38_20200417.thumb.jpg.ec9a9199fc5466e4b2910fb7d4e82ef8.jpg

I have been in touch with UKRAA and the problem looks likes noise from appliances round the house swamping the signal from DHO38 - LED lights, computers etc.  So I have been turning stuff off at particular times to see if I can work out who the culprits are.  So my timings are;

17/04/2020

16:45 - Turned off everything upstairs at mains (LED lights/pc/phone chargers/toothbrush chargers)
17:00 - Turned off boiler for 15 minutes (not at mains)
17:15 - Unplugged my laptop for 15 minutes
17:30 - Turned on oven at 17:30
18:00 - Turned off mains alarm clock

I will then start turning stuff back on sequentially to see what happens...

Edited by HN50
Spacing

Share this post


Link to post
Share on other sites

Over the course of yesterday evening I spent time turning off and on lights, chargers, computer and so on in order to try and replicate some of the (massive) interference and strange readings I had recorded in previous days. My thinking was that I could at least identify and perhaps mitigate them, so today I went and pulled out the data to analyse.

The full day is below.  Immediately I was a baffled (can't see the affects I had hoped for) but also pleased as it is starting to look like the type of plot I would like to see, plus I can still see the null during the maintenance window.

DHO38_20200417.thumb.jpg.29ba6ff91a1c3d4d88fa34085e6d0680.jpg

I went back to my log of what I did when and plotted it onto the data.  As before I was trying to replicate some of the anomalies I had seen on the 15th and 16th, but when I look at the plot I don't really see any obvious impact.  I have not run this via any statistical analysis but certainly by eyeballing it my tests have not had the effect I had wanted.

20200417_Testing_Annotations.thumb.jpg.c7883fa0cce0cdeb44324b4342ea87d2.jpg

So... 

I have been turning things on and off again earlier in the day today in the hope that I will be able to see some impact, but I am beginning to wonder if something odd was happening to my setup on the 15th and 16th.  I am also leaving them on for longer. 

What I have pulled out for the 18th already looks similar.

DHO38_20200418.thumb.jpg.edb0038c21f0cfd05a77eff8cf31e49e.jpg

I have remembered that the RTC has an inbuilt temperature sensor so I will tweak the Arduino code.  The instructions mention that temperature can affect tuning so it won't hurt to log it anyway.

Anyway, more things to think about!

 

Share this post


Link to post
Share on other sites

 I have been looking at the UKRAA SID detector so am following your posts with interest. looking forward to the next update

  • Like 1

Share this post


Link to post
Share on other sites

I checked the data again today and compared the signal to the times I turned things on and off.  As far as I can see they had no affect on the signal which I am pleased about however as can be seen in the chart below something else appears to have happened...

20200418_Testing_Annotations.thumb.jpg.6a6b17c689645743095b5ff4fff0e459.jpg

There is a huge jump in signal after I changed the SD card that lasted for several hours.  I don't quite know what has happened there but I left the radio running, unplugged the Arduino, changed the SD card before turning the Arduino back on.  That elevated reading kicked off again later and has carried on into today;

DHO38_20200418.thumb.jpg.0eed927c0c0c6534942c21731c9c368f.jpgDHO38_20200419.thumb.jpg.482146d1be925b8b9775333bfcc16e9b.jpg

I can still see the 5 AM jump as well as the maintenance window 8-9, but the overall signal seems to be between 0.7 and 0.8 volts.  I am wondering if that jump in signal is due to the Arduino, I have been having a look around and I may need to add in a decoupling capacitor between the Arduino ground and the pin I am using for the voltage divider.  It makes me wonder if the funny readings on the 15th and 16th were also caused by this(?).

I decided to turn everything off at 11:48 for an hour or so and turned it back on at 13:15 but I am tempted to just leave it running for the week.  I am working again from tomorrow and won't have a chance to do any more today.  Next weekend I will build another veroboard chassis that the Arduino/SD reader/RTC/power leads plug in to and add a capacitor, if that works I will then retrofit the capacitor to the other board to keep them synchronized.

It also means with a second chassis I will be able to leave my production system running in the roof until I have tested changes and am ready to deploy them. 

Dear Lord, that sounds like I am back at work already..!  :D

 

Share this post


Link to post
Share on other sites
18 minutes ago, Tomatobro said:

 I have been looking at the UKRAA SID detector so am following your posts with interest. looking forward to the next update

Hi,

Thanks for reading, our posts crossed! 

Dave

Share this post


Link to post
Share on other sites

I have constructed a "SID" antenna and have been using the sound card input as a first look at recording "SIDS" but Speclab just locked up and I lost my first days data. I think there is a BMP image somewhere on the hard drive so will post it here if its recoverable.

As I understand it we are looking for a sudden drop in signal strength with a slow recovery?

 

Share this post


Link to post
Share on other sites
38 minutes ago, Tomatobro said:

I have constructed a "SID" antenna and have been using the sound card input as a first look at recording "SIDS" but Speclab just locked up and I lost my first days data. I think there is a BMP image somewhere on the hard drive so will post it here if its recoverable.

As I understand it we are looking for a sudden drop in signal strength with a slow recovery?

 

Hi,

That is annoying, have you been logging to a .csv as well? 

I think the change can be an abrupt decrease or increase, but both will be followed by a gradual recovery.

Dave

Share this post


Link to post
Share on other sites

Ran it again this morning and took a picture. I can see one of the stations turning on and off. The down trace is when I unplug the antenna.

 

IMG_20200420_132806_BURST1587385686670.jpg

Share this post


Link to post
Share on other sites
Posted (edited)
On 20/04/2020 at 19:41, Tomatobro said:

SID or Induction hob at 16:50 (UTC)?

 

Hi,

Sorry, with one thing and another this week I didn't get round to replying.  I had a look on the NOAA website the other day and took a screenshot. They didn't flag any events for the same time, so it might be some local interference.

image0.jpeg.474e451c3906a0ba943b6f158d9b4f00.jpeg

I resisted the temptation to pull the data out the SD card this last week and let the thing run continuously to see if I get any odd behaviour again.  Last night after 6 days I decided to look at the data.  The pattern for the week looks like;

DHO38_20200420_to_20200425.thumb.jpg.ef932368f4b3eb369ecdeb5eab9e268e.jpg

Which looked promising.  I looked at what happened after I had switched off the radio for an hour and restarted it on the 19th...

DHO38_20200419.thumb.jpg.652d25ec165883f0c17d28a815da9306.jpg

The high voltage readings had dropped off afterwards, so I think the restart helped.  So I conclude it is probably better to turn everything off before I switch the SD card! 

Individually the days looked like;

DHO38_20200420.thumb.jpg.73242a83c5fae089b30cdbd1027d6fd3.jpg

DHO38_20200421.thumb.jpg.82da4ec4d776a80f865a1f759c342811.jpg

DHO38_20200422.thumb.jpg.4eae88dbb9725c011235035a0d5fa622.jpg

DHO38_20200423.thumb.jpg.fa46a9ba6d87dae78b16465578d65e39.jpg

DHO38_20200424.thumb.jpg.a6cfb8545cffb614ec66faa6996cca1a.jpg

DHO38_20200425.thumb.jpg.7a17008474e7336f59493d39a3eb0996.jpg

What I am pleased about is how samey they look with a remarkably consistent daily plot.  Yes, there is some noise in the plots themselves but that does not seem to swamp the overall daily pattern. 

I had a look at the NOAA data for the same period (https://www.swpc.noaa.gov/) and it looks like there may have been an even on 23/04/2020 however it does not correspond with anything I can see in my plot for that time.  So I think if that is one I didn't detect it.  Having said that the plot puts it in the smallest 'A' class - if it it had been an 'X' class I would be more disappointed!

879013962_Weeklyplot.thumb.jpg.1967db7e1adb8fc80accd567bf70dc16.jpg

I also calculated an average daily curve for all my data as well.  The gradual accumulation of data means it is starting to look more like a normal daily plot as bad data is beginning to represent a smaller percentage of the total.

DHO38_Average_to_20200425.thumb.jpg.7376651cb7bc022e6a2249d60ae35cc5.jpg

That plot does not show much, I just like it.  For the first few days of data the average daily curve looked nuts.  :)

I am still interested to see how running it all under battery power helps so the additional chassis I build today will have space for a TIP120 transistor to act as a switch.  I also have a pack of 12 NiMH AA cells that I will solder into a single pack but that will have to be another weekend.  Likewise, I don't forever want to be writing the data to an SD card so in spare moments I have been looking at the Arduino MKR WiFi 1010.  Further down the line I would like to write data to a database (nicely dovetails with my day job!) but for the moment I want to get to grips with the basics; I have found the jump from kitchen table prototype to reliable sensor is a big one.

Today's tasks;

  • Add a decoupling capacitor to the voltage divider to see if that helps smooth things a little
  • Build second chassis that is 1:1 copy of existing one
  • Change code to log temperature measured by RTC as well

Also when I get it running again tonight I will make sure the radio and Arduino are out of the plane of the greatest sensitivity of the radio.  I don't know if that will help but it is worth a try.

Thanks for reading.

 

Edited by HN50
NOAA link added

Share this post


Link to post
Share on other sites

And this is a GIF for the week.

Weekly_GIF.thumb.gif.1713b80022cf4d462af434e7f024d575.gif

Share this post


Link to post
Share on other sites

Thanks for posting your latest data.

Its interesting that out of 5 laptops of varying vintage only one has a sound card that seems to work. My setup is based on Jeff Lashleys book the radio sky and how to observe it.  I now have Spectrum lab writing a .txt file and are doing the post analysis in a spread sheet. All the "interesting" activity seems to be at night. I have to keep in mind that the book is now some ten years old so not sure how current the transmitting stations are etc.

If I go the UKRAA receiver route I would write some software for a PIC processor and do the averaging of the data before sending it too some software called MakerPlot for graphing. Take a look at Makerplot as its great software for this kind of thing as it receives RS232 commands and plots accordingly.

Share this post


Link to post
Share on other sites
3 hours ago, Tomatobro said:

Thanks for posting your latest data.

Its interesting that out of 5 laptops of varying vintage...

Hi,

That MakerPlot looks interesting as you could hook up several Arduinos to feed in to it.  
I would like to go down the cloud route myself as I love the idea of building a sensor (battery or mains powered) that just fires its data off to an internet connection and all the processing and analysis happens online.  The Arduino store page for the MKR 1010 has links to several articles that discuss this plus it has some encryption built into the board from the outset.
 

How do you find SpectrumLab?  People seem to get good results but I found it a bit frustrating and looked at other means of detecting SIDs, which brought me to this method.

Dave

Share this post


Link to post
Share on other sites

Today’s work;

I have built a 1:1 copy of the chassis so I can undertake further development and still leave my production set up logging in the roof.  They look and work exactly the same, which is good!

1992E723-3972-4E4D-9386-631893AF6F1B.jpeg.6a80169b316e5173c3ed74cf981f1e25.jpeg

ACF9012D-7BD2-48FF-994A-3EDD428923F3.jpeg.2de7abee1ea2f720a605a4f18b482284.jpeg

On checking through my components box I found I don’t have any 10nF capacitors (might have to check again as I don’t quite believe that) however I did find some discussion about the voltage divider and if your total resistance is 10k ohms or less you don’t need a decoupling capacitor.  So I recalculated and used a 5.6k and two 2.2k ohms in series to drop to 1.1V.

9497A11A-8274-4CB9-A6B2-9D0D878D7B79.png.2e475b8a37d550be75ccf4762c676033.png

I also updated the code to log the temperature measured by the RTC.  I converted it to Kelvin as,  ummm, I could :).

It is all running again in the roof so I will leave it to see what comes back later in the week.

Thanks for reading.

Share this post


Link to post
Share on other sites
Posted (edited)

image.png.821d69a4b0d7316eb56514a26c1d0406.png

Just out of interest I measured my loop antenna response to input frequency and the peak response is at 25.596 Khz. looks like I would need an ATU if I go the UKRAA receiver route. Blue is frequency steps from 20 to 40 Khz in 1 khz increments and red is ac millivolts change rms

Update. The antenna required 600pf to bring its peak to 23.4 khz. Its now located in the quietest place I could find, Spectrum lab is sorted. I am getting the early morning maintenance cut offs so just need a SID to verify the system.

Edited by Tomatobro
update

Share this post


Link to post
Share on other sites
On 29/04/2020 at 11:21, Tomatobro said:

image.png.821d69a4b0d7316eb56514a26c1d0406.png

Just out of interest I measured my loop antenna response to input frequency and the peak response is at 25.596 Khz. looks like I would need an ATU if I go the UKRAA receiver route. Blue is frequency steps from 20 to 40 Khz in 1 khz increments and red is ac millivolts change rms

Update. The antenna required 600pf to bring its peak to 23.4 khz. Its now located in the quietest place I could find, Spectrum lab is sorted. I am getting the early morning maintenance cut offs so just need a SID to verify the system.

Hi,

Thanks for the post.  One thing I quite like about this work is that it generates data for analysis :).  Out of interest what are you using to measure your loop antenna response?  Am I right thinking you have an A/C multimeter capable of going down to milivolts?

Having tuned the antenna to 23.4kHz are you finding that the other transmitters are now attenuated or have you got SpectrumLab just logging DHO38?

Dave

Share this post


Link to post
Share on other sites

I am fortunate that I have access to an expensive fluke multimeter and a frequency generator.

I will post some screen shots later on. I think that Spectrum lab offered a range of "standard" vlf frequencies and 23.4 is the only one I am currently logging ( and noise floor level) as all the others either give no signal or are seriously affected by local interference such as our induction hob and gas boiler.

I am reasonably confident that I am recording DHO38 because rotating the antenna gives me a peak signal when pointing towards the station in Germany and I am seeing the early morning maintenance shutdown sessions. I can see a problem trying to extract small signal changes from the data as the noise span covers some 3db (at least). I am taking 1 reading every 30 seconds as a plot. Perhaps averaging over (say) 5 readings might help but I have not looked at this yet.

Hopefully my signal maintenance dips will match up with your UKRAA receiver data

Regards

 

Share this post


Link to post
Share on other sites
Posted (edited)

I was going to do some work on this yesterday however I found as the weather was unexpectedly better than I had thought it would be I spent it in the garden in the veg beds.  By that I mean I was working on them, not lying in them.

Today I worked out the bearing from my house to Rhauderfehn in Germany and it comes out at ~64 degrees, so once I start logging later I will re-orient the antenna.  At present the antenna is not in this orientation, however it does put (I think) a lot of noise from the house into the null zone.  So I am interested to see what the trade off will be - next Sunday I will pull out the data and have a look.

Earlier I cut the power and hopped into the roof to pull out the SD card.  Among other things I wanted to check was that the change to the voltage divider had not caused any problems, I don't know why that would be an issue but as I had made a hardware change I did want to confirm all is okay.

DHO38_20200426_to_20200503.jpg.5bfe95ec7f2cedd1762794d96f8f9ea9.jpg

The general trend looks okay, I can see the diurnal pattern, the daily maintenance period is there, the readings taken have have not berserk and the Arduino has been logging the temperature recorded by the RTC as well.

By day it looks like the following;

DHO38_20200427.jpg.9375974eebe72bc32419947899e6c64e.jpg

DHO38_20200428.jpg.ca3562e9c94e8c58d1ab6db0ff9d512e.jpg

DHO38_20200429.jpg.58c32494ac51223bd2ab022c688406a4.jpg

DHO38_20200430.jpg.df29649b810a912d912454b6dd17f3ac.jpg

DHO38_20200501.jpg.c7ddf6ed992dca5bae3d3074434a7fb3.jpg

DHO38_20200502.jpg.7f581a57cb784e8abab29d4b91189f22.jpg

And in GIF:

DHO38_20200426_to_20200503_animation.gif.ff3dc2812439e4960e606d809afa28c0.gif

My setup is still returning the diurnal profile.  Some funny stuff happened 02/05/2020 between 0800 and 1000 but I wonder if that was due to work at the antenna(?).  Otherwise though the numbers logged look as expected, and I am gaining confidence that my setup is stable.

I had a look at the GOES data - there was an event on 01/05/2020 at about 14:30 however I still think that this lower/mid B class is below what the radio can detect.

Weekly_GOES_Plot.thumb.JPG.36514bec9c516bfd70c10cf7400460bf.JPG

For the first time I have temperature from the RTC being logged as well (red line).  I am interested in this as the tuning guide says that temperature increases can push the radio into oscillation (page 16, #12) and my radio is up in the roof where things can get quite warm in the summer (touching 40 Celsius!).  I don't think though at this stage I have enough data to give any meaningful results so I am going to use it for reference over the coming summer.

Anyway, in all I am pleased with what has been logged this week and am thinking about what I will do next.  I would still like to have the option to run from battery with power being supplied by the Arduino and the radio being turned on when needed.  I looked around and found the ready-built MOSFET switch unit using an IRF520 transistor.  Even more useful I found a website that as well as advertising the module for sale also gives a schematic of it;

https://protosupplies.com/product/irf520-n-ch-mosfet-module/

Turns out I have all the bits.  Handy!  :D

I am increasingly aware that needing to go up the ladder to get an SD card interrupts logging and, while fine for testing, isn't really conducive to real time SID monitoring.  Earlier this week a page arrived with an Arduino MKR wifi 1010 arrived.

image0(1).jpeg.fb8089b469a1555fabdf0dca46df1c5f.jpeg

I think I will try and work on the switching and initial MKR 1010 investigations in parallel.

Thanks for reading - data is attached.

Dave

VLF_T2_20200503.TXT

Edited by HN50
Added data

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By lenscap
      My diy Onstep GoTo controller is basically an Arduino Mega 2560 with a RAMPS 1.5 shield, rated for 12V normal, 20V max & uses about 2A max.
      It is powered from a 12V car  battery. The lead has crocodile clips at the battery & connects to 5A screw terminals on the RAMPS.
      When I "power-up" by connecting the clips there is a spark at the terminal. This is expected, but does the sparking reduce the life of my electronics?
      If so is there a cheap/simple way to reduce or prevent this?
      I know I could put a switch in the lead but I assume the sparking would then happen inside the switch, making no difference.
       
    • By angryowl
      This will be a thread detailing some of the changes and additions I will be doing to my ASC/Weather Station project. This is version 2.0 as I'll be making some very big changes from the initial project and I think continuing on in the existing thread would not have made much sense.
      So, I still want to use an APS size sensor as after seeing the quality and light capturing capabilities of the now defunct Opticstar DS-616C XL camera and Meike lens I simply cannot go back to using a smaller lens/sensor combination. One thing is certain, I won't be paying £400 or potentially more for another APS astro sized camera so with that in mind I plan on heavily modifying a Nikon D50 DLSR and use the same lens. I chose the D50 primarily due to it having a CCD sensor (ICX453AQ) very close in specs to the one in the Opticstar (ICX413AQ) and the fact that I got a hold of a fully working body for £25.
      Now there's a few issues with going down the DSLR route which I plan on addressing as follows:
      The oversized camera body can be stripped down to bare essentials and fitted in the existing case with some moving of parts around Uncooled, the sensor is quite noisy so to cool it I plan on using the existing Opticstar enclosure with the TEC and hopefully get it purged with Argon to avoid dew formation. Also, since the box will need to be completely sealed to achieve this, there's simply not enough room inside for the main board to which the sensor connects to. The only way around this is using an 39pin 150mm long FPC extension which I managed to find and will be arriving shortly. This means I can have the sensor completely sealed with enough slack in the connection to place the mainboard anywhere I want. The D50 uses the NEF file extension as a "RAW" file format but it's not truly RAW and a heavy median filter is applied to all long exposure images to smooth out the noise. It works great for day to day shots, but in an application such as mine it'll most probably eliminate or severely affect my stars as most of them at the FL I'll be using the camera at will be a few pixels across and the Nikon median filter is very aggressive with such small features. The way around this is what's commonly known as Mode 3 on Nikons. Nikons have a additional Noise Reduction mode which takes the long exposure light first then straight after an equal length dark with the shutter closed, then applies the dark on the light and you get a further noise reduced image which again works very well, but not so much for AP. With mode 3 you essentially have the NR feature on and take an exposure but then immediately shut down the camera after the light has finished exposing. What this does is it causes the camera to dump a REAL RAW image onto the SD card without applying the median filter OR the Noise Reduction process. This obviously results in a much noisier image as expected, but all the stars will still be there and the image in this way can then be dark-subtracted and processed to my liking. I'll post some test shots I've taken to illustrate this. The D50 uses a hybrid shutter, both the CCD electronic shutter and mechanical shutter are used depending I think on the exposure length. If a high enough exposure is used, from what I understand, one can use exclusively the electronic shutter, but for longer exposures the shutters work in conjunction. Now I know the ICX413AQ in the Opticstar is more than capable of taking long exposures solely with its electronic shutter despite the fact that in its datasheet they recommend a mechanical shutter for proper use. So, my thinking is since the D50's sensor is similar to the ICX413AQ the only thing preventing the camera from being able to take any exposure using exclusively the electronic shutter is that its mechanical shutter is in the way and I don't think that the camera would prevent the CCD electronic global shutter itself to still open and close when required. However, this is all a theory at the moment and the only way to confirm it is to test the camera with the sensor outside when the FPC cable arrives. More on this later... In terms of capture software available, the D50 is actually very poor and I could only get digiCamControl to see and control the camera via USB. But I won't be using this as when the camera is hooked up to the PC its SD card is identified as a storage drive and the camera can be used as it would normally with the images appearing on the drive after being written to the SD! Since I'm using my VB app to process the images I would just point the app to that folder and should work. That's all I can think of for now but if and when new ones come up I'll add them here.
      Next I'll be describing some of the other changes planned.
    • By bottletopburly
      So  my birthday just past so money to splash on astro stuff , i will have my 1000D modded by juan at cheapastrophotography and also have ordered an autofocuser from deepsky dad https://deepskydad.com/autofocuser i know they can be done DIY but this is a neat package  and costs about the same as a SW autofocuser and a hitechastro focusmaster and i`m no electronic wizard and pavel seems to have a good product and works with ascom and confirmed it works with APT i will update in a few weeks time when hopefully i will have received and tried out . 
       
    • By arun289
      Hi,
      I would like to share my design of a smart barn door tracker. It is a simple to build isosceles barn door tracker with tangent error correction through a Arduino micro-controller. I have shared all the details about the tracker including the mechanical design, electrical circuit and the software source code here:
      https://barndoor.spa...ference-design/
      If you are interested in the math and other details about a barn door tracker, more details are there in the blog. Also find an online calculator which helps in calculating various parameters while designing a barn door tracker. The blog is here:
      https://barndoor.space/

       
      M46 and M47 shot with this tracker.
      135mm lens, ISO800, 15sec X 200 subs (50 minutes) exposure. Cannon 500D.

      Comments and suggestions most welcome!
      Regards,
      Arun
       
       
    • By kbrown
      Hi, 
      I've been working on a DIY fan for my 10" Skywatcher newt. My plan is to measure the ambient temperature and the mirror temperature with two separate thermistors and control the fan speed depending on the temperature difference. 
      My question is, does it make sense to use the fan if for some reason the ambient temperature is higher than the mirror? The fan is sucking the air out the tube at the moment. 


×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.