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Peter Masters

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About Peter Masters

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    Nebula

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    Male
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    Astrophotography, Radio Astro (very much N00b), Computing, Linux, etc
  • Location
    Eastleigh, Hampshire, UK

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  1. Yeah it does actually cause a lot of interference, so I had moved it 5m away (using USB extension cables between it and the SDR) and I also wrapped it in tin foil (clingfilm first to ensure the tin foil didn't cause connections on the PI). I don't think that is the issue still because I'd be seeing spikes on particular frequencies.
  2. Yes, I'm none the wiser about those bumps in the output. I tried to get a reading on Saturday and it took me 4 hrs in the morning to capture the background, then I managed to get 1 reading in the afternoon, which was completely flat. This is most likely because it took so long. I'm not currently hooking SDRSharp up outside to the received, but using spyserver in the middle with a PI (as PI's are more portable to the garden and easier to waterproof!). In other words, I have a desktop PC running SDRSharp doing a TCP/IP connection over WIFI to a PI running spyserver, which has the SDR and ant
  3. Ok I think I understand a bit more about what is going on with the plugin now but I've failed to calibrate it for anything more than 1000 on the dynamic averaging. The link I had earlier (https://www.rtl-sdr.com/cheap-and-easy-hydrogen-line-radio-astronomy-with-a-rtl-sdr-wifi-parabolic-grid-dish-lna-and-sdrsharp/) suggested it would take 6-7 mins but it's still not said calibrated. Even so, I would have expected to see some variation building in the wave though?
  4. Ah ok thanks - I have to admit I wasn't quite sure what I was doing with the sliders. I shall try again and see where that gets me!
  5. Hi Jim, Yes, it definitely seems to demand a pint of blood! As a computer programmer, I'm fine with the software, but radio is a black art. I'm mostly running this on a raspberry pi as it's more portable for putting this outside (though therefore running linux), but I do have a laptop that I use for astrophotography which I have tried with SDR sharp. I'm not really trying to get a background signal yet - I guess this is equivalent to a dark or flat frame in astrophotography (effectively working on the (Signal+Noise) - (Noise) = (Just Signal) principle). In theory, whilst a calibrated
  6. Just to prove what I'm saying - I've tuned my SDR to Classic FM (100.3Mhz) whilst plugged into the horn antenna (SDR->LaNA->Horn) and I can pick it up fine (this has got to be the most dumb way to pick up Classic FM I can think of). I then unplugged the horn, and then plugged it back in again, and you can see the effect on the waterfall.
  7. Just to say that I'm also getting the same view on the waterfall with both LNAs (the SAWBird, which is filtered to 1.4Ghz and the LaNA which isn't). I can see changes from plugging in the antenna so everything looks sensible to me, but not gettin' nada
  8. Aaand back to tearing my hair out :). So apart from that one blip that I put above (which whilst "looking" like a hydrogen bump was a very short lived spike in 2 frames, so I'm not convinced), I've not seen anything come out. I've tried increasing/decreasing the various gain controls to see if that affects things. I've tried SDRsharp, but again, nothing. I've confirmed that plugging in the LNA causes signal, and that then plugging in the antenna causes additional change, which suggests that there is an end-end connection. I've also re-confirmed all the electrical connectivity on the an
  9. Well, I may have seen something. Ignore the LNA thing, the following graphs were taken with the SDR->SAWbird LNA->Antenna, and they're definitely doing something. This is a sequence of pictures taken at 2min intervals. The waterfall is a bit weird, and somewhen during my series of 30 pics (including these 4) the wind blew the antenna over - murphy's law would suggest it was right in the middle of the useful bit of course, but I didn't look at the time . Anyway, this data is promising. The calibrations are inaccurate as I haven't recaptured them but this is definitely progress. Tha
  10. Ok, @Carl Reade Thank you for the steer, and I got some interesting results. I just pulled up a live view of the SDR (web based, called OpenWebRX - useful on the PI when it's not plugged into a display directly!). So I tried pointing at the sun and away, with no discernible results. However, I then simplified my setup to just the SDR and the horn antenna (i.e. no LNA). I saw the output change! I then unplugged it, put the LNA back on - nothing. Add the antenna, nothing. I'm thinking my LNA is bust (this is the SAWbird+H1 thing). I have another LNA (the wideband LaNA one), so I
  11. Hi Jim, Thanks - keep at it, sounds like you have a similar SDR to me, I have the "Nooelec NESDR SMArt v4 SDR". As I wrote my original question, it was starting to sound like a Nooelec advert - lol, but I did like their LNA as it had the filter in it (and people had had success with it). In terms of probe, I started out with a length of brass bar. I rebuilt the connector though and decided to make something where I could easily change the probe (and I read that a thinner probe means a less broad reception which sounded useful). I've now gone with an electrical "choccy block" approach
  12. Thanks Ed, Hmm ok, I think I might have found a "smoking gun". One of the connecting wires was shorted out in the plug, which would certainly explain things. I checked everything at the aerial but hadn't checked that. I've adjusted things and I'm going to try this with just the LNA later and see what happens. I've confirmed all the connections this time, but at least the problem so far was at a level I can understand Let's see what we get later! Peter
  13. Hi Ed, Thanks for the reply! - yes this is definitely a learning curve. The number of scary scientific papers with detailed FFT algorithms that come up when you just type "radio astronomy introduction" in google is probably not a good sign! It seems quite a small community of experimenters as I keep stumbling across the same people via different routes! I have tried just the LNA (Sawbird), which I powered with Bias-Tee to simplify things, but still no joy. The Antenna is definitely conductive - I've used a multi-meter to test connectivity between the 4 sides, the end and the negat
  14. Hi All, Sorry need some help here as I think I've consumed all the stuff I can find on this, and I'm not getting anywhere. It's definitely time to call in the experts as I'm definitely not one of them! I've been trying to detect neutral hydrogen - we've all thought of this one - build a horn antenna, map the galaxy, detect the spin rate etc. I followed the design from SETI - the "Horn of Plenty" http://www.setileague.org/articles/ham/horn.pdf. I used conductive Kingspan insulation, with conductive tape. There's no separate waveguide (read: oil can, etc) - the cone just tapers. I
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