athornett

Does anyone know how to tell fake from real RTL SDR?

I bought my RTL SDR V3 from UK Amazon so it sounds like I was lucky not to get a fake! Andy

https://www.nooelec.com/store/sawbird-h1.html

About £100

I would like to encourage others to add their own thoughts on what SDR they use for radio astronomy and how effective they are. I am using FUNCube Pro Plus for meteor detection and RTL-SDR Blog V3 for hydrogen line observing, both of which work well. Andy

I think this little Dongle sized device has revolutionised radio astronomy for amateur. About £30, consists of SAW filter at 1420MHz and cascaded amplifier = really helps pull out the hydrogen line at 1420.405MHz. I dont have competitors' filters so can't compare to other options but invite anyone with those filters to submit comments here on how effective they are. Andy

I dont know if folks are aware of this new hydrogen tuned mesh antenna from Nooelec. Based on their 1.7GHz GOES antenna but little bigger and significantly pricier! Mt initial review: below http://astronomy.me.uk/testing-the-new-nooelec-1420mhz-mesh-antenna-4-11-23 I have successfully detected hydrogen with it. Andy

I am hoping to successfully attempt to get interferometry fringes at the wavelength of hydrogen once I have completed my current mapping project. I have found this little board that uses the A8302 amplitude phase comparator chip and hope I can use this. http://astronomy.me.uk/a8302-amplitude-comparator-board Andy

I have started my map of Milky Way spiral arms st 1420.405Mhz. Only very limited data points so fsr but kooking promising! See http://astronomy.me.uk/comparing-data-obtained-so-far-with-ptarmigan-array-and-sdr-on-position-of-galactic-arms-to-milky-way-map Andy

Each dipole element is 97mm long and they are in 4 x 4 array, designed for band 3 military reception

Thanks for that explanation Robin

All above is excellent advice. As simple method, put a compact Fluorescent bulb on a stand at end of garden and aim your telescope/spectroscope at it and takes it spectra. Easily identifiable lines to put into RSPEC or whatever software you are using to calibrate the spectra at start of an evening's observing. Andy

I am hoping to also produce rotation curve like that in next month or two Andy

If you are interested in hydrogen line galactic radio astronomy and want to map the Milky Way or determine its rotation curve to demonstrate dark matter then this is easy to do - I only started recently but getting some good results see my website www.astronomy.me.uk I am using an old military array - these are very rare but many people are achieving similar results with a homemade "cantenna" which is am aerial made from an old food or paint can or piece of aluminium bent into tube or plastic tube with kitchen foil around it! The Society of Amateur Radio Astronomers in the USA have also developed the Scope in a Box concept which builds hydrogen line radio telescope for £100 or so from components you buy yourself from Amazon. Apart from hydrogen line take a look at British Astronomical Association website for information on meteor observing, Sudden Ionospheric Disturbance detection (solar flares) and then there is also the Itty Bitty Radio Telescope which is old satellite dish plus £15 satellite finder plus £5 bias tee plus power adapter = radio telescope to observe the sun. Andy

I agree- it won't make ANY difference to the views at night possibly a nuisance of you ate solar viewing (with appropriate filters) Andy

I am currently on holiday so csnt measure individual elements but they are correct for band 3 military radio in UK which covers 21cm line = I am trying to remember but I think they are around 10-11cm long each, so half the 21cm. These aerials are designed to have good reception throughout the relevant military band.

Hi Giovamni, I am currently on holiday near Naples in Castellammare and enjoying your wonderful country! You lucky person to live here! Welcome to the forum. Do tell us something about your astronomy hobby. Andy

Thanks for that. Is that still the case as this is array rather than single antenna?

That is marvellous! Thanks

Hi Zihao, Thanks for getting back to me. I am VERY excited = I have compared my data plots at different galactic longitudes with yours and there is close match for areas I have so far been able to study. Wow! I would love to go the next step and create the same plots as you have done labelled "Milky Way Structure" - I don't mind if your scripts are not perfect! Any chance you could PM me with info on how to do it? Perhaps I could help polish them up a bit, if that would help in any way? By the way, although I live in England, my wife is from Penang - so its definitely a small world and wonderful to have folks from Malaysia on this forum!! I am an associate member of the Astronomical Society of Penang, who are a wonderful group doing marvellous outreach. Andy

Gorgeous looking telescope. I am very jealous! Andy

This is just what I need to help me with my hydrogen line radio observations - particularly your atlas of plots at various galactic longitudes gives me something to compare = I am on holiday at present but as soon as I get home I will compare I have so far with yours. do you know of any more comprehensive resource that shows expected plots and graphs? also what software you use to collect data, process and plot it and then superimpose your results on galactic structure? I am currently using ezRA suite from Ted a line in SARA. thanks for posting! Andy

An update to my observations with some very nice 4 day drift scajd of Cygnus region from Lichfield UK using my ohasdd array, HNA and SDR. Also an dxample of amazing outputs that come from Ted Cline's incredible (and free) ezRA suite of python software - designed for newbies like me! http://astronomy.me.uk/four-day-drift-scan-of-milky-way-at-1420mhz-hydrogen-using-sdrtriffid-array-from-lichfield-uk

I was very excited to find this thread today. I have myself been attempting hydrogen line observations and my work with some success can be seen at http://astronomy.me.uk/category/radio-astronomy/radio-observation-in-hydrogen-line-1420mhz I am using an old 86 x 86 cm square phased military array that passes the "that looks OK on my patio" test carries out by my wife, whereas a 3m dish, however much I would like one, has been permanently banned! What amazes me is that I am successfully obtaining hydrogen line traces in spite of living in the middle of Lichfield UK 400m from a major supermarket school hospital and very busy roads. These new dongle type SNAs and SDRs have revolutionised radio astronomy bringing it within reach of everyone. One piece of software that I would highly recommend is ezRA suite written in Python by Ted Cline of SARA (Society of Amateur Radio Astonomers in USA). It is amazing free and Ted is so supportive as is whole SARA membership even if you are not a member, as I discovered! If you look at my website you can see the incredible plots it produces. It will collect analyse plot data, and then place it against galactic background of known sources and Milky Way, and work out Doppler shift and give you a basic interpretation of that shift all for few clicks of the mouse! Andy

That's just what I was looking for - thanks! Andy