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About Coto

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    Star Forming
  1. Hi all, I just published a new project on git: CygnusRFI: An open-source RFI analysis tool for Radio Telescopes & Ground Stations CygnusRFI is an easy-to-use open-source Radio Frequency Interference (RFI) analysis tool, based on Python and GNU Radio Companion (GRC) that is conveniently applicable to any radio telescope/satellite ground station working with a GRC-supported software-defined radio (SDR). In addition to data acquisition, CygnusRFI also carries out automated analysis of the recorded data, producing a series of averaged spectra covering a wide range of frequencies of interest. CygnusRFI is built for ground station operators, radio astronomers, amateur radio operators and anyone who wishes to get an idea of how "radio-quiet" their environment is, using inexpensive equipment like SDRs. You can check out CygnusRFI here: https://github.com/0xCoto/CygnusRFI As always, feedback is appreciated!
  2. I don't think I would vouch for them. Even though I've bought three of their LNAs, I wouldn't consider them again, because I've found many LNAs that are a better deal for money and are well-measured with vector network analyzers. G8FEK's graphs aren't very helpful, and doesn't provide many graphs (e.g. noise figure vs frequency & temperature and gain vs frequency & temperature etc.). Mini-circuits always offers all of these graphs. ZX60-P162LN+ and ZX60-P33ULN+ are definitely some high-quality LNAs mini-circuits offers, and there's many more. There's also the SPF5189Z-based LNAs, which are dramatically cheaper and are only slightly more noisy than G8FEK's radio astronomy LNA.
  3. Hi all, I just released VIRGO: An open-source Spectrometer for Radio Astronomy VIRGO is an easy-to-use open-source spectrometer and radiometer based on Python and GNU Radio Companion (GRC) that is conveniently applicable to any radio telescope working with a GRC-supported software-defined radio (SDR). In addition to data acquisition, VIRGO also carries out automated analysis of the recorded samples, producing an averaged spectrum, a calibrated spectrum, a dynamic spectrum (waterfall), as well as a time series (power vs time) plot. PICTOR is also based on the VIRGO spectrometer. You can download and install VIRGO here: https://github.com/0xCoto/VIRGO Feedback and criticism is welcomed and encouraged. Cheers, Apostolos
  4. @gabrielxp46 First of all, no need to create a thousand posts. If you want to add something, you can edit your post. I will start writing a PDF with information regarding building a radio telescope and share it on my radio astronomy community forum soon: https://community.pictortelescope.com/ (I just created it, so not a lot of activity to see). I am definitely more active there and receive notifications, so I would encourage you to post these sorts of questions there as I will be able to respond quicker. The feedhorn is galvanized steel, but any conductive metal will work (the more conductive it is, the better). I made my next horn antenna from aluminum (I got it custom designed by an engineering machine shop). Dimensions can be found here: https://github.com/0xCoto/PICTOR
  5. Can you explain what the link shows and how I can use the information it lists for meteor detection? Are they radar transmitters? And should I find a location that is 300-400 km away from me, find its frequency, tune to the frequency, and point my antenna to the general direction of the transmitter? EDIT: Also, how do I check which ones are active/inactive?
  6. I tried with a dipole with no luck. I could see FM stations fine, direction was OK too, I think. I haven't given it another chance since, mostly because I'm working on other things like PICTOR (https://pictortelescope.com/ - https://github.com/0xCoto/PICTOR), but I wish to try again soon. I've got an LNA, maybe that can help instead of building a directional antenna (e.g. yagi).
  7. Thanks a lot Richard! Could you give me some tips as to how I could go around the FM station method? Other than looking for a quiet frequency, what else should I be looking for? Should I be looking for stations outside the country/in the 300 km+ range, and trying to tune to their frequencies, or would I (statistically) nearly always get lucky on every quiet frequency? I'm using a simple λ/2 dipole antenna I quickly built, pointing to zenith. Should I be pointing to a lower elevation towards the horizon, and in what direction? Thanks again
  8. Hi all, I’ve been interested in meteor detection, but the problem is the GRAVES radar is too far from me (I live in Greece). I haven’t done any proper attempts, but is it possible for me to do meteor detection given my location? Does anyone know of a VHF radar transmitter near me? If there’s none, is it possible for me to get build a transmitter just for myself, or is that too impractical? Thanks! EDIT: Apparently it’s also possible with FM radio stations acting as the radar transmitters. My question is, you’re obviously tuning to a frequency between stations to avoid directly listening to the stations themselves, but why do the reflections off the ionized meteor trail not end up at the same transmitter frequency?
  9. And now PICTOR has surpassed 200+ unique users with over 1000+ observations on the archive!!
  10. PICTOR just surpassed 150 unique users with over 800 observations on the archive!
  11. My suspicion from what I read from the link I gave is that in the box there might be the pre-amplifier. I'm not 100% sure but that's my guess since there's nothing else to be there according to the block diagram given below in the page. I did a few simulations in CST Studio and found that a slightly shorter and thinner wire does the job for me (just by looking at the S-Parameter plot). Is there anything else I should look at to confirm this 50-Ohm impedance match?
  12. Hi Alan, Your concerns are exactly the reason I built PICTOR. Quoting from my previous post, PICTOR is an open-source radio telescope that allows anyone to observe the radio sky using its convenient web platform for free. The goal of this effort is to introduce students, educators, astronomers and others to the majesty of the radio sky, promoting radio astronomy education, without the need of building a large and expensive radio telescope by the user. PICTOR consists of a 1.5-meter parabolic antenna that allows anyone to make continuous and spectral (i.e. hydrogen line) drift-scan observations of the radio sky in the 1300~1700 MHz regime for free. For more information, please take a look at the Website: https://www.pictortelescope.com/, the GitHub repository: https://github.com/0xCoto/PICTOR and/or the PDF guide that includes some introductory information on radio astronomy as well as instructions on how to use the telescope: https://pictortelescope.com/Observing_the_radio_sky_with_PICTOR.pdf This way you will be able to observe the radio sky without having to really worry about lack of knowledge in the field. I will try to shorten the PDF Guide a bit (10 pages might be too much stuff to read through for most people I believe) and change a few things up a bit, but it includes some introductory radio astronomy information and instructions on how to use PICTOR (slightly un-updated but sufficient for the most part). If you don't have the time to read the whole PDF I'd suggest you at least take a look at the resources, it has two interesting short YouTube videos that should give you an idea of what radio astronomy is about. Ideally (for me) if you have something like Discord (see my signature) I'd be more than happy to help you there with absolutely anything you need (I suggest Discord because it is a more direct and efficient way of communicating in my opinion).
  13. Hi all, We're currently working on the 3D Corner Reflector antenna for pulsars. I emailed the creator of the original antenna but I haven't gotten a response in a while (maybe he's been busy). Here are my questions if anyone is able to help: 1) http://iw5bhy.altervista.org/info.php here the creator of the antenna says the monopole is 53 cm long. Why so long? Doesn't theory say that the monopole's length should be around λ/4 = 70/4 = approx. 17.5 cm? 2) Why so thick? 10mm sounds pretty thick to me... On feed designs for the hydrogen line I've seen thicknesses less than 3mm. How does this huge thickness help? 3) Also, how would I manage to solder this huge thick wire onto an N-Type connector? The N-Type connector's pin is far smaller than 10mm... 4) Does the ground side of the N-Type connector have to make electrical contact with the metal grid? Is a simple solder to one of the wires enough, or must I make sure the entire connector makes GREAT contact with the grid (i.e. put a metallic plate for the connector to sit on)? 5) Do the metal panels (each 2x2 side) have be in electric contact with each other (e.g. a wire or two touching between each panel)? 6) Does the antenna's ground need to be in contact with the Earth (at this frequency will good Earth grounding provide any reduction in static/noise)? Thanks a lot!
  14. Hi Carl, I provide an approximate location (very accurate considering the beam of the telescope) in the PDF guide. The telescope is not mounted on a motorized mount, but it’s excellent for drift scan observations! Users can submit observation requests via the /observe page and it will be automatically taken care of by the raspberry pi in the Faraday cage. Once the observation is finished, the user receives an email with the data of their observation. All of the above are mentioned in the PDF guide so perhaps further questions might be answered there as well!
  15. @Carl Reade Just made a post on the Radio Astronomy section of the forum about my radio telescope.
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