Alex Pettit: Galactic Hydrogen 1.42 GHz RF Emission Radio Astronomy for $300
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- Опубліковано 3 жов 2024
- SARA Gift Shop: saragifts.org
SARA 2022 Eastern Conference
Galactic Hydrogen 1.42 GHz RF Emission Radio Astronomy for $300
Alex Pettit
SARA www.radio-astronomy.org
The $300 SARA ‘Scope in a Box' Radio Telescope System and Beyond
A beginner's introduction into receiving and processing 1.42 GHz RF emission signals from neutral hydrogen regions within the Milky Way
Alex Petit
This presentation will briefly overview the history and value of radio astronomy. It will describe the Analog RF and Digital Signal hardware components and the basic software needed to acquire, process, and display the data. Drift Scan data recording will be explained, and several upgrades will be suggested for improvements in signal amplitude and quality.
Keywords: radio astronomy, ham radio, antenna, SDR, Milky Way, hydrogen
A tour de force from Alex. Knowing him for a dozen years now, I would have expected nothing less. Well done, young ma. Rod WK4LR 😊
This is amazing 🤩😻. I can't believe what I'm watching. I love it.
Hi Alex - Excellent presentation!
Thanks.
Hey!! Thank you very much for this post!! Would you be able to share the basic settings used on SDR# that weren't shown in the video? I really appreciate the IF Average settings rundown and tutorial - I am not sure what is best for the SDR# settings such as Demodulation mode / Gain / Filter (I would assume that raw is the appropriate demodulation, of course, but please if you have any advice on the SDR# settings I would be extremely grateful!)
outstanding!
Excellent
I think that patch should be 106 mm diameter, not 103 mm. With 103 mm patch diameter, it resonate at about 1.456 GHz, not 1.420 GHz. Noticed 2 dB difference (noise background) between that two frequencies, 1.456 GHZ being 2 dB stronger. Just saying.
Tuning is also dependent on spacing of disk to back plane .w/ all adjustments critical to 1 mm ALSO, if unmounted, it is best to tune the feed to ~ 1,440 as the dish will load that to 1.420
I know nothing about SDR or radio telescopes, but I'd love to build one to find objects in space. Where can I get started? Are there tutorials?
Excellent presentation. I'm a newbie member, and I appreciate your presentation's thoroughness! One question, why didn't you use a "deeper" choke for your telescope... why did you decide on a depth of ~31mm? Was it because you simply burrowed the design and did not want to change that? I was thinking that if it was deeper, you might not capture the interference from the edges past the dish.
Hello Walter,
THANKS... Yes, I scaled the choke from the OM6AA design .. As it worked much better than the stock 1.7GHz, dipole, I accepted that as 'good' and I began refining other parts of the system. It could be a deeper choke might better reduce the interference pickup, but if the dish is too deep, it will limit the loop being able to 'see' the 1m part of the parabola and probably reduce the signal. Lots of permutations are possible.
I am now in the process of trying to better tune a loop and patch feed and compare them to the original. Dimensional adjustments of 1mm are significant as far as a VNA analysis shows, but I'm not sure they equate to actual performance changes .. TBD
One huge advantage to working with a small dish is that you can reach all the parts without a ladder, etc so
A/B comparisons can be done fairly fast .. Not So with larger configurations.
The Scope_in_a_Box system is a great learning tool . Begin Here !
Cheers, Alex
@@alexp8144 Thank you so much for your thorough reply... yes, scope in a box is the next step.
25:34 What sort of isolation were you looking for to determine if were purchasing the correct USB extender? Or was it just happenstance that you found the right one?
All Worked fine., but I went through 3 brands to find one with the least radiated RFI. AVStar seemed to be the best.
E.t.phone home!!
High Alex, I am tracking down parts and pieces to make a 1420.405 MHz radio telescope. I would like to start looking for a good mounting base that I can use on this project like the $700.00 Orion EQ-26 rated 26 lbs. Motorized Equatorial Telescope Mount and Tripod. What are you using and any cheaper suggestions. Is there a parts list? 😎 Thank you.
Hello, If you open the 1st comment ( by me ) you will find a long list of ideas.
I'm using an Un-Powered Celestron CG4 ( because I have one ). Many measurements can be made via drift scans and thus do not require a mount to be motorized. .. The CG-4 costs $400.
Alex KK4VB
@@alexp8144 Thank you so much for the quick reply.
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16:23 You're so on the 👃 nose. I'm at the stage at the moment. I'm trying to find the right questions to ask.