Thanks for the response Rob. Nice web page you have too -> What's in Milky Way ... Besides Us? I had been thinking that the OP project could be a great teaching aid in secondary school STEM. 73, John, WØPV
The site of the 'horn' is now called the "Green Bank Observatory". It is no longer part of the 'National Radio Astronomy Observatory'. FYI---
To increase the integration time, a tracker is required. You can build one or buy one for this small antenna.
that's easy: a good equitorial mount, as I noted above, will allow integration times up to almost 12hours at a time..... and can be reset with good accuracy for multi-day integrations.
Yes, you are correct. I've been there on/off since the mid-80s. Old habit of calling it NRAO. Just love using the 20 m telescope for extra-galactic flux measurements.
My web page has been used at both the high school and college level. I built it while working on the 3.5 cm & 2.1 cm galactic plane survey using the 13.6 m dual-frequency radio telescope.
WoW This project is totally amazing ... I always wanted to do some of this .. Very good job, regards.
The gods must have spoken to me directly on this one - I already had the exact SDR enroute from Amazon when I tripped across this article. (I also do astrophotography, and this looks like it would mount nicely on an AVX! ) My question is whether anybody knows approximately what the gain of the homebrew horn shown in this article is? (And would something circularly polarized such as a Helix yield a better result? (Sorry for my ignorance - up to now, "Microwaves" to me meant getting on the local 70cm repeater... --al WB1BQE
Al, in the fifth paragraph of the linked article cited in the OP the author Dave N2LVD stated, "An online calculator showed that a horn of those dimensions would have a respectable directional gain of 17 decibels." 73. John, WØPV PS - I momentarily stopped making QSO's in CW Sweepstakes just to answer this question
Sorry - I worded my question poorly. I was wondering how close something like that could get to the theoretical gain, given some amount of mechanical imperfection. (And in the case of my antennas, Substantial mechanical imperfections... )
When I looked for the dongle and the gizmo, I found that the link in the IEEE online article takes us to the Nooelec device that does not have a bias-T. The dongle with a bias-T provides an easy way to provide DC power to the gizmo via the gizmo output SMA connector. I posted the correct link in the comment section of the online article. https://spectrum.ieee.org/geek-life...f-the-milky-way-with-this-diy-radio-telescope I hope that this will help those who want to work on this project.