Jason Burnfield’s list with sample and expected spectra. https://www.astronomy.me.uk/wp-content/uploads/2026/07/Jason-Burnfield-Nearest-Bright-HI-Galaxies-Brightness-Order-170726.pdf Post navigation What can amateur radio astronomers potentially “see” when using radio to observe the Bubble Nebula? How could a 9KHz-8GHz RF Digital Step Attenuator be used to reduce the gain on a test signal at 1420 Mhz being produced by a NanoVNA, and used to test a hydrogen line radio telescope? Currently the test signal overloads the SAWBird on the radio telescope.
