u/DeepSpace1420MHZ

This image created with Python with csv recorded drift scans 5/1 - 5/8/26, from Spectraview, “Hydrogen Line Radio Terrain," represents the results of drift scans performed using a radio telescope. The plot visualizes the detection of the Neutral Hydrogen Line at 1420 MHz as the Earth's rotation allows the telescope's fixed beam to sweep across a portion of the sky.
Breakdown of the Visualization
Vertical Axis (Z): This shows the Relative Hydrogen Signal (dB), indicating the intensity of the hydrogen emissions detected during the scan.
Horizontal Axis (X): Labeled as Drift Time, representing the duration over which the data was collected as the celestial objects passed through the telescope's field of view.
Depth Axis (Y): Labeled as Azimuth, which corresponds to the specific horizontal direction (between 75.00 and 77.00 in this view) the dish was pointed toward during the observation.
Color Scale: The "terrain" uses a heatmap where brighter yellow peaks represent the strongest signal intensities (reaching above 0.7 dB), while darker purple and black areas represent lower signal levels.
Technical Context
This specific data was generated using a 4.5-meter mesh dish. The prominent "mountain" in the terrain map illustrates the concentration of neutral hydrogen, from a section of the Galactic Plane (Milky Way), passing through the antenna's 34 dB gain beam. This type of 24/7 monitoring and data mapping is used to visualize the structure and density of our galaxy.

Recorded in Spectraview Plotted with Python Detected with a 4.5M radio telescope, 1420 tuned and filtered LNA, gain block and RSP1A.

#hydrogenline #radioastronomy #astronomy #radiotelescope

Scanning the Milky Way hydrogen line with drift scans. Each scan as a slice of an eventually bigger picture.

Running drift scans with 5000 plus lines of information per slice. The 1st project is 21 slices. 21 weeks. Each slice is a 2 degree advance of AZ. Will run through Python with Matplotlib and more to compare results.

Use the live stream audio and SpectraVue or another software to do your own course scans for experimenting. Will post whatever is scanned after the 21 slices.

#spiralgalaxy #space #hydrogenline #radioastronomy #radiotelescope

Nooelect V5

Nooelect XTR

SDRplay RSP1A

Nooelect LNA (gain block)

Hamgook LNA (gain block)

1420 BPF filter

DownEastMicrowave 1420 LNA

DownEastMicrowave gain block

My findings and personal experience,

The Noolect V5 for Hydrogen line work does well being set a few MHz wide. It is sensitive enough with resolution on a waterfall that doesn’t look bad. An LNA at the feed, direct feeding it from the LNA leaves it sensitive to system temperature changes, even with just moving the antenna. Fine for fixed drift scans.

The Nooelct XTR works basically the same but was a little more noisy on the noise floor and a little less sensitive during signal to noise.

The Noolect and Hamgook LNA’s are actually wide band gain blocks. The are good for making up coax loss inside near the SDR but not as actual LNA’s near antenna feeds.

The SDRplay RSP1A showed a little better visual resolution on a waterfall display. The biggest difference was that sytem temperature changes due to dish movement and other variables did not seem to affect the noise floor. More stable moving to different headings.

The SMA BPF 1420 filter was only found useful if not using DownEastMicrowave items. Using it with other LNA/(gain blocks) did reject some rfi spikes.

The biggest takeaway from all of this is if a quality LNA such as the DownEastMicrowave, tuned to 1420 MHz with a 1420 front filter is used and a wide band gain block is in the system, performs best regardless of other variables.

With a real quality LNA at the antenna feed setting the noise floor, and a wide and gain block of any brand is used in front of the SDR, the signal to noise ratio was optimal.

All SDR’s achieved the same signal to noise ration although the RSP1A looked a little better on the waterfall. I

Live 24/7 @ https://youtube.com/@backyard\_4.5m\_radio\_telescope?si=K1vEaJvn0OZ8uSKk

#radioastronomy #spiralgalaxy #space #radiotelescope #hydrogenlind