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astronomy.me.uk The Website of Lichfield Radio Astronomy Observatory (LRO)

Astronomy observatory in Staffordshire, England.

astronomy.me.uk The Website of Lichfield Radio Astronomy Observatory (LRO)

Astronomy observatory in Staffordshire, England.

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Radio observation in hydrogen line (1420MHz)

When I detect hydrogen with my radio telescope, is it coming from the optically bright spiral arms or the optically dark areas between them?

Admin January 21, 2026 No Comments

Mostly from the optically dark regions between the spiral arms, not from the bright arms themselves. Here’s why that happens, and how it matches what you’re detecting. 1. What the…

Radio observation in hydrogen line (1420MHz)

1-4GHz Loop Feed fabrication (Alex Pettit)

Admin January 21, 2026 No Comments
Radio observation in hydrogen line (1420MHz)

Calculating the length of 1.4GHz Hydrogen Monopole Probe to use inside a cantenna

Admin January 21, 2026 No Comments

Posted by Alex Pettit on SARA Mailing List 18/1/2026: Typical calculation for a one quarter wavelength (1/4 WL) antenna is WL / 4 * 0.95 211 /4 * 0.95 =…

Radio observation in hydrogen line (1420MHz)

Incorrect length of boom for feed on Nooelec 1.4 GHz tuned mesh dish and feed

Admin January 21, 2026 No Comments

Following results of investigations by Alex Pettit were posted on SARA Mailing List 20/1/2026: The “Nooelec 1.4GHz” feed seems improperly designed : the Focal Point of a 1m f/D 0.35…

Radio observation in hydrogen line (1420MHz)

Wavelength observed in hydrogen line radio astronomy

Admin January 20, 2026 No Comments
Jupiter Radio Astronomy

Wavelength observed by RADIO JOVE

Admin January 20, 2026 No Comments
Radio observation in hydrogen line (1420MHz)

Wavelengths covered by Ptarmigan Triffid Dipole Array used at LRO

Admin January 20, 2026 No Comments

That helps a lot — Ptarmigan Triffid immediately explains the confusion 👍 You have not used the wrong antenna, only the wrong band name. Ptarmigan & Triffid (UK Army) The…

Radio observation in hydrogen line (1420MHz) Waveguides

Show field patterns at 1420 MHz, derive wave impedance vs frequency, explain why feed probes behave oddly near cutoff, and compare WR-650 vs WR-770 specifically for H-line work.

Admin January 19, 2026 No Comments

Excellent — I’ll go through all four, keeping it practical and tied to 1420.405 MHz H-line work with WR-650. 1. Field patterns in WR-650 at 1420 MHz For the dominant…

Radio observation in hydrogen line (1420MHz) Waveguides

Why do some websites describe WR-650 waveguides as being for frequencies higher than 1420 MHz? Give equations in ASCII format.

Admin January 19, 2026 No Comments

Short answer: because different people are talking about different operating regions of the same waveguide, and some descriptions quietly assume single-mode, low-loss, well-matched operation rather than mere propagation. Here’s the…

Radio observation in hydrogen line (1420MHz) Waveguides

Confusion between WR-65 and WR-650 rectangular waveguides

Admin January 19, 2026 No Comments

Here’s the clarification you need: ✅ WR-650 is a real, standard rectangular waveguide ❌ WR-65 is not a standard rectangular waveguide designation How the naming works So the confusion boils…

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Recent Posts

  • Data Collection Videos from LRO-H1(Ptarmigan Array) 23-24/1/2026 with use of ezColGR test GNU Radio Script
  • Dwingaloo 25m Radio Telescope (Netherlands) screenshot of live observation of Milky Way showing neutral Hydrogen line at Dopper shift 0 (1420 MHz) and also Doppler shifted spectrum (second peak to right of 1420 MHz peak)
  • If a mass shrinks to half of its size then how many times does it’s rotational velocity increase by?
  • Pulsar Timings
  • What are the Tsys, AEFF, and SEFD of 25m Dwingaloo dish?

Recent Comments

  1. Yoshiyuki Takeyasu on What is a geodesic parabolic dish?
  2. Admin on What is a geodesic parabolic dish?
  3. Yoshiyuki Takeyasu on What is a geodesic parabolic dish?
  4. Stephen Arbogast on Designing tuneable LRO aluminium stove pipe cantenna H-Line 16/1/2025
  5. Yoshiyuki Takeyasu on What is a geodesic parabolic dish?

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You missed

Uncategorized

Data Collection Videos from LRO-H1(Ptarmigan Array) 23-24/1/2026 with use of ezColGR test GNU Radio Script

Uncategorized

Dwingaloo 25m Radio Telescope (Netherlands) screenshot of live observation of Milky Way showing neutral Hydrogen line at Dopper shift 0 (1420 MHz) and also Doppler shifted spectrum (second peak to right of 1420 MHz peak)

Uncategorized

If a mass shrinks to half of its size then how many times does it’s rotational velocity increase by?

Uncategorized

Pulsar Timings

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astronomy.me.uk The Website of Lichfield Radio Astronomy Observatory (LRO)

Astronomy observatory in Staffordshire, England.

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