2026
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Calculating the length of 1.4GHz Hydrogen Monopole Probe to use inside a cantenna
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 =…
Incorrect length of boom for feed on Nooelec 1.4 GHz tuned mesh dish and feed
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…
Wavelengths covered by Ptarmigan Triffid Dipole Array used at LRO
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…
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.
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…
Why do some websites describe WR-650 waveguides as being for frequencies higher than 1420 MHz? Give equations in ASCII format.
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…
Confusion between WR-65 and WR-650 rectangular waveguides
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…
What does the 650 in WR650 waveguide name stand for?
WR-650 is the ideal rectangular waveguide for hydrogen line work. WR stands for Waveguide, Rectangular, and the number refers to the internal broad-wall dimension in hundredths of an inch. Specifically:…