In this video I dive into 20-metre band (and above) and why it behaves so differently to 40m. We recap the D-layer “sponge,” explore how the F-layer splits into F1 and F2 under sunlight, and talk about take-off angles, hop lengths and long-haul DX. With graphs, a few invented words like “jigglification,” and plenty of plain English, this is a look into how 20 m propagation really works — and why it can be both magical and maddening at the same time!
(Warning: contains maths, PDFs, and raw data files. Proceed only if heavily caffeinated.)
📚 ARRL Antenna Book – Supplemental Files (23rd Edition)
https://www.arrl.org/arrl-antenna-book-23rd-edition-supplemental-files
📄 Installation Summary (PDF) – explains where the HFTA statistical elevation-angle files live
https://www.arrl.org/files/file/Antenna%20Book%20Supplemental%20Files/23rd%20Edition/Antenna%20Book%20-%2023rd%20Edition%20-%20CD-ROM%20Installation%20Summary.pdf
📊 HFTA Documentation (PDF) – dense but explains how to interpret the elevation-angle distributions
https://www.arrl.org/files/file/Antenna%20Book%20Supplemental%20Files/23rd%20Edition/HFTA.pdf
🌐 VOACAP Online (Point-to-Point Propagation) – generate your own AoA tables and predictions
http://www.voacap.com/p2p/
📚 VOACAP Technical Docs – everything you never wanted to know
http://www.voacap.com/documents.html
📰 QEX (Siwiak, May–Jun 2011) – statistical elevation angles across HF; 50% below 6°, 90% below 16°
https://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2011/QEX_5_11_Siwiak.pdf
00:00 Intro
00:20 Recap on D Layer
00:40 The F Layer
02:06 Take-Off Angles
03:07 Long Haul DX
06:39 Take-Off Angle Chart
09:03 What happens at night?
10:26 WSPR
11:49 Why Oceans Assist
12:19 Long Path to VK / ZL
13:31 When F1 and F2 Combine
15:23 Wrap-Up Conclusion