4X4XM's Site Map

https://www.qsl.net/4x4xm updated: 28-December-2025
  1. ↑ Ham Radio Communications
  2. Navigation icon Simple and easy site navigation
  3. A collection of books, articles, and presentations on HF propagation
  4. Amateur radio publications: books, articles, and presentations on HF propagation
  5. Ham radio demographics
  6. Ham Radio Propagation Overview
  7. Ham Radio Range Guide: How Far Can You Talk?
  8. HF Propagation FAQ
  9. Prediction vs Forecast of HF Band Conditions
  10. Radio Books on HF Propagation
  11. Regions vs. Layers: Earth's Atmosphere and Ionosphere
  12. Search Terms for HF Radio Propagation
  13. Scientific and Technical Concepts You Should Know
    14.  
  14. Understanding HF Propagation:
    Forecast, Practice, Tutorial, Apps, Tools
    relaying dynamically online data with explanations.
    Featured by The DXZone.com
  15. Understanding HF Propagation - The latest static page
  16. Understanding HF Propagation - About
  17. Multilanguage: multilingual presentation
  18. Hebrew: התפשטות גלי רדיו בתחום ת"ג
  19. Webmaster: Doron, 4X4XM - Personal Bio
Propagation
  1. A comparison between Radio and Light propagation phenomena
  2. A Quick Guide to HF Propagation Using Solar Indices
  3. An introduction to HF propagation
  4. Amateur Radio Propagation Today
  5. Band Conditions
  6. Beginner's guide to HF radio propagation
  7. ChatGPT Compares forecasting tools for radio amateurs
  8. Compare DR2W propagation tool with VOACAP
  9. Current ham band conditions
  10. Current Ham Band Conditions Explained
  11. Current ham band propagation
  12. Current ham band propagation conditions
  13. Current ham radio conditions
  14. Current Hambands Conditions
  15. Current Ham Radio Condition Charts
  16. Current Ham Radio Propagation Charts
  17. Current Ham Radio Propagation Conditions
  18. Current HF Bands Conditions
  19. Current HF Propagation Conditions
  20. Current HF Propagation Map
  21. Current Propagation
  22. DX Band Conditions
  23. DX Conditions
  24. DX conditions today
  25. DX conditions now
  26. DX ham band conditions
  27. DX Propagation Online Map
  28. DX Propagation Prediction / Real-time HF Propagation Prediction
  29. Forecast ham band conditions
  30. Forecast short wave propagation conditions
  31. Forecasting propagation - tools for radio amateurs
  32. Ham Band Conditions | Ham band conditions
  33. Ham band map
  34. Ham condition chart
  35. Ham conditions
  36. Ham propagation
  37. Ham radio condition
  38. Ham radio condition map
  39. Ham Radio HF Propagation Real-time
  40. Ham Radio Propagation
  41. Ham Radio Propagation Charts
  42. Ham Radio Propagation Forecast
  43. Ham Radio Propagation map
  44. Ham Radio Propagation Now
  45. Ham Radio Propagation: Solar Conditions
  46. Ham radio QSO planner
  47. Ham radio secrets
  48. Ham Radio YouTube Channels skywave propagation
  49. Ham Solar
  50. Ham solar conditions
  51. HF bands allocated for radio amateurs and their characteristics
  52. HF bands open now
  53. HF Propagation
  54. HF Propagation App
  55. HF Radio Propagation Basics
  56. HF Propagation Calculator
  57. HF Propagation Chart
  58. HF Propagation Condition Map
  59. HF Propagation Conditions - Global and Regional
  60. HF Propagation Expert
  61. HF Propagation Explained
  62. HF propagation for beginners
  63. HF Propagation for Newbees
  64. HF Propagation for Newbies
  65. HF propagation for radio hams
  66. HF Propagation Forecast
  67. HF Propagation Forecasting
  68. HF Propagation Modes
  69. HF Propagation Online Reports
  70. HF Propagation Overview
  71. HF propagation prediction tools
  72. HF Propagation Predictions
  73. HF Propagation Prediction Online
  74. HF Propagation Prediction Software
  75. HF Propagation Today
  76. HF Propagation Tools
  77. HF Propagation Widget
  78. HF Radio Propagation
  79. HF Radio Propagation for Radio Amateurs
  80. HF Radio Propagation Indices and Scales
  81. HF Radio Propagation Tutorials for Radio Amateurs
  82. HF Skywave Propagation For Radio Amateurs
  83. HF Radio Propagation Today
  84. The History of HF Propagation Models 1900s-2025
  85. Importance of HF Frequency Management
  86. Index of terms related to HF radio propagation
  87. Indicators of HF propagation and space weather
  88. Ionosphere Radio Wave Propagation (Skywaves)
  89. Ionospheric regional conditions
  90. Line of sight propagation
  91. Live solar events and past solar activity
  92. Mystery in wave propagation conditions
  93. NET vs. IRI ionospheric models
  94. Propagation conditions
  95. Propagation conditions for DX
  96. Propagation forecast
  97. Propagation indices
  98. Propagation of high frequency radio waves | The rebirth of HF
  99. Propagation of Short Radio Waves
  100. Propagation report
  101. Radio communication and the ionosphere
  102. Radio communication and the ionosphere
  103. Radio Communication Circuit
  104. Radio propagation charts
  105. Radio Propagation Forecast
  106. Radio Wave Propagation Forecasting
  107. Real-time DX Reports * HF Propagation Prediction
  108. Real-time HF Propagation Reports
  109. Real-time propagation conditions
  110. Real-time propagation map
  111. Real-time radio propagation map
  112. Real-time Radio Propagation Reports
  113. Real-time reports of HF propagation
  114. Real-time reports of radio propagation
  115. Radio wave propagation today
  116. Real-time HF propagation charts
  117. Real-time reports of space weather
  118. Real-time space weather reports
  119. Shortwave Propagation
  120. Skywave concept
  121. Solar Activity & Ham Radio Propagation
  122. Solar Conditions & Ham Radio Propagation
  123. Solar Cycle Ham Radio
  124. Solar Flux Today
  125. Solar propagation
  126. Solar Storms Ham Radio
  127. Space wave propagation
  128. Space Weather Nowcast Serge Y. Stroobandt, ON4AA
  129. Space Weather Predictions
  130. Skywave Propagation for Radio Amateurs
  131. Skywave Propagation Today
  132. The mystery of HF propagation
  133. The Rebirth of Shortwave Radio Communication
  134. The Solar Flux Today
  135. Tools for Forecasting and Predicting HF Propagation Conditions for Radio Amateurs
  136. Types of radio wave propagation
  137. Understanding CF vs MUF
  138. Understanding Band Conditions Banners
  139. understanding hf radio
  140. Understanding HF Radio Propagation
  141. Understanding LUF and MUF
  142. Understanding Skywave Propagation
  143. Weather influence on HF radio propagation
FAQ
  1. At what Kp index can I see aurora?
  2. Can HF Radio Propagation be predicted?
  3. How are current band conditions?
  4. How Can We Forecast HF Propagation Conditions?
  5. How do HF propagation indices correlate with solar activity, geomagnetic activity, and space weather?
  6. How do I find out what bands are open?
  7. How do radio waves propagate?
  8. How do solar flares cause geomagnetic storms?
  9. How do the seasons affect HF radio propagation?
  10. How does space weather affect ham radio?
  11. How does the ionosphere affect HF Radio Propagation?
  12. How long does it take for Solar Wind to reach earth?
  13. How to determine if a band is open?
  14. How to read propagation charts?
  15. What are band conditions banners?
  16. What are DX clusters?
  17. What are electromagnetic waves?
  18. What are Geomagnetic Disturbances?
  19. What are Geomagnetic Storms?
  20. What are HF band conditions?
  21. What are ham band conditions?
  22. What are ionospheric clouds?
  23. What are ionospheric conditions?
  24. What are ionospheric storms?
  25. What are propagation indices?
  26. What are Radio Blackouts?
  27. What are Radio Waves?
  28. What are Solar Flares?
  29. What are Solar Storms? How they induce Geomagnetic Storms?
  30. What are sprites in Earth's atmosphere?
  31. What are Sunspots?
  32. What are the forecasting tools for HF radio propagation?
  33. What are the modes of HF Radio Propagation?
  34. What are the most common modes of HF Radio Propagation?
  35. What are the Solar Indices?
  36. What causes geomagnetic storms?
  37. What causes HF propagation?
  38. What causes ionospheric ionization?
  39. What factors influence HF Radio Propagation?
  40. What is Geomagnetic Activity?
  41. What is a geomagnetic disturbance?
  42. What is a Geomagnetic Storm?
  43. What is Earth magnetosphere?
  44. What is grayline propagation?
  45. What is ham radio communications?
  46. What is Ham Radio Propagation?
  47. What is HF Propagation
  48. What is HF Radio Propagation?
  49. What is HF Radio Propagation Prediction?
  50. What is HF Wave Propagation?
  51. What is ionization, in the context of HF radio propagation?
  52. What is LUF?
  53. What is MUF? How to predict MUF?
  54. What is NVIS? » Real-time NVIS Propagation Map
  55. What is plasma?
  56. What is radio?
  57. What is radio propagation?
  58. What is radio spectrum?
  59. What is sky wave propagation?
  60. What is skywave propagation?
  61. What is solar activity?
  62. What is solar flux?
  63. What is solar flux index?
  64. what is solar wind?
  65. What is Space Weather?
  66. What is the current minimum usable frequency (LUF)?
  67. What is the current MUF?
  68. What are the current HF Propagation Conditions?
  69. What is the difference between geomagnetic and ionospheric storms?
  70. What is the difference between global and regional HF propgation conditions?
  71. What is the difference between solar indices and propagation indices?
  72. What is the difference between solar proton flux and solar proton density?
  73. What is the difference between the Greyline and the Solar Terminator?
  74. What is the difference between the Magnetosphere and Earth's magnetic field?
  75. What is the interplanetary magnetic field (IMF)
  76. What is the magnetic field of Earth?
  77. What is the T index?
  78. What is total electron content (TEC)?
  79. When will HF band conditions improve?
  80. When will HF propagation conditions improve?
  81. When will propagation on HF improve?
  82. Which ham band is open now?
  83. Which ham bands are open now?
  84. Why are ham bands closed?
  85. Why is geomagnetic activity important for ham radio?
  86. Why is HF used for long range communication?
A collection of books, articles, and presentations 1965-2025
  1. A Beginners Guide To Radio Propagation, Karl T. Thurber, W8FX (Popular Electronics 1998)
  2. A Primer on Space Weather - NOAA SWPC 2020
  3. A Simplified Model for HF Radio Wave Propagation for Middle East Region - Halid A. Hadi, et al.(2014)
  4. Australian Space Weather Alert System (2024)
  5. Basic Radio Wave Propagation by Nor Hadzfizah Binti Mohd Radi Faculty of Electric & Electronics Eng, Malaysia (2017)
  6. Comparing Ionospheric MUF using IRI16 Model with Mid Latitude—Ala'a A. Al-Shallal, et at., Univ of Baghdad, Iraq (2020)
  7. Correlation Between The Sunspot Numbers and Geomagnetic Parameters for The Solar Cycle 24
  8. Correlation analysis of Solar activity and Cosmic ray; J.Phys.Conf. (2017)
  9. Correlation-of-Sunspot-Numbers-and-Geomagnetic-Indices-with-Various-Climate-Change-Parameters-2024
  10. Critique of IONCAP's Reliability and Service Probability Calculations (1993)
  11. Detection-and-Localization-of-F-layer-Ionospheric-Irregularities-2022
  12. Discover the Magic of HF Radio; Norm Fusaro, W3IZ(2005)
  13. Equatorial-Spread-F_Ionospheric-dynamics-1962
  14. Geomagnetic-storm-and-equatorial-spread-F-2004
  15. HF Propagation tutorial by Bob Brown, NM7M, Ph.D. from U.C.Berkeley (2007)
  16. High Frequency Communications – An Introductory Overview - Who, What, and Why? by Bill Foose, Harris-Intersil 2012
  17. HF Propagation 2, 4Z1VC Prof Yosi "Yosi" Pinhasi (2025)
  18. HamSCI: Space Weather Operational Resources and Needs of the Amateur Radio Community (2020)
  19. Introduction to HF Propagation (Part1) by Rick Fletcher, W7YP (presented at FVARC September 16, 2025)
  20. Introduction to HF Radio Propagation Australian Gov. (2002)
  21. Introduction to HF Radio Propagation Australian Gov. (2007)
  22. Introduction to Ionospheric Modeling; Bruno Nava Presentation (2020)
  23. Ionospheric Propagation; Prof. Sean Victor Hum (2018)
  24. Ionospheric Radio Propagation by Kenneth Davies (1965)
  25. John Ashworth Aatcliffe; 12 December 1902 - 25 October 1987
  26. Modeling the Topside Ionosphere Observations by Satellites (2003)
  27. NOAA’s Space-Based Space Weather Observations (2023) Erin Lynch and Nai-Yu Wang
  28. NVIS: Stephen C. Finch, AI0W (2008)
  29. Noji Article: Understanding the Band Conditions Banner; 2018-12-05
  30. Propagation Modes—Presentation, Ken Larson, KJ6RZ (2024)
  31. Propagation and Radio Science, KL7AJ, ARRL (2005)
  32. Radio Wave Propagation part 1 Introduction Marcel H De Canck ON5AU 2002
  33. Radio Waves and the Ionosphere G3YWX QST 1999
  34. Rebirth of HF by Paul Denisowski, Product Management Engineer (KO4LZ) Rohde & Schwarz 2020
  35. Sky Wave Propagation unknown author ch4 2010
  36. Regional and Long Distance Skywave Communications by Ken Larson KJ6RZ 2025
  37. Solar UV and X ray spectral diagnostics 2018
  38. Skywave Radio Intro Kenneth N. Larson, KJ6RZ (2025-7-11)
  39. Space weather effects on communications systems, June 2020, Mark MacAlester, CISA
  40. Stanley article of the month QST June 2021
  41. Suggested Correlation Formula between High Possible Frequency (HPF) and Optimum Maximum Usable Frequency (OPMUF) over Middle East(2012)
  42. The Big Gun's Guide to Low Band Propagation A book by Bob Brown, NM7M 2002
  43. The Little Pistol's Guide to HF Propagation by Bob Brown, NM7M, Worldradio Books (1996)
  44. The Mysteries of HF Radio-Statewide-Nets-D-Layer-Gordon-Gibby-KX4Z(2020)
  45. The New Dxers Handbook Third Edition, by Bryce K. Anderson, KL7UA, May 2021
  46. Understanding LF and HF propagation by G0KYA, G3NYK; RSGB (2010)
  47. Understanding Propagation by Paul L. Herrman, N0NBH; 11 July 2010
  48. Understanding Propagation by M. Landress, WB5ANN, April 2022
  49. Understanding Solar Indices by Ian Poole, G3YWX - QST - September 2002
Shortcasts — short podcasts
  1. Index of 4x4xm's Shortcasts
  2. Aurora Propagation MP3 Sound
  3. Backscatter Radio Propagation MP3 Sound
  4. Field-Aligned Irregularities Propagation MP3 Sound
  5. HF skywave propagation for amateur radio MP3 Sound 9 minutes
  6. HF skywave propagation for amateur radio MP4 Video 9 minutes
  7. HF skywave propagation for amateur radio Script
  8. Ionospheric Regions Solar Index Skywave Propagation MP3 Sound
  9. Meteor Scatter Radio Propagation MP3 Sound
  10. Propagation Modes Review MP3 Sound
  11. Propagation of radio waves explained MP3 Sound
  12. Propagation of radio waves summary MP3 Sound
  13. Solar activity and tools for radio hams MP4 Video 6 minutes
  14. Sporadic E Propagation MP3 Sound
  15. The fascinating world of HF skywave propagation
  16. Transequatorial Propagation MP3 Sound
  17. What Are Radio Waves? MP3 Sound
Find below audio clips in various languages (in alphabetical order):
  1. Arabic | عربي: التنبؤ بظروف الاتصال لهواة الراديو
  2. Chinese | 中国人: 预测无线电爱好者的通信条件 - 无线电波传播
  3. Dutch | Nederlands:
    Voorspelling van communicatievoorwaarden voor radioamateurs
  4. French | Français:
    Prévision des conditions de communication pour les radioamateurs
  5. German | Deutsch:
    Vorhersage der Kommunikationsbedingungen für Funkamateure
  6. Hebrew | עברית:
    חיזוי התפשטות גלי רקיע - גלים בתדר גבוה (ת"ג) - חובבי רדיו - תנאי תקשורת
  7. Hindi | हिंदी: ेडियो शौकीनों के लिए संचार स्थितियों का पूर्वानुमान लहर प्रसार
  8. Italian | italiana:
    Previsione delle condizioni di comunicazione per radioamatori
  9. Japanese | 日本語: アマチュア無線家の通信状況を予測する
  10. Korean | 한국인: 아마추어 무선 통신 조건 예측
  11. Portuguese | Português:
    Previsão de condições de comunicação para radioamadores
  12. Spanish | española:
    Predicción de las condiciones de comunicación para radioaficionados
  13. Russian | Русский:
    Прогнозирование условий связи для радиолюбителей распространение волн
Total visits since 17 August 2022.

Repeat visits counted as new after 24 hours.

Flag counter site maybe down! all time
Visits (per day) since 17-August-2022
The number of site visits increased during
ionospheric events that disrupt HF radio propagation.


Visits (per day) during the last 90 days.


Visits (per day) during the last 30 days.


Hourly visits today