This video provides a technical introduction to both common and uncommon propagation modes at VHF.
Timeline:
00:00 Introduction
00:12 Presentation overview
00:44 About VHF
01:49 VHF versus HF
03:07 Why study VHF propagation?
04:12 About “line of sight”
05:02 Common VHF propagation modes
05:41 About refraction
06:28 Refractive index (N)
07:32 Tropospheric refraction and the radio horizon
08:34 About reflections
09:47 Extending range using reflections
10:31 Reflections and multipath
11:36 About diffraction
12:25 About scattering
13:19 About uncommon VHF propagation modes
14:34 Uncommon VHF propagation modes
14:51 About temperature inversions
15:33 About tropospheric ducting
16:19 Ducts and frequency
16:59 Ducting and weather
17:39 Two types of tropospheric ducts
17:54 Surface ducts
18:34 Elevated ducts
19:06 Propagation along ducts
19:32 Sporadic E
19:41 Ionospheric propagation (skywave)
20:26 Ionospheric propagation (skywave) – E layer
20:41 About Sporadic E (Es)
21:54 Mapping Es
22:28 Causes of Es and predicting Es
23:28 Es or tropospheric ducting?
24:05 Meteor burst
24:13 About meteor burst
24:57 Meteor size / velocity and ionization
25:43 Types of meteors
26:04 Shower meteors
26:54 Sporadic meteors and time of year
27:24 Sporadic meteors and time of day
28:22 Applications of meteor burst
29:34 Meteor burst: distances and frequencies
30:46 EME
30:44 The moon as a reflector
31:52 Advantages of EME
32:49 EME challenges
33:20 EME path loss
34:00 EME antennas
34:37 EME and noise
35:34 Position of the moon
36:50 Motion of the moon
38:02 Surface of the moon
39:06 EME and the ionosphere
40:02 Summary of uncommon VHF propagation modes
41:51 The (future) role of uncommon VHF propagation modes
43:07 Summary