Radio in general is a technologically advanced field, and those who have obtained their ham radio licenses
can tell you that learning some of that technology can be challenging. We've collected some links that can
help you understand both the basics behind radio and some of the in-depth engineering that goes into the
physics of radio, along with ways to improve your setup.
Hover over a word in
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Quick Links
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Just starting out in ham radio
Antennas
[general,
VHF-UHF,
HF]
Grounding and bonding
Propagation
[general,
solar,
other]
Signal transmission
[tuners,
transmission lines,
reflection,
return loss]
SWR
[education,
effects,
myths,
other]
Connection
[coax,
connectors,
wires,
loss]
Technology
Chokes, filters, baluns
Digital
Issues
[noise,
shack RF,
damage,
other]
Good-to-know
[general,
tips,
how-to,
best practices,
other]
Solar
[general,
panels,
charge controllers,
batteries,
other]
Repeater
[general,
isolation,
other]
Specialized
Electrical
[electricity,
batteries,
circuits,
electronics,
advanced,
other]
For beginners
[electronics,
electromagnetics,
RF,
other]
Tubes
[theory,
amplifiers,
other]
Presentations
Sane preparedness
Safety
[general,
medical,
other]
Advanced topics
Antennas
PhD required
Physics
[general,
electrodynamics,
other]
Other
Debunked myths
Other
[glossaries,
Hallas,
other]
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Just starting out in ham radio
Antennas
General
VHF / UHF
HF
Dipole
End-fed
Radials
Random-wire / long-wire
NVIS
Other
More
Grounding and bonding
Propagation
General
Solar
Other
How weather affects radio propagation
(it can affect the conditions, but no set answer fits all)
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Essentially, rain , snow, and fog typically affect frequencies over 2 GHz
very heavily, while affecting frequencies under 30 MHz very little
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On the other hand, lightning is the single largest contributor to
atmospheric noise
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Furthermore, temperature inversions can result in tropospheric ducting,
which typically affect frequencies greater than 90 MHz
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Signal transmission
Tuners
Transmission lines
Reflection
Reflections III
(Walter Maxwell W2DU, Third Edition) [PDF]
and a
link on my website to his book
and
some reviews
Page 1-2 : All power reflected from the feed line-to-antenna mismatch is conserved, not dissipated
Page 1-5 : Reflected power is not dissipated in the transmitter
Page 1-9 : A tuner allows for greater bandwidth for a given antenna
Page 7-3 : Why match at the feed line input?
Page 7-3 : A transmitter can be damaged by overloading or underloading
Page 13-3 : The antenna tuner really does tune the antenna to resonance
Page 17-1 : A tuner changes the antenna impedance by conjugate matching
Page 17-2 : Feed line length does not matter if using a tuner
Page 17-3 : The logical place for a tuner is at the operating desk, not at the antenna
The myth of reflected power
(excellent General-level article, including the math, by Davide Achilli, IZ2UUF)
The myth of high SWR causing feed line radiation
(excellent General-level article, including the math, by Davide Achilli, IZ2UUF)
Conjugate match myths
(Steve Stearns, K6OIK, 10-16-2011) [PDF]
Reflected power will NOT damage your radio
and
his original page
(good reading, but sloppily written, by Steve Ward, WC7I)
SWR and reflection
(Darrin Walraven K5DVW, QST 11-2006)
Return loss
SWR
Information on SWR can be categorized under antennas, transmission lines, and reflections, among
other things, but is a topic often singled out for discussion, and so deserves its own section
Education
Effects
Myths
Other
Connection
Coaxial cable
Connectors
Wires
Loss
Technology
Chokes, filters, baluns
Digital
Issues
Noise
Shack RF
Damage
Other
Good-to-know
General
Tips
How-to
Best practices
Other
FT8 on 10 meters, on a budget
(Tom Costello KD9CPB)
Signal attenuation due to vegetation
(graph photo from ITU)
2-meter example through a leafy, 22-foot diameter tree:
At 146 MHz, attenuation for a vertical antenna is about 6 × 10-2 dB/m, or
−0.06 dB/m = 1 − 10-0.006 = 0.0137 attenuation/m = 1.37 % att/m
For a 7 m diameter tree with thick leafage : 7 m × 1.37 % att/m = 9.6 % att
5-watt HT : 4.5 watts get through / 20-watt mobile : 18.1 watts get through
Solar
General
Panels
Charge controllers
Batteries
Other
Repeater
Specialized
Electrical
Electricity
Batteries
Circuits
Electronics
Advanced
Other
For beginners
Electronics
Electromagnetics
RF
Other
Tubes
Presentations
Sane preparedness
Safety
Advanced topics
Antennas
PhD required
Physics
General
Electrodynamics
Other
Other
Debunked myths
Folded dipole myths
(Tom Rauch W8JI)
Busting old myths surrounding end-fed half-wave antennas
(they do work : by Peter Waters G3OJV)[YouTube 13:10]
The Myth of RF Ground
(Ward Silver, NØAX, QST, 01-2015)
The myth of reflected power
(excellent General-level article, including the math, by Davide Achilli, IZ2UUF)
Coaxial cable length does not change antenna SWR
(by Gordon Hudson, AD5GG)
My feedline Tunes My Antenna!
(03-1956, by Byron Goodman, W1DX)
He also mentions that SWR will not change with transmission line length
Collection of busted myths
(ARRL, Terry Graves, K7FE, 2009)
SWR myths and mysteries
[PDF] (Andrew Barron, ZL3DW, 09-2012)
Modern batteries are safe to store on concrete
Other
Ham radio glossaries
Joel Hallas articles in QST
Other
General atmospheric opacity chart
Questions? Ask
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