THEODNET / AMATEUR RADIO DIVISION / DOC-HAM-001
Amateur Radio Technical Reference
Revision 4.2.1 — For Educational Purposes — Not FCC Approved
CLASSIFICATION: UNCLASSIFIED
DISTRIBUTION: UNLIMITED
FOR HAM USE ONLY
▶ WARNING: THIS DOCUMENT CONTAINS TECHNICAL INFORMATION. READING MAY CAUSE UNCONTROLLABLE DESIRE TO BUY RADIOS. ◀
TABLE OF CONTENTS
1.0What Is Ham Radio (And Why Should You Care)
2.0License Classes — The Hierarchy of Nerds
3.0Technical Diagrams (Of Varying Accuracy)
4.0Frequency Bands — Where The Action Is
5.0Q Codes — Secret Language Of The Ancients
6.0Morse Code Translator (Interactive)
7.0Antenna Theory (Simplified To The Point Of Heresy)
8.0Getting Licensed — Next Steps
1.0 — WHAT IS HAM RADIO
Amateur radio, colloquially known as "ham radio," is a worldwide hobby and public service in which licensed operators use radio frequencies to communicate with other licensed operators (and sometimes satellites, the moon, and Jupiter, no joke).
Unlike CB radio (which requires no license and is used primarily for truckers and conspiracy theories), amateur radio operators must pass an examination administered by the FCC to receive a callsign. This callsign is your identity on air. It is yours forever. Guard it. Cherish it.
Hams can communicate locally (line of sight, repeaters), regionally, globally (HF propagation), and into space (satellite, EME — Earth-Moon-Earth, also called "moonbounce" because that is literally what it is).
⚠ IMPORTANT NOTE
Ham radio is not CB radio. If you call it CB radio to a ham operator, they will correct you. Possibly for a long time. They have radios. They have time. Do not do this.
2.0 — LICENSE CLASSES
🟢
TECHNICIAN CLASS
Exam Pool: 35 questions
TECH
Privileges: VHF/UHF mostly. Some HF spots. Basically FM radio with extra steps.
Effort Required: Study for a weekend
🟡
GENERAL CLASS
Exam Pool: 35 questions
GRAL
Privileges: Most HF. The real fun begins. World communication unlocked.
Effort Required: Study for a week
🔴
AMATEUR EXTRA CLASS
Exam Pool: 50 questions
XTRA
Privileges: Everything. All bands. All modes. Exclusive sub-bands. Peak ham.
Effort Required: Study for a month (or three)
Note: All three exams can technically be taken in one sitting if you studied enough and consumed appropriate amounts of coffee.
3.0 — TECHNICAL DIAGRAMS
The following diagrams are provided for educational purposes. All diagrams are drawn to scale*
*scale not guaranteed. actual components may vary. artist has never seen some of these things in person.
*scale not guaranteed. actual components may vary. artist has never seen some of these things in person.
|
===
|||
-----|||||-----
|||
|||
||| <-- guy wire (important)
/|||\
/ ||| \
/ ||| \
|||
|||
|||
/===\
/ === \
/=======\
~~~~~~~~~~~~~~~
GROUNDFIG 1.1 — Standard telephone pole. AM I SCREWED? (answer: probably)
+----------+ +----------+ +----------+
| | | | | |
| MIC |---->| MAGIC |---->| ANTENNA |
| (MOUTH) | | BOX | | (STICK) |
| | | | | |
+----------+ +----------+ +----------+
| | |
| +-----+-----+ |
| | | |
| | SMOKE? | |
| | CHECK. | |
| | | |
| +-----------+ |
| |
v v
YOU TALK SKY HEARSFIG 3.1 — Block diagram of a typical transceiver. Note: smoke indicates correct operation (jk call 911)
SPACE
___________
/ \
/ GAIN: 3dB \
/ \
| ___ ___ |
| / \ / \ |
| | MAX | MAX | |
| \___/ \___/ |
| |
\ /
\ SIDE LOBE /
\___________/
|
=== ANTENNA
|
=========
EARTHFIG 2.1 — Radiation pattern (dipole). The lobes go BRRR.
IONOSPHERE
......................................................
. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .
. ~~ SKY WAVE (the cool one) ~~~~~ .
.~ ~ .
. <-----BOUNCING----> .
......................................................
^ v
| GROUND WAVE |
[TX]----+------------------------>[RX]
STATION STATION
(YOU) (SOME GUY IN OHIO)FIG 4.1 — Radio propagation modes. Ohio is inevitable.
+--------------------------------------------------+ | THE RADIO SHACK(tm) | | | | [TRANSCEIVER] [TRANSCEIVER] [ANOTHER ONE] [WHY] | | | | [ROTATOR] [SWR METER] [TUNER] [MORE COAX] | | | | [LOGBOOK] [COFFEE CUP] [PIZZA BOX (old)] | | | | ============================================ | | || || | | || COMPUTER (logging) || | | || (also reddit) || | | ============================================ | | | | / OPERATOR / | | / (stressed)/ | |/ _________/ | +--------------------------------------------------+
FIG 5.1 — Typical ham radio shack layout. Not shown: the spouse's disapproval.
SWR METER READINGS: 1.0:1 [][][][][][] PERFECT (impossible) 1.5:1 [][][][][]. GREAT 2.0:1 [][][][].. FINE 2.5:1 [][][]... ACCEPTABLE (barely) 3.0:1 [][].... CALL AN ELMER 5.0:1 []...... IS YOUR ANTENNA PLUGGED IN 10:1 []....... ARE YOU USING COAT HANGER WIRE INFIN .......... COAX IS ON FIRE
FIG 7.1 — SWR scale with helpful annotations.
____________
| |
| PL-259 | <-- the good one
| (correct) |
|____________|
|||
____________
| |
| BNC | <-- also acceptable
| (whatever)|
|____________|
|||
____________
| |
| BANANA | <-- DO NOT
| PLUG | USE THIS
|____________|
WIRE NUTS: ABSOLUTELY NOT.FIG 6.1 — Connector selection guide. Choose wisely.
YOUR CALLSIGN BREAKDOWN:
W 3 T H D
| | | | |
| | +--+--+--- SUFFIX (assigned randomly, probably)
| |
| +------------ DISTRICT NUMBER
| (where you tested, meaningless now)
|
+--------------- PREFIX (country/region)
W = United States of AntennasFIG 8.1 — Anatomy of a callsign. W3THD is a fictional callsign for educational purposes.
4.0 — FREQUENCY BANDS
Table 4.1 — HF/VHF/UHF Amateur Bands (Selected). Not all bands listed. Not all bands interesting.
* Maximum power listed is US General/Extra class limit. Technician limits vary. Check Part 97. We are not your lawyer.
5.0 — Q CODES
Q codes were developed in 1912 for Morse code communication, allowing complex phrases to be sent quickly. They are still in heavy use today, even in voice communications, because hams are creatures of tradition.
CODEMEANINGWHEN TO USE
QTHMy location is...Telling someone where you are
QSLI acknowledge receiptConfirming a contact. Also a physical card you mail
QRMI am being interfered withMan-made interference. The bad kind
QRNI am troubled by staticNatural interference. Lightning. Also bad
QRZWho is calling me?When you don't catch the callsign
QROIncrease powerTurn it up (within legal limits, obviously)
QRPDecrease power / low power opsThe masochist mode. 5 watts to Antarctica
QSYChange frequencyMove along, nothing to see here
73Best regardsSign-off. Not a Q code but everyone thinks it is
88Love and kissesOnly use this correctly
6.0 — MORSE CODE TRANSLATOR
International Morse Code is no longer required for licensing (since 2007), but it remains the most efficient mode for weak signal communication and is deeply embedded in ham culture. Also it is just cool.
INPUT TEXT:
INTERNATIONAL MORSE REFERENCE TABLE:
A .-
B -...
C -.-.
D -..
E .
F ..-.
G --.
H ....
I ..
J .---
K -.-
L .-..
M --
N -.
O ---
P .--.
Q --.-
R .-.
S ...
T -
U ..-
V ...-
W .--
X -..-
Y -.--
Z --..
7.0 — ANTENNA THEORY (SIMPLIFIED)
An antenna is a transducer. It converts electrical signals into electromagnetic waves (transmitting) and electromagnetic waves into electrical signals (receiving). The theory behind this involves calculus, Maxwell's equations, and a certain amount of wizardry. We will skip most of this.
HALF-WAVE DIPOLE
The OG antenna. Two wires, each a quarter wavelength long, pointed in opposite directions. Simple. Works. You can make one with wire from the hardware store.
Length (ft) ≈ 468 / Freq(MHz)
▶ RECOMMENDED FOR BEGINNERS
VERTICAL ANTENNA
One quarter-wave element pointing up, ground radials pointing out. Omnidirectional in azimuth. Popular because it doesn't need a support at each end.
Length (ft) ≈ 234 / Freq(MHz)
▶ POPULAR, WORKS WELL
YAGI BEAM
Parasitic array with a driven element, reflector behind, and directors in front. Directional gain. Like a flashlight instead of a light bulb. Must point at target.
Gain ≈ 10*log10(N elements)
▶ POWERFUL, REQUIRES ROTATOR
RANDOM WIRE
Just... a wire. As long as possible. Connect to a good tuner and try things. Results vary wildly. This is the 'throw spaghetti at wall' approach.
Length: whatever fits
▶ CHAOS, BUT SOMETIMES WORKS
GOLDEN RULE OF ANTENNAS
The best antenna is the one that is actually installed, outside, as high as possible, with good coax. The worst antenna is a perfect design that exists only in EZNEC. Get the wire in the air.
8.0 — GETTING LICENSED
To transmit on amateur radio frequencies in the United States, you must hold an FCC-issued amateur radio license. This involves passing a written examination at a session administered by Volunteer Examiners (hams who volunteer to test other hams — it's a whole thing).
BASIC GETTING-STARTED CHECKLIST:
[ ] Study the Technician question pool (available for free at hamstudy.org)
[ ] Take practice exams until you consistently score 85%+
[ ] Find an exam session near you (ARRL exam search or HamStudy)
[ ] Bring valid ID and $15-20 exam fee (cash usually)
[ ] Pass the test. Get your callsign (FCC posts it within 24-48 hours)
[ ] Buy a $25 handheld radio (Baofeng UV-5R is traditional first radio)
[ ] Find a local repeater. Say your callsign. Someone will answer.
[ ] Immediately start studying for General because you will want HF
IMPORTANT RESOURCES:
• ARRL (arrl.org) — The national organization. License manual, band plans, everything.
• HamStudy (hamstudy.org) — Best free study tool. Adaptive flashcards.
• ARRL Handbook — The bible. 1000+ pages. Buy it. Keep it forever.
• Local ham clubs — Real humans who will Elmer you (mentor, in ham-speak).
• /r/amateurradio — Also good. Humans mostly.
END OF DOCUMENT
THEODNET AMATEUR RADIO DIVISION — DOC-HAM-001 REV 4.2.1
This document is provided for educational purposes. TheodNet is not responsible for:
antenna failures, coax fires, neighbor complaints, excessive radio purchases, or FCC citations.
73 de THEODNET
antenna failures, coax fires, neighbor complaints, excessive radio purchases, or FCC citations.
73 de THEODNET
THEODNET / DOC-HAM-001NOT FCC APPROVED73