Various Technical RF Related Reference Material

The following is a compilation of various bits of information specific to the RF field and related operations


Quick Index
Frequency "breaks" of common bands
Digital mode communications and their allocated frequencies
Some common mathematical formulas for radio and antennas
Common "Q' signals and their meaning
International Phonetic alphabet
AWG Gauge conversion table
Resistor color codes chart
CW abbreviations and translations
The "RST" reporting system and how to use it

LED Resistor Calculator

Common frequency range designations

Very Low Freq. VLF3 KHz to 30 KHz Ultra High Freq. UHF300 MHz to 3000 MHz
Low Freq. LF30 KHz to 300 KHz Super High Freq. SHF3 GHz to 30 GHz
Medium Freq. MF300 KHz to 3000 KHzExtremely High Freq. EHF30 GHz to 300 GHz
High Freq. HF3 MHz to 30 MHz  Microwave300 GHz to 3000 GHz
Very High Freq. VHF30 MHz to 300 MHz   

Digital Mode Frequency Allocation

160 Meters - 80 Meters

1.838.150 PSK31 3.580.150 to 3.620 Data (RTTY, PSK31, Hellschreiber,
1.890 SSTV 3.620 to 3.635 Packet
3.845 SSTV
40 Meters - 30 Meters

7.035.150 PSK31 10.130 PSK31
7.037 Hellschreiber 10.130 to 10.140 RTTY
7.080 RTTY 10.137 Hellschreiber
7.171 SSTV 10.140 to 10.150 Packet 
20 Meters - 17 Meters

14.063.5 Hellschreiber 18.100 to 18.105 RTTY
14.070.150 PSK31 18.103 Hellschreiber
14.080 to 14.095 RTTY 18.105 to 18.110 Packet
14.100.5 to 14.112 Packet
14.230 SSTV
14.233 SSTV
15 Meters - 12 Meters

21.063 Hellschreiber 24.920 to 24.925 RTTY
21.070 to 21.100 RTTY 24.925 to 24.930 Packet
21.080.150 PSK31
21.100 to 21.110 Packet
21.340 SSTV
10 Meters - 6 Meters

28.070 to 28.150 RTTY 50.680 SSTV
28.120.150 PSK31, Hellschreiber
28.680 SSTV
28.690 SSTV
28.700 SSTV 
2 Meters

145.500 SSTV (National SSTV Simplex FM Frequency)
145.550 PSK31, Hellschreiber
145.600 Limited SSTV
145.650 Limited Digital applications

Common mathematical formulas

Convert frequency to wavelength
  • Full Wave: 984 divided by frequency in MHz equals length in feet
  • 3/4 Wave: 738 divided by frequency in MHz equals length in feet
  • 5/8 Wave: 615 divided by frequency in MHz equals length in feet
  • 1/2 Wave: 492 divided by frequency in MHz equals length in feet
  • 1/4 Wave: 246 divided by frequency in MHz equals length in feet
Common metric to standard conversion formulas
  • Inches multiplied by 25.4 equals an equivalent length in millimeters
  • Inches multiplied by 2.54 equals an equivalent length in centimeters
  • Inches multiplied by 0.0254 equals an equivalent length in meters
  • Millimeters multiplied by 0.03937 an equivalent length in inches
  • Meters multiplied by 39.37 equals an equivalent length in inches
Formula for converting meters to feet
  • Meters multiplied by 3.281 equals an equivalent length in feet
Converting feet to meters
  • Feet multiplied by 0.3048 equals an equivalent length in meters
Wavelength of transmission known, calculate the frequency
  • 300 divided by wavelength in meters equals frequency in MHz
Frequency of the transmission known, calculate the wavelength
  • In meters: 300 divided by frequency in MHz
  • In feet: 984 divided by frequency in MHz
  • In inches: 11,811 divided by frequency in MHz

"Q" Signals Explained

Q signals are used primarily in CW and RTTY. They provide an abbreviated way of asking a question or making a statement.  A "Q" signal followed by a question mark (?) asks a question.  A "Q" signal without the ? answers the question or makes the statement.  The following are "Q" signals commonly used by CW operators world wide
QRAWhat is the name of your stationQRQShall I send faster
QRGWhat's my exact frequencyQRSShall I send slower
QRHDoes my frequency varyQRTShall I stop sending
QRIHow is my tone (1-3)QRUHave you anything for me (Answer in negative)
QRKWhat is my signal intelligibility (1-5)QRVAre you ready
QRLAre you busyQRWShall I tell ______ you're calling him
QRMIs my transmission being interfered withQRXWhen will you call again
QRNAre you troubled by staticQRZWho is calling me
QROShall I increase transmitter powerQSAWhat is my signal strength (1-5)
QRPShall I decrease transmitter powerQSBAre my signals fading

International Phonetic Alphabet

The international phonetic alphabet is an agreed upon list of unique words that equal the beginning letter of its name.  The reason for this is to compensate for noisy, and weak transmissions where the use of the only the letter itself may be misinterpreted or not heard at all.  The International Telecommunications Union has chosen this alphabet for world wide use.  This alphabet is the same translation as the one used by the united states military and naval units
 A - Alfa J - Juliet S - Sierra
 B - Bravo K - Kilo T - Tango
 C - Charlie L - Lima U - Uniform
 D - Delta M - Mike V - Victor
 E - Echo N - November W - Whiskey
 F - Foxtrot O - Oscar X - X-ray
 G - Golf P - Papa Y - Yankee
 H - Hotel Q - Quebec Z - Zulu
 I - India R - Romeo 

AWG Gauge conversion table

Virtually all wire purchased inn the United States has its size represented by "gauge". Many designs are available for "home brew" antennas that use common wire for the elements. When building these antennas I have found that the tuned frequency and SWR can be affected by the size of the wire used. In the explanation of the antenna, you will usually see the wire size mentioned, but usually as a fraction or an inch or in millimeters. These following tables will help you convert common wire AWG ratings to standard and metric measurements for your projects. The American Wire Gauge (AWG) sizes may be determined by measuring the diameter of the conductor (the bare wire) with the insulation removed. Refer to the Wire gauge Diameter Table below for these dimensions
AWG Gauge IDStandard Size Diameter (Inches)AWG GaugeMetric Size Diameter (mm)
200.03196118

20

0.5

180.040303

18

0.8

160.0508214

16

1.0

140.064084

14

2.0

120.08080810

12

3.0

100.10189

10

5.0

80.128496

8

8.0

60.16202

6

13.0

50.18194

4

19.0

40.20431

2

32.0

30.22942

0

52.0

20.25763  
10.2893  
 
ColorSignificant FiguresMultiplierTolerance PercentageFailure Rate
Black01+/- 20-
Brown110+/- 11.0
Red2100+/- 20.1
Orange31,000+/- 30.01
Yellow410,000+/- 40.001
Green5100,000--
Blue61,000,000--
Violet710,000,000--
Gray8100,000,000--
White9 -Solderable
Gold-0.1+/- 5-
Silver-0.01+/- 10-
No Color- +/- 20-
 
AA -       All after
AB -       All before
ABT -     About
ADEE -   Addressee
ADR -     Address
ADS -     Address
AGN -     Again
AM -      Amplitude Modulation
ANI -      Any
ANS -     Answer
ANT -     Antenna
AS -       Stand by
AT - used for the @ sign for E-Mail Addresses
BCI -     Broadcast Interference
BCL -    Broadcast Listener
BCNU - Be seeing you
BD -      Bad
BK -     Break, Break in
BN -     All between; Been
BT -     Separation between address & text / text & signature
BTH -   Both
BTR -   Better
BTW -  By The Way
BUG -  Semi-Automatic key
BURO -Bureau
B4 -     Before

 

C -       Yes, Correct
CB -     Call Book
CBA - Call book Address
CFM -  Confirm; I confirm
CK -    Check
CKT -  Circuit
CL -     I am closing my station; Call
CLBK - Call book
CLD -  Called
CLG -  Calling
CMG - Coming
CNT -  Can't
CONDX - Conditions
CPI -   Copy
CQ -    Calling any station
CRD -  Card
CS -     Call Sign
CU -    See You
CUAGN - See You Again
CUD  - Could
CUL -  See You later
CUM - Come
CUZ -  Because
CW -   Continuous wave
DA -     Day
DE -     From, This Is
DIFF -  Difference
DLD -   Delivered
DLVD - Delivered
DN -     Down
DR -     Dear
DSW -  Russian CW abbreviation for goodbye.
DWN -  Down
DX -     Distance

EL -     Element
ES -     And
ENUF - Enough
EU -     Europe
EVE -  Evening

FB -     Fine Business, excellent
FER -   For 
FM -    Frequency Modulation: From
FONE - Phone
FQ -     Frequency
Freq -- Frequency
FWD -- Forward
GA -     Go ahead; Good Afternoon
GB -     Good bye, God Bless
GD -     Good, Good Day
GE -     Good Evening
GESS - Guess
GG -     Going
GLD -- Glad
GM -    Good morning
GN -     Good night
GND -   Ground
GP --    Ground Plane
GS -     Green Stamp
GUD -   Good
GV -     Give
GVG -  Giving
HH -     Error in sending
HI -      The telegraph laugh; High
HPE -   Hope
HQ -    Headquarters
HR -    Here; Hear, Hour
HRD -  Heard
HRS -  Hours
HRD -- Heard
HV -    Have
HVG - Having
HVY - Heavy
HW -   How, How Copy?
II  --     I Repeat
IMI -    Repeat, Say Again
INFO - Info
JA -    Japanese Station
K -       Invitation To Transmit
KLIX - Key Clicks
LID -     A poor operator
LNG -   Long
LP -     Long Path
LSN -   Listen
LTR -   Later; letter
LV -     Leave
LVG -  Leaving
LW -    Long Wire., Long Wave
MA -    Millamperes
MGR -  Manager
MI -     My

MILL - Typewiter
MILS -  Millamperes
MNI -    Many
MOM - Moment
MSG -  Message; Prefix to radiogram
MULT - Multiplier
N -       No, Negative, Incorrect, No More
N -       Nine (as in Signal Report)
NCS -  Net Control Station
ND -     Nothing Doing 
NIL -    Nothing; I have nothing for you;   Not In Log
NM -    No more
NR -     Number, Near
NW -    Now; I resume transmission
OB -    Old boy
OC -    Old chap
OK -    Correct
OM -    Old man
OP -    Operator
OPR -  Operator
OT -    Old timer; Old top
OW -   Old Woman
PBL -    Preamble
PKG -    Package
PSE -    Please
PT -      Point
PWR -   Power
PX -      Press, Prefix
R -       Received as transmitted; Are;
R -       Decimal Point 
(with numbers)
RC -     Rag chew
RCD -   Received
RCVR - Receiver
RE -     Concerning; Regarding
REF -   Refer to; Referring to; Reference
RFI -    Radio frequency interference
RIG -    Station equipment
ROTFL - Rolling on the floor laughing
RPT -   Repeat, Report
RTTY - Radio teletype
RST -   Readability, strength, tone
RX -     Receive, Receiver
SA -        Say
SASE -    Self-addressed, stamped envelope
SED -      Said
SAE -     Self-Addressed Envelope
SEZ -      Says
SGD -     Signed
SHUD -   Should
SIG -      Signature; Signal
SINE -    Operator's personal initials or nickname
SK -       Silent Key
SKED -   Schedule
SN -       Soon
SP -       Short Path
SRI -      Sorry
SS -       Sweepstakes
SSB -     Single Side Band
STN -     Station
SUM -    Some
SVC -     Service; Prefix to service message
SWL -   Short Wave Listener
T -         Zero (with numbers)
TEMP - Temperature
TEST - Testing or Contest
TFC -    Traffic
TIA -     Thanks In Advance
TMW -  Tomorrow
TKS -    Thanks
TNX -    Thanks
TR -      Transmit
T/R -     Transmit/Receive
TRBL - Trouble
TRIX -   Tricks
TRX -    Transceiver
TT -      That
TTS -    That is
TU -      Thank you
TVI -     Television interference
TX -      Transmitter; Transmit
TXT -    Text
U -        You
UFB -    Ultra Fine Business
UNLIS - Unlicensed
UR -      Your; You're
URL -    Universal Resource Locator
             Address For a Webpage
URS -    Yours










 

VERT - Vertical
VFB -    Very fine business
VFO -    Variable Frequency Oscillator
VY -      Very
W -     Watts
WA -   Word after
WATSA - What Say
WB -    Word before
WD -   Word
WDS -  Words
WID -   With
WKD -  Worked
WKG -  Working
WL -    Well; Will
WPM - Words Per Minute
WRD - Word
WRK - Work
WUD - Would
WW -  Would
WX-    Weather
XCVR -    Transceiver
XMAS -   Christmas
XMTR -    Transmitter
XTAL -     Crystal
XYL -        Wife
YF -Wife
YL -   Young lady
YR -   Year
Z - Zulu Time
30 -   I have no more to send
33 -  Fondest Regards
55 -  Best Success
73 -   Best Regards
88 -   Love and kisses
 

The "RST" reporting system

The RST System of Signal Reporting was established roughly in 1934 as a quick method of reporting Readability, Signal Strength and for CW.  For voice contacts only the "R" and "S" are used.  The "S" component is usually not the same as your S-Meter reading as most S-Meters aren't calibrated to track the RST System.  The RST is also reported on QSL Cards and must be filled in correctly.  For example a "569" report for a voice contact is invalid.  Note that many DX operations and contest stations merely report "59(9)" as a convenience to avoid having to log each of the real reports.  This is a questionable practice but a fact of DX'ing/Contesting
  • READABILITY
    1 -- Unreadable
    2 -- Barely readable, occasional words distinguishable
    3 -- Readable with considerable difficulty
    4 -- Readable with practically no difficulty
    5 -- Perfectly readable
  • SIGNAL STRENGTH
    1 -- Faint signals, barely perceptible
    2 -- Very weak signals
    3 -- Weak signals
    4 -- Fair signals
    5 -- Fairly good signals
    6 -- Good signals
    7 -- Moderately strong signals
    8 -- Strong signals
    9 -- Extremely strong signals
  • TONE
    1 -- Sixty cycle a.c. or less, very rough and broad
    2 -- Very rough a.c. , very harsh and broad
    3 -- Rough a.c. tone, rectified but not filtered
    4 -- Rough note, some trace of filtering
    5 -- Filtered rectified a.c. but strongly ripple-modulated
    6 -- Filtered tone, definite trace of ripple modulation
    7 -- Near pure tone, trace of ripple modulation
    8 -- Near perfect tone, slight trace of modulation
    9 -- Perfect tone, no trace of ripple or modulation of any kind
Infrequently used is the addition of a letter to the end of the 3 numbers.  These are: X = the signal is rock steady like a crystal controlled signal; C = the signal is chirpy as the frequency varies slightly with keying; and K = the signal has key clicks. "X" is from the early days of radio when such steady signals were rare.  Today most all signals could be given an X but it is hardly ever used.  It is helpful to report a chirpy or clicky signal by using the C or K, e.g. 579C or 579K.

It is very common to send RST reports in abbreviated form, for example 599, is sent as 5NN. "N" in place of the number "9". Also another time saver is for the zero using a long "T". "T" is sent in place of the number zero as in "POWER HR IS 3TT WATTS". There is a number code for all numbers, however, the N and T codes are the most common ones.  Also CW stations sometimes report their zones as "A4" or "A5" instead of sending "14" or "15".  1 = A, 2 = U, 3 = V, 4 = 4, 5 = E, 6 = 6, 7 = B, 8 = D, 9 = N, 0 = T

LED Resistor Step-Down Calculator

The calculator below will help you determine the series resistor needed to connect various combinations of LED's. LED voltages vary from about 1.5 to 6.5 with 2.1 volts being a close approximation for standard red, green, and orange LED's. Blue and white LED's require higher voltages with blue being about 3.5 volts and white about 4.5 volts. To find the series resistor needed, enter the total number of LED's, followed by the individual LED's required voltage, the LED's required current (usually 10 to 20 mA) and finally the supplied voltage (i.e. 6,12 volts etc.) Click the "Calculate Resistor Value" button to calculate the resistor value needed. Use a resistor rated higher than the displayed power in the box below "Series Resistor", most cases can use a 1/4 watt resistor 
Total LED's
LED Voltage
LED Current (mA)
Total Voltage
Series Resistor