SIGNAL METERS

It is often accepted that the "S9" point represents a received signal of 50µV (microvolts), although some equipment may specify that S9 should be calibrated at 100µV which muddies the water a little.

Convention often states that each "S" point below S9 this represents a gradation of 6dB (decibels), though this is a contentious statement as some would argue that gradations of 5 dB or 4 dB might be more typical in 'real world' S meters. S meters cannot therefore be wholly relied upon for laboratory standard accuracy and in reality merely provide comparative values.

Above is a table that shows what the actual received voltage would be on a perfectly calibrated Signal Meter using with S9 representing 50uV and the often accepted 6 dB per "S" unit calibration and comparing this with the 5dB and 4dB per "S" unit calibration. While these are not laboratory grade specifications it can be helpful to use a table such as this to provide an idea of the RF voltages being received.

As a very rough rule of thumb a receiver may require about 0.5 uV (microvolts) of RF input to produce a signal to noise ratio (S/N) of around of 20 dB.

+ 3dB  =  2 x the power or 1.4 times the voltage - about 1/2 an "S" point
+ 6dB  =  4 x the power or 2 x the voltage or approximately 1 "S" point
+ 9dB  =  8 x the power or 3 x the voltage
+10dB = 10 x the power or 3.162 x the voltage or approximately 1.5 "S" points
+20dB = 100 x the power or 10 x the voltage or approximately 3 "S" points

DECIBELS:

The decibel is not a measure of a particular electrical unit and therefore figures that are expressed as a decibel are completely meaningless unless they are related to a particular reference. A decibel is actually one tenth of a Bel and is derived from the logarithmic ratio of two voltages or current or power levels: One of these levels must be measured to act as the reference point in order that the other level (or levels) can be expressed as dB relative to that point.

So; Decibels (dBs) represent a RATIO of one voltage to another, or one power to another at the same impedance. Decibels can be either a positive figure representing gain or a negative figure representing a loss.

dBW = 10 x log of Watts

Watts =  antilog of (dBW ÷ 10)

dBV = 20 x log of Volts

Volts = antilog of (dBV ÷ 20)


Here is a table of decibel relationships:


dBs are added to represent the total gain or the total loss, while the gain or losses that are expressed as fractions must be multiplied.

e.g. a power gain of 2.5 dB is dealt with thus: 2.0 dB plus 0.5 dB i.e. 1.585 X 1.122 =  1.778


Examples:

+ 3dB  =  2 x the power (or twice the loss, for example when dealing with feeder losses) or 1.4 times the voltage
+ 6dB  =  4 x the power or 2 x the voltage or approximately 1 "S" point
+ 9dB  =  8 x the power or 3 x the voltage
+10dB = 10 x the power or 3.162 x the voltage or just over 1.5 "S" points
+20dB = 100 x the power or 10 x the voltage or just over 3 "S" points

Transmitter Power

Transmitter power is often expressed in Watts, but in amateur radio it is common to find transmitter power expressed in dBW. This is the power in decibels relative to one Watt.

e.g. if a transmitter is quoted as having an output of 6dBW then that would be the same as saying that the power is 4 watts. If a transmitter is quoted as having a power of 14 dBW the 10dBW figure (i.e. 10 watts) is multiplied by the 4dBW figure (i.e. 2.5 watts):  10W x 2.5 =  25 Watts.

Here is a table showing the conversion between dBW and Watts:

COAXIAL & OTHER FEEDER CABLE LOSSES COMPARED

When using an antenna at its resonant frequency  the VSWR should be very low and losses at HF should also be very small. However when it is anticipated that an HF antenna will be used for wideband, non resonant, operation (e.g. a popular all band 'Doublet') the VSWR could be significantly higher and losses in coaxial cable will be higher  than with a resonant aerial.

e.g. at 28 MHz when using an antenna with an SWR of 9:1 it may be perfectly possible to match the antenna system to the transmitter using an Antenna Matching Unit ("ATU"), but if using a 20 metre length of RG58 coaxial cable the losses could be around 3 dB - in which case 100 watts of transmitter power would only result at 50 watts reaching the antenna terminals.

Alternatively if Twin Feeder is used to feed an antenna such as an All Band Doublet where high VSWR will be expected the loss at an SWR of 9:1 would only be about 0.3 dB which would equate to over 90 watts reaching the antenna terminals!

	With an SWR of 1:1 at antenna  Losses in dB per 100 metres at various frequencies Cable Type: 3.5 MHz 10 MHz 30 MHz 50 MHz 144 MHz 432 MHz RG58 2.5 4.3 7.7 10 17 32 RG8 Mini / RG8-X 1.7 2.9 5.4 7.1 13.2 26.5 RG8 1.06 1.8 3.2 4.2 7.6 9.1 RG213 1.1 2.0 3.5 4.7 8.4 15 Ecoflex 10 ! 1.2 ! 2.8 4.9 8.9 Westflex 103 0.6 0.9 1.7 2.7 4.5 7.5 450 Ohm Twin 0.17 0.29 0.51 0.67
	With an SWR of 3:1 at the antenna  Losses in dB per 100 metres at various frequencies Cable Type: 3.5 MHz 10 MHz 30 MHz 50 MHz 144 MHz 432 MHz RG58 3.4 5.5 8.9 11.3 19.1 34.3 RG8 Mini / RG8-X 2.4 3.9 6.6 8.4 14.5 27.7 RG8 1.6 2.6 4.2 5.4 8.8 15.7 RG213 1.7 2.8 4.6 5.8 9.7 17 Ecoflex 10 ! ! ! ! ! ! Westflex 103* 1 1.5 2.5 3 5 9 450 Ohm Twin 0.28 0.47 0.8 1.03
	With an SWR of 6:1 at antenna Losses in dB per 100 metres at various frequencies Cable Type: 3.5 MHz 10 MHz 30 MHz 50 MHz 144 MHz 432 MHz RG58 4.9 7.1 10.7 13.1 20.9 36.1 RG8 Mini / RG8-X 3.7 5.5 8.3 10.1 16.4 29.5 RG8 2.5 3.8 5.8 7 10.7 17.5 RG213 2.8 4.2 6.3 7.6 11.5 19 Ecoflex 10 ! ! ! ! ! ! Westflex 103* 1.6 2.2 3.2 4 6 10 450 Ohm Twin 0.49 0.82 1.37 1.73
	With an SWR of 9:1 at the antenna Losses in dB per 100 metres at various frequencies Cable Type: 3.5 MHz 10 MHz 30 MHz 50 MHz 144 MHz 432 MHz RG58 6 8.4 12.1 14.5 22 37.5 RG8 Mini / RG8-X 4.7 6.6 9.6 11.5 17.1 30.1 RG8 3.3 4.9 7 8.3 11.9 18.9 RG213 3.6 5.2 7.5 8.8 12.8 20.4 Ecoflex 10 ! ! ! ! ! ! Westflex 103* 2 2.6 3.8 4.5 6.5 10.5 450 Ohm Twin 0.71 1.16 1.88 2.34

Losses are given a dB per 100 metres. For other lengths divide dB loss figure by 100 and multiply by the actual length in metres.

These loss figures are for the cable only without connectors and do not take into account termination and other losses.


ECOFLEX 10

 ! = I do not have full data for the ECOFLEX 10, but it is included here due to its attractive physical properties: The big plus for these cables is they are extremely flexible - whereas W-103 is easy to damage with repeated movement such as with a rotator or /p use with portable masts etc, Ecoflex 10, it is claimed, should be much more resilient and therefore long lasting due to its flexibility.  More information from  http://www.diodecomms.co.uk
Download the Ecoflex Product Brochure in PDF format here 

Information compiled from various sources. References:

http://www.ocarc.ca/coax.htm

http://www.timesmicrowave.com/cgi-bin/calculate.pl

http://www.kc7hxc.us

http://whwestlake.110mb.com/

http://www.diodecomms.co.uk

RG58 CQ125; RG8X Belden 9258; RG8 Belden 8237; RG213 Belden 8267
* Westflex103 unconfirmed estimated loss at higher SWR's





TRIMMING AERIALS

Antenna Trimming Chart

This following information below could be very useful indeed when constructing aerials and is compiled by DX Zone / Radio Works from the web page at: http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=13444


Use this chart as an aid in trimming the length of your antenna. It gives you an idea of the change in wire length needed to move antenna resonance a specific number of KHz.

    * Dimensions are for each leg of a half-wave dipole
    * For quarter-wave antennas (i.e. verticals ) use the dimensions directly from this chart
    * Full-wavelength antennas (loops) - multiply the chart dimensions by four (4) and change the overall length of the antenna by that amount.

Lengths are estimates. Many factors will affect their exact value.

To move	80/75 m	40 m	20 m	15 m	10 m
-500 kHz	+8' 4"	+2'	+8"	+3"	+1.5"
-400 kHz	+6' 8"	+1' 9"	+6.5"	+2.5"	+1.25'
-300 kHz	+5'	+1' 4"	+5"	+1.75"	+1"
-200 kHz	+3' 4"	+10"	+3.25"	+1.25	+5/8"
-100 kHz	+1' 7"	+5"	+1.5"	+1/2"	+3/8
0 kHz	0	0	0	0	0
+100 kHz	-1' 7"	-5"	-1.5"	-1/2"	-3/8"
+200 kHz	-3' 4"	-10"	-3.25"	-1.25	-5/8"
+300 kHz	-5'	-1' 4"	-5"	-1.75"	-1"
+400 kHz	-6' 8"	-1' 9"	-6.5"	-2.5"	-1.25'
+500 kHz	-8' 4"	-2'	-8"	-3"	-1.5"

Example:

You have measured the SWR of your 40 meter dipole at various frequencies across the band. You have determined that the SWR is lowest at 7.00 MHz. You actually want the lowest SWR to occur up in the sideband portion of the band, so you need to move resonance up in frequency about 200 KHz.

According to the chart, to move +200 KHz on 40 meters, you will have to shorten each leg of the dipole 10" (-10"). The overall length of the antenna is shortened a total of 20 inches.

Lengthening or shortening the antenna is done at the end insulators. To shorten the antenna, unwind the antenna wire as it wraps around itself at the end insulator. Move the insulator several inches toward the center of the antenna. Re wrap the antenna wire to secure the end insulator. Do not cut the wire. Wrap it back around the antenna wire. You may need to increase the antenna later.    [From Radio Works / DXZone]

MODES or TYPES OF TRANSMISSIONS / EMISSIONS

The type of emission is often expressed as a three digit code in a format set by the I.T.U; for example J3E identifies the type of emission as amplitude modulation telephony, single sideband, with suppressed carrier - i.e. the familiar Single Side Band Speech transmission while F3E indicates frequency modulation telephony e.g. the familiar NBFM voice and A3E would be double side band amplitude modulated telephony i.e. the typical AM speech transmission.

Some of the frequently encountered meanings for each of the three digits are shown in the tables below. The modes highlighted in red are perhaps the most regularly encountered types on the amateur bands:

N	Unmodulated carrier
A	Double-sideband amplitude modulation (AM)
J	Single-sideband using suppressed carrier (Typical amateur SSB)
R	Single-sideband with reduced or variable carrier
H	Single-sideband with full carrier
F	Frequency Modulation (Typical amateur NBFM)
G	Phase Modulation
C	Television, using amplitude modulation with vestigal sideband
K	Pulse amplitude modulation
L	Pulse width modulation

0	No modulating signal
1	One channel containing digital information, no subcarrier
2	One channel containing digital information, using a subcarrier
3	One channel containing analogue information
7	More than one channel containing digital information
8	More than one channel containing analogue information (e.g. band 2 v.h.f. stereo broadcasts)
9	Combination of analogue and digital channels

N	No transmitted information
A	Aural telegraphy such as Morse Code - i.e.decoded by ear
B	Electronic telegraphy e.g. RTTY & digital modes decoded by machine
C	Fax transmission
D	Telemetry e.g. data collection or Telecommand e.g. remote control
E	Telephony (voice and sounds)
F	Video (television)

                                        Information compiled by M0MTJ


Below is a listing of all the various ways radio and TV signals are broadcast :

A1A -telegraphy (on - off keying) without modulation by an audio frequency.
A1B -amplitude modulation telegraphy with automatic reception, without using a modulating subcarrier.
A1D -amplitude modulation data transmission, double sideband, without using a modulating subcarrier.
A2A -on-off keying telegraphy using one or several modulating audio frequencies, or on-off keying telegraphy of an amplitude modulated emission.

A2B -amplitude modulation telegraphy with automatic reception and using on-off keying of the modulating subcarrier.
A2D -amplitude modulation data transmission, double sideband and using a modulating subcarrier.
A3C -amplitude modulation facsimile; the main carrier is modulated either directly or by a frequency modulated subcarrier.

A3E -amplitude modulation telephony, double sideband.
C3F -television, in amplitude modulation, with vestigial sideband.
F1A -telegraphy (keyed by frequency variation).
F1B -frequency modulation telegraphy with automatic reception, without using a modulating subcarrier.
F1D -frequency modulation data transmission, double sideband, without using a modulating subcarrier.
F2A -on-off keying telegraphy of an audio frequency for frequency modulation, or by on-off keying of a frequency modulated emission (special case: unkeyed frequency modulated emission).

F2B -frequency modulation telegraphy with automatic reception and using on-off keying of the modulating subcarrier.
F2D -frequency modulation data transmission, using a modulating subcarrier.
F3C -modulation frequency facsimile, by direct modulation of carrier frequency.
F3E -frequency modulation telephony.
F3F -television with frequency modulation.
G1D -phase modulation data transmission, without using a modulating subcarrier.
G2D -phase modulation data transmission, using a modulating subcarrier.
G3C -phase modulation facsimile.
G3E -phase modulation telephony.
G3F -television in phase modulation.
J1D -amplitude modulation data transmission, single sideband, suppressed carrier, using a modulating subcarrier.
J2A -on-off keying telegraphy using one or several modulating audio frequencies, or an on-off keying telegraphy, single sideband, with suppressed carrier.

J2D -amplitude modulation data transmission, single sideband, suppressed carrier without using a modulating subcarrier.

J3C -amplitude modulation facsimile; single sideband, with suppressed carrier.
J3E -amplitude modulation telephony, single sideband, with suppressed carrier.
J8E -amplitude modulation telephony, independent sidebands.
K1A -on-off keying telegraphy of a carrier transmitted by pulses, without modulation by an audio frequency.
K2A -on-off keying telegraphy of one or several audio modulating frequencies, or by on-off keying of a modulated carrier transmitted by pulses (special case: unkeyed modulated carrier transmitted by pulses).

K3E -pulse modulation telephony.
R3C -amplitude modulation facsimile; single sideband, with vestigial carrier.
R3D -amplitude modulation data transmission, single sideband, with vestigial carrier.
R3E -amplitude modulation telephony, single sideband, with vestigial carrier.

RESISTOR COLOUR CODE CHART & CAPACITOR INFORMATION

Please visit my separate page for RESISTOR COLOUR CODES & CAPACITOR INFORMATION Here>





RADIO ETIQUETTE

Good Amateur Radio Etiquette:  Operating Procedures and Amateur Radio Ethics (RSGB pdf download)



GOOD AMATEUR RADIO OPERATING PRACTICES

Good Amateur Radio                    Operating Practices
Showing Consideration For Others • Remember that radio contacts are not private — the amateur radio. community is a public place. • Use language that is clear and will not offend. • Leave music to the broadcast stations. • Keep a copy of the band plans to hand and follow them. • Use amateur codes and abbreviations on amateur bands when they are appropriate (e.g. Two
Echo Zero, QSY. 73. 588) and avoid codes or jargon from other radio users (e.g. CB, PMR, military, marine) • Keep overs short as you would in a conversation — new friends might want to ioin in or conditions might change such that your signals fade away. • lf you find another station on ‘your' frequency politely ask them to move, or move your QSO to a clear frequency - propagation may have changed and they may have been there all the time. • Find a clearfrequency to tune up on and keep a note of your ATU settings for quick retuning next time you use the band.	• Answer CQ calls once then listen; only call again if no other station has been identified - be patient. •  lf the station you are calling is not working anyone near you wait a while and try again later - be patient. • Try calling CQ on bands that sound dead - others may be waiting for a call. •  Remember, there is no need for ‘CQ’ on a repeater just ‘M6XYZ listening through GB3UB’ is enough. Helping Others • Keep the hobby growing and help  newcomers to get started.	• Offer friendly advice to help others  improve their skills. • If you can hear someone calling CQ and no one is answering, give them a call, even if it is just to let them know their signals are getting out. • Always give accurate signal reports – if you need 3 repeats, they cannot be 5&9. • Inspire others to be good operators by being one yourself. • If someone needs help (e.g. with putting up an antenna) lend a hand - you may need help next time! Being Active • Use the bands without abusing the  privileges that your Licence gives you. • Join in club activities (local, national or both) – they provide an excellent opportunity to help others and to learn more about the hobby.
• Reduce power to minimum whilst tuning - it's safer for your radio and less interference to others. Calling Other Stations • Listen carefully to the CQ call — is it a general call to all or a specific call to one continent or country? • Only call if the CQ is general or for your area (e.g. ‘CQ UK’ or 'CQ Europe') or your callsign group (e.g.‘calls with zero only') your turn will come - be patient. • Always give your callsign in full and remember to send the other station’s call first (e.g. 'Delta Six Eight Charlie from Golf Echo Alpha Bravo Charlie)	Learning More • Familiarise yourself with your own radio equipment (e.g. Know how to work ‘split’) • Read through the whole of your Licence - the training doesn’t cover all of it but you must comply with the parts that apply to you. • Read up on topics of interest (the RSGB operating manual is a mine of information). • Try new ways of operating e.g. back- packing, data modes, satellites, gaining awards, taking part in contests.	• Experiment with different antennas  bands, modes – learn by doing. • If you don’t know something, try to find the answer, search the web, read some books or ask for help. • Set yourself some goals e.g. To upgrade your licence by the end of the year, to work 100 countries in a year / month / weekend, to learn Morse and get a proficiency certificate.
Download this RSGB Leaflet here:     http://www.rsgb.org/tutors/pdf/good_operating_practices.pdf Join the RSGB - The Radio Society of Great Britain  -  http://www.rsgb.org/ Get A Licence  -  http://www.rsgb.org/getlicence/ Operating Procedures and Amateur Radio Ethics (IARU / RSGB pdf download)

THE RADIO AMATEUR IS :          

CONSIDERATE... never knowingly operates in such a way as to lessen the pleasure of others.         

LOYAL... offers loyalty, encouragement and support to other amateurs, local clubs and the American Radio Relay League, through which Amateur Radio in the United States is represented nationally and internationally.         

PROGRESSIVE... with knowledge abreast of science, a well-built and efficient station and operation above reproach.         

FRIENDLY... slow and patient operating when requested; friendly advice and counsel to the beginner; kindly assistance, cooperation and consideration for the interests of others. These are the hallmarks of the amateur spirit.         

BALANCED... radio is an avocation, never interfering with duties owed to family, job, school, or community.  

PATRIOTIC... station and skill always ready for service to country and community.





I will listen and listen, and then listen again before calling.

I will only call if I can copy the DX station properly.

I will not trust the DX cluster and will be sure of the DX station's call sign before calling.

I will not interfere with the DX station nor anyone calling and will never tune up on the DX frequency or in the QSX slot.

I will wait for the DX station to end a contact before I call.

I will always send my full call sign.

I will call and then listen for a reasonable interval. I will not call continuously.

I will not transmit when the DX operator calls another call sign, not mine.

I will not transmit when the DX operator queries a call sign not like mine.

I will not transmit when the DX station requests geographic areas other than mine.

When the DX operator calls me, I will not repeat my call sign unless I think he has copied it incorrectly.

I will be thankful if and when I do make a contact.

I will respect my fellow hams and conduct myself so as to earn their respect.



CALLING CQ:

e.g. your call sign is CD456

1. Find a clear frequency. If not sure whether the frequency is clear, ask before proceeding.

2.Call "CQ CQ CQ. This is Charlie Delta Four Five Six calling CQ CQ CQ.  Charlie Delta Four Five Six, CD456 calling CQ and waiting for any call."

Listen for any return call.

3. You hear "Charlie Delta Four Five Six this is Echo Foxtrot Seven Eight Nine, EF789 calling."

4. You respond by saying "Echo Foxtrot Seven Eight Nine this is Charlie Delta Four Five Six.  Thank you for the call your signal is 59 (give accurate signal report using the RST system). My name is [your name] and my QTH is [your location]. How do you copy my signals? EF789 this is CD456 over."

5. Engage in conversation about other topics (location, weather, type of radio and antenna etc) - Find ways to get to know each other rather than simply exchanging signal reports and 73s!

6. End an HF contact by giving both call signs and signing off. For example: "... thank you Jim for the contact and 73 to you and your family.  EF789 this is CD456 signing off and clear."
(Adapted from HamSphere text)

Amateur radio etiquette:

* Do not transmit before first checking that the frequency is clear.

* If more than one station responds to your call and you can hear one call clearly then simply respond to that station as described.

* If only parts of the call sign is heard (e.g Foxtrot Whiskey or what ever) then in step it may be wise to respond by saying
"the station with the Foxtrot Whiskey call sign please make your call." When the complete call sign is established the QSO can continue.

* Be polite at all times rand promote friendship.  If not, avoid transmitting.

* Set a good example especially for short wave listeners who may be thinking about becoming an amateur.

* Be a good listener- make some brief nots to keep track of topics / subjects etc.

* Always reply to CQ calls if possible, and call CQ yourself.  It helps keeps amateur radio alive.

* Speak clearly and slowly, especially when giving your call sign to someone you have never worked before.

* Try to keep track of everyone in the QSO.  Hopefully someone has assumed the role of "traffic director" to make sure everyone has a chance to contribute to the discussion.  If not, don't hesitate to do it yourself.

* Make it clear at the end of each transmission which station is expected to transmit next.

* Operate on frequencies that are in whole KHz (e.g. 14.325 Khz). This alleviates ambiguity and makes it easier for everyone to be on the same frequency.

* Allow  enough separation between between your transmission and other transmissions so as not to cause adjacent channel interference. e.g. 3 kHz.
(Adapted from HamSphere text)






British / Imperial Standard Wire Gauges  - S.W.G  converted to diameter in millimetres and inches

Standard Wire Gauge - British / Imperial - converted to diameter:

American Wire Gauges  - A.W.G. converted to diameter in millimetres and inches

American Wire Gauge - converted to diameter:

UK Source for Silver Plated PTFE (Teflon) covered wire for winding higher power baluns:
http://wires.co.uk/acatalog/ptfe_covered.html
14awg / 16 swg or 0.16 mm dia wire
12awg / 14swg 0.2mm dia wire and larger toroid for higher powers.

Toroid Dimensions - typical physical dimensions of iron poweder toroidal cores