Local repeaters and frequencies
|Location||Call Sign||CTCSS||F (in)||F(out)||Type|
|Sheffield University||GB3US||103.5Hz||433.000||434.600||FM Analogue|
|Sheffield IO93GK||GB7SF-B||None||430.1375||439.7375||D-Star Digital|
|Sheffield IO93GK||GB7SF-C||None||145.1375||145.7375||D –Star Digital|
|Sheffield IO93GK||GB7-SH||71.9Hz||430.9625||438.5625||YAESU FUSION|
|Sheffield SARC||GB7-SN||None||430.675||439.675||DMR HYTERA plus|
Digital Voice (DV) Repeater Systems Available in Sheffield DMR , Fusion and D Star.
|Manufacture||Name||Typical. Radio||Network||Standard||Tier||Codec||spacing||HF||2 metres||70 cms||23cms||Local Repeater||Keeper|
|Motorola DMR||Digital Mobile Radio||DM4600||DMR MARC||MotoTRBO (TDMA)||I,ii,iii||AMBE+2TM||12.5KHz||P||Y||GB7SR||M0GAV|
|Hytera DMR||Digital Mobile Radio||PD36X||
|Yaesu Fusion||Digital System Fusion||FT1D||System Fusion||ETSI||C4FM (AMBE chip)||12.5KHz||P||Y||GB7SH||M1ERS|
|ICOM D-Star||Digital Smart Technology||IC 7100||D -STAR||D-STAR||AMBE (hardware)||12.5KHz||Y||Y||Y||GB7SF -B ,C||M1ERS|
|for Amateur Radio||IC-2820||CODEC2||Y||Y|
Y = Yes available P = Possible if implemented
Tier I,II = Conventional
Tier III = Trunked
AMBE = Advanced Multi-Band Excitation [ Vocoder- Developed by Digital Voice Systems inc. DVSI ]
MARC = Motorola Amateur Radio Club
TDMA =Time Division Multiple Access
ETSI = European Telecommunications Standards Institute.
CODE PLUGS = Configure radio with associated software for network etc.
Yaesu Fusion System
Supports both Analogue FM and Digital C4FM - [ FM into repeater, FM out of Repeater] - [C4FM into repeater ,C4FM out of repeater] - [C4FM into repeater , can also provide FM out of repeater ]
WIRES X = Wide-coverage Internet Repeater Enhancement System
The SARC Hytera repeater - works on the Hytera DMR system via. DMR radios configured for the Hytera network ( Brandmeister ), but can also talk with existing D-STAR users on slot 2. DMR implements TDMA and can handle two stations at the same time which are on different channels.
DMR system allocates two slots 1 & 2
Slot 1 - Local
Slot 2 - UK wide and International.
D Star works on the D-STAR network and can talk to other D-STAR radios or via. computers fitted with a D-STAR DV dongle. You can also talk to DMR radios configured for the Hytera network via. IRQDDB DCS005F output on GB7SN repeater from DCS005F.
The Motorola DMR
The Motorola DMR system can talk to other DMR radios configured for the DMR MARC network but can't link up with the D-STAR or Hytera DMR systems.
For more information visit the links below to useful repeater websites:
D Star Group GB7SF Repeater Keeper M1ERS location IO93GK (Firth Park Sheffield)
DV-Mega DV- Mega provide D Star and DMR Hot Spots shields for on RPi and Arduino single board computers.
South Yorkshire Repeater Group Local repeaters GB3NA,GB3YR,GB3EE,GB3DV,GB3US and GB3SY
GB7SN DMR Hytera Repeater Repeater located at IO93GH (Norton Sheffield)
Yaesu Fusion Repeater Keeper M1ERS located at IO93GK (Firth Park Sheffield)
Steve M1ERS, Peter 2E0BFZ and Carol 2E0CJH of SARC collect Yaesu Fusion Repeater from Lee at LAM Communications (LAMCO) Barnsley
Fusion and D Star Repeaters in 19" Rack - Sheffield IO93GK
Typical Yaesu Fusion Radio with both FM and C4FM
Yaesu Fusion C4FM communications diagram
Hytera DMR Repeater System and Power Supply 19" Rack (DV-Mega System) -Sheffield IO93GH
VHF/UHF Beacons frequencies
|Kent South England||GB3VHF||144.430 2M||Slightly east of south|
|Dundee Scotland||GB3ANG||144.453 2M||Angus Beacon north|
|Emley Moor||GB3MLY||432.910 70cm||IO93EO|
|Buxton Derbyshire||GB3BUX||50.000 6M||IO93BF|
|Buxton Derbyshire||GB3BUX||70.000 4M||IO93BF|
|Dundee Scotland||GB3ANG||70.020 4M||IO86MN|
UK Prefixes and suffixes
Most popular Q codes
|QRO||High Power||Normally >> QRP|
|QRP||Low Power||Normally 5watts CW or 10watts SSB PEP|
|QRZ||Who is calling me||Next station go ahead|
|QSY||Move or moving frequency||e.g Can you QSY to 14.180 Mhz|
|QRT||I am shutting down||Going off air and closing down|
|QRV||Active /operational /Ready||I am QRV on 160 metres now|
|QSO||A contact/conversation||We had a good QSO|
|QTH||Your station location||Home Address of station|
|QRA||Location of a station||Using QRA codes e.g IO93GH|
|QSL||Can you confirm||QSL card confirmation of contact|
|QSB||Your signals are fading||Signal strength changing up and down|
|QRM||Interference||Interference from other stations or noise|
|QRN||Static interference||Electrical storm ,crackles and spikes.|
|QRX||Break in QSO TX listen for me on return||Stopping TX for 1 mins , QRX for 1 mins|
S points and Power Output
The chart shows how much power would be required to produce the required S report at
the receive end, if 1 watt output produced a S4 report.
S4 to S5 = 4 = 6dB
S5 to S6 = 3.9 (4) = 6dB
S6 to S7 = 4 = 6dB etc.
Therefore one S point = 6 dB increase.
From S4 to S9 =1000/1 = 1000 = 30dB (5 x 6dB)
If you have foundation licence with an output of 10 watt the chart shows that your
Signal would be only 10/100 = -10dB down on a station running the normal 100watts.
Since one S point is around 6dB then that would represent a loss of only 10/6 = 1.6 S
points. With a good antenna and plenty of patience , 10 watts can work the world.
Main HF Band Frequencies for Amateur Bands
We have Transceivers and a full size G5RV for these bands. When using HF transceiver with the G5RV antenna then the ATU settings must be checked , before using . (See the tuning chart provided which shows the L & C settings for each band), when changing bands, start ATU tuning at low power then raise power when the SWR is at an acceptable value , ideally below 1.5:1.
10m 28.000 – 30.000MHz (Note: CB transceivers 11m = 27MHz)
160m 1.800 – 2.000 MHz Called Top Band
The HF Amateur bands are included within the SW (Shortwave) section of the freq. chart below.
VHF Amateur Bands (We have radios and beams erected for 2metres & 70cms at the shack)
6 metre band - 50 to 52MHz
4 metre band – 70 to 72MHz
2 metre band - 144 to 146MHz
70cms band - 430 to 435MHz
The SWR on these bands would normally be pre-set to acceptable values to cover the SSB sections of the bands which would be used for DX and contests.
Microwave bands (No equipment in Shack for these bands) but MX0RCU vehicle as a IC9100 which as HF, 6, 4, 2, 70cms and 23cms.
10GHz (3 cms)
It is planned to assemble the adjustable tower and install the a HF multi-band beam
plus 6metre and 4metre beams for contesting from the PortaKabin.
This would mean running the petrol generator to run reasonable power.
Note: V = E (Voltage) on chart
Transceiver feeds 100 watts into a 50Ω load what is the RF voltage across load ?
R = E 2/W therefore E = sqrt ( R x W) = sqrt (50 x 100) = sqrt(5000) = 70.7 Volts
A dipole antenna tuned to the required frequency is fed by 100watts RF .
what is antenna current ? From Q1 Voltage = 70.7 Volts
Therefore current = E/R = 70.7/50 = 1.414 Amps.
The total resistance of a cable feeding power to a radio shack in the garden is 0.5 Ω , the current to be used in the shack is 10amps. What is the voltage drop over the cable run? E = I x R = 10 x 0.5 = 5 volts .
The above equations assume that the circuit is purely resistive which is OK for both DC
and AC circuits. But in radio work, most of the circuits are not purely resistive and are
made up of three components resistance, inductive reactance and capacitive
reactance and the combined quantity is called impedance Z.
It is beyond the scope of this short document to go any deeper into impedance other
than to say that the tuned circuits and antennas etc. used in radio have both
inductive reactance, capacitive reactance and resistance.
A tuned circuit or antenna is tuned to resonance when the inductive reactance 2πfL
= capacitive reactance 1/2πfC.
2πfL = 1/2πfC.
f r = 1/ (2π √LC)
Reducing the capacitance or inductance, increases frequency.
Increasing the capacitance or inductance, reduces frequency
An Antenna Tuning Unit (ATU) changes the values of both inductance and
capacitance in order to match an antenna impedance to the transceiver output of
The ATU is normally a PI,T or Trani-match types.
The Impedance of the feeder cable is called the characteristic impedance because
the Impedance is determined by the characteristics of the feeder dimensions and
the dielectric material. The mathematics involved can be very complex and not really
required and we just accept the result.
TV VHF/UHF Coaxial cable (RG59) Zo = 75Ω which matches the impedance of
TV Beam antennas and produces the least attenuation of the signal.
For Amateur radio and CB radio the coaxial feeder is used for both receiving and
transmission and a lower Zo of 50Ω Is used since this value produces less power
loss during transmission and also matches beam antennas and Transceivers which
are designed for the lower impedance of 50Ω.
The two most common coaxial cables used in Amateur radio are :-
RG58 (UR43) Zo = 50-52Ω and RG213 ( UR67), Zo = 50Ω.
Coaxial Cable Data.
Various Coaxial cable types
Reference RSGB Comm. Handbook
Gain, Loss and Decibels
|Gain x2||+3dB||Loss ½||-3dB|
|Gain x 4||+6dB||Loss ¼||-6dB|
|Gain x 10||+10dB||Loss 1/10||-10dB|
|Gain x 100||+20dB||Loss 1/100||-20dB|
|Gain x 1000||+30dB||Loss 1/1000||-30dB|
|Gain x 10000||+40dB||Loss 1/10000||-40dB|
Example 400Watt = 4 x 100 watts = + 6dB + 20dB = +26dBW
1000watts = +10dB + 100dB = +30dBW
Amplifiers and Antennas produce a positive gain in +dB
Feeders, filters and attenuators produce a negative gain or loss –dB
Antenna gains are quoted in two quantities which need to be understood.
dBi = Gain in reference to a isotropic antenna (A ideal theoretical antenna of no use in practise) .
dBD = Gain in reference to a dipole
dBD= dBi gain - 2.15
The most practical unit is dBD since the effective radiated power erp = power x gain in dBD.
e.g A Beam antenna of 10dBd gain is fed with 100 watts what is the erp = 10 x 100
= 1000 watts.
If a similar antenna gain was quoted as 10dBi then the erp would be much reduced since dBD = dBi-2.15 = 7.05dBD and erp = 7.05 x 100 = 700.35 watts.
Some manufactures quote dBi instead of dBD because it is a higher numerical value of gain and it looks like you are getting more for your money, but you are not.
Actual useful gain on 2m = (dBi – 2.15) = 7.5-2.15 = 5.35 dBD and on 70cms = 7.15dBD
Simple HF dipole
A simple dipole can be made for any band but it is best to use a half wave of the lowest band possible and the higher bands with are multiples of half wavelength can also be used.
Open feeder or 300Ω - Ribbon cable direct to balanced input on ATU
Wire lengths of half wave ( λ/2) dipoles in metres or feet/inches are listed in columns 4 and 5 respectively. Antenna wire can be ideally - 1.5mm2 or 2.5mm2 standard flexible single core cable, but any size will work. The feeder can be 50Ω coaxial cable with or without a BALUN. A BALUN would convert the unbalanced dipole to a balanced dipole and this would eliminate any current flowing in the outer coaxial braid which can cause TV interference. Twin feeder could also be used and connected directly to an ATU which has a balanced input.
G5RV Multi-Band Dipole