Local repeaters and frequencies


Location Call Sign CTCSS F (in) F(out) Type
Sheffield GB3NA 71.9Hz 145.0125 146.6125 FM Analogue
Chesterfield GB3EE 71.9Hz 433.300 434.900 FM Analogue
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
Barnsley IO93HO GB7-YD-B None 430.5125 439.5125 D-Star
Barnsley IO93HO GB7-YD-C None 145.075 145.675 D-Star



                                                 Digital Voice (DV) Repeater Systems Available in Sheffield   DMR , Fusion and D Star.

                  145MHz 430MHz 1.2GHz    
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



ETSI 1,II,III AMBE 12.5KHz           Y   GB7SN M1ERS
    MD-380                     Y      
Yaesu Fusion Digital System Fusion FT1D   System Fusion ETSI   C4FM (AMBE chip) 12.5KHz         P       Y   GB7SH M1ERS
    FTM400DR  Wires X                    
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      
    IC 9100            Y       Y       Y       P    

                                                                                                                                        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

Hytera DMR

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

                                                                 radio fusion


                                                                                  Yaesu Fusion C4FM communications diagram



                                                 Hytera DMR Repeater System and Power Supply 19" Rack (DV-Mega System) -Sheffield IO93GH



VHF/UHF Beacons frequencies


Location Callsign Frequency Notes
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
Bristol GB3BSL 432.934           70cm IO81QJ
Ballymena GB3NGI 432.482           70cm IO65VB
Scotland GB3ANG 432.980           70cm IO86MN
St.Austell GB3MCB 432.970           70cm IO70QJ
Buxton Derbyshire GB3BUX 50.000             6M IO93BF
Inverness GB3RMK 50.060             6M IO77UO
Ballymena GB3NGI 50.063             6M IO65VB
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.

1.3GHz (23cms)

2.3GHz (13cms)

3.4GHz (9cms)

5.7GHz (6cms)

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.

Technical Data

Ohms Law



            Note:  V = E (Voltage)  on chart


  1. 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

  1. 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.

  2. 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

         50 Ω.  

         The ATU is normally a PI,T or Trani-match types.


       Feeder Impedance

          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





Here2Host providing Cloud Hosting and Web Design