Formation Telecom Radio 03 December 2020 Telecom type

Formation Telecom: Radio 03 December 2020

Telecom type sum-up (early 2016) 70 bases in total: § 31% Vsat => 22 bases in 9 countries (32% in 2013…) § 36% DSL or Fiber optic => 25 bases including 11 capitales (33% in 2013… 14 capitales) § 27% Radio internet(Wifi/Wimax/WLL) => 16 bases including 9 capitales (20% in 2013…Radio becomes better than DSL…) § 50% Radio HF/VHF => 10 missions (mainly africa) § 6% 3 G keys => 3 bases (8% in 2013, but explode for backup use…) § 0% still with BGAN => 0 bases… (7% in 2013)

Electromagnetic wave § Photon § Caracteristics of a wave: • Amplitude • Frequency (Hz) • Lenght (m) • Speed (light speed) : 03 December 2020 3

Radio Frequencies 03 December 2020 18 MHz Band: 18068 - 18100 CW 18100 - 18109 Digimode, CW 18109 - 18111 IBP 18111 - 18168 Phone, CW 4

Waves transmission trough antennas The perfect antenna has the same physical length than the frequency we want to use (reception or transmission). In this case almost all the power of the transceiver is tranmited into electromagnetic wave. Electromagnetic wave Transmission Reflected power If the antenna is not well choose of if there is to many obstacles, the power of the transmission is dangerously reflected into the transceiver. Electromagnetic wave Tranmission 03 December 2020 Electromagnetic wave Reflected power 5

Radio material Managing the relfected power DANGEROUS ! The only feed back you have : SWR meter GOOD PERFECT 03 December 2020 6

Storm Lightning protection Lightnings can go up to 300 000 volts So we need to protect the radio antennas And radio antennas are a important target. 03 December 2020 7

To optimize the Radio transmission Technicaly speaking : § NEVER TOUCH THE radio ANTENNA WHILE TRANSMITING ! § Position your radio antennas as hight as possible (6 meters) except for NVIS, far from any obstacle. § Take great care of the connections (grease and silicone). § Take great care of the cables (respect lenght, do not bend). § Respect the earth connection. 03 December 2020 8

HF radios 03 December 2020

Connecting HF Radios (ACF Doc…) : Do not forget the earth connection (half the antenna ! Double the performance. . . (see annexe) 03 December 2020 10

Connecting HF Radios (ACF Doc…) : Do not forget the earth connection (half the antenna ! Double the performance. . . (see annexe) 03 December 2020 11

To optimize the HF transmission Topview Sideview Antenna position 03 December 2020 12

VHF radios 03 December 2020

VHF material GP 340 16 channels 136 – 174 MHz GM 340 5 watts (Tx) 8 to 14 hours autonomy Computer programming 265 euros 6 channels 136 – 174 MHz 25 Watts (Tx) Computer programming About 300 euros Antenna: As high as possible 03 December 2020 14

VHF repeater In duplex mode : one frequency to transmit, another one to receive. Duplex § § TX: 155 725 KHz VHF contact is similar to visual contact VHF reapeater can overcome the obstacles. RX: 155 775 Khz Duplex TX: 155 775 Khz RX: 155 725 KHz In simplex mode : the same frequency to tranmit and to receive. 03 December 2020 Simplex TX-RX: 155 250 KHz 15

VHF RADIOTESTS § If the coverage is not sufficient (< green zone for ex), => IMPROVE THE COVERAGE Material VHF Handset Power Altitude 5 watts About 2 meters Range 03 December 2020 - VHF Mobile 25 Watts About 3 meters + VHF Base 25 Watts About 6 meters ++ VHF Repeater 25 Watts About 20 meters +++ 16