Microbit RRC-1258 MkII(s) Uživatelský manuál Strana 1

iComputersinAmateur Radioby Steve White, G3ZVWwith contributions by other authorsRadio Society of Great Britain© RSGB

50Computers in Amateur RadioEZNEC is de-facto the amateur standard antenna modellingpackage, and is relatively easy to use. EZNEC stands for Easy NEC!

51Antenna Modellingexample models. Left click on this, then click ‘Open’. The ControlCentre window reveals we have opened the model file BYDipole.EZw

52Computers in Amateur RadioClick on the Trans Lines button in the Control Centre window toopen the blank Transmission Line window – Fig 4.5.We now en

53Antenna ModellingThe Cond (Ground Conductivity) and Diel Constant in thesample model are set to those for very good ground. To make themodel more re

87Software Defined Radio7.Software Defined Radioby Mike Richards, G4WNCMicroprocessors have had a massive impact on just about all modernelectronics a

88Computers in Amateur Radiowe ought to take a look at these before moving-on to real-world sys-tems. They are:Analogue to Digital Conversion (ADC),In

89Software Defined Radioentire spectrum from VLF through to 30MHz or more! Most of theseemploy some digitally switched band-pass filtering close to th

90Computers in Amateur RadioI’ve shown an IQ polar diagramin Fig 7.3a-c. Here the I axis repre-sents a change in amplitude of thecarrier wave, whilst

91Software Defined Radiooscillator carriers at 0 and -90 degrees and then combines the result, asshown in Fig 7.5. This makes for a very elegant modul

109Internet Remote Operation9.Internet RemoteOperationby Wojtek (Berni) Bernasinski, G0IDA, SP5GUThe technological advances in computing and microcont

iiiContentsChapter Page1. Introduction 12. Datamodes 53. Logging Softwar

110Computers in Amateur RadioAdvantagesA clear advantage of operating remotely is that the station can beconnected to a large antenna, perhaps a full

111Internet Remote Operationdisadvantages but they could be enough to put you off such a project.I have been very lucky at the remote end, as I have f

112Computers in Amateur Radiowidth which the audio channel uses is approximately 85kbps usingmode ‘0’ and the codec G711 at a sampling rate of 8KHz. O

113Internet Remote OperationWeb SwitchThe clever little Web Switch 1216H from the samemanufacturer can be seen in Fig 9.3. I say ‘clever’, asit can no

118Computers in Amateur Radio10.D-Starby Dave Thomas, 2W0RUHContrary to widespread belief, Digital Smart Technologies for AmateurRadio (D-Star) is a c

119D Stardeals on the purchase of a repeater if a number of radios were bought,which allowed clubs and individuals to enter into negotiation with thos

120Computers in Amateur Radioreceive end can request retransmission if a packet is received witherrors, whereas D-Star is a one-way protocol, so no re

121D StarIdentification DataReceived Repeater Callsign Callsign of the repeater that is to receivethe packetSend Repeater Callsign Callsign of the rep

122Computers in Amateur RadioD-Star systemlayoutWe will begin withthe D-Star repeater.Unlike an analoguerepeater whichoperates on aparticular bandwith

19Antenna Modelling 48APRS 130Datamodes 5, 34AmTOR 10ASCII 8Baudot (RTTY) 6Clover 14Facsimile 16Hellschreiber 13MFSK 12Morse 5MT63 14Olivia 9Packet R

5DatamodesComputers have revolutionised datamode operation for radio amateurs.With their advent we were no longer restricted to the use of huge,clunki

19Live Internet Applications 166Chat Rooms 166DX Clustering 169Live VHF DX Maps 170Near Real-time Magnetometer 171Near Real-time MUF Map 172Online Re

6Computers in Amateur RadioWith Morse, the dots, dashes and spaces are all intended to varyin proportion to one another, as transmission speed varies.

7Datamodesreceive and decode with a mechanical machine. This is primarily be-cause, irrespective of the sending speed, not all the characters take the

8Computers in Amateur RadioMark-Space shifts being 85Hz, 170Hz, 425Hz or 850Hz. The mostpopular shift used by radio amateurs on HF is 170Hz. 85Hz tend

9DatamodesWhilst not supporting error detection or correction, PSK31 is self-synchronising. It is very good at working through noise, indeed it iscopy

48Computers in Amateur Radio4.Antenna Modellingby Ian Birkenshaw, G4UWKIntroductionThe average computer-literate radio amateur might initially ask why

49Antenna Modellingsegments to produce the actual radiation pattern in a mathematicalprocess called ‘Method of Moments’.Readers with a strong physics