IRLP LINKING Peter Barry VA 6 PJB KE

IRLP LINKING Peter Barry, VA 6 PJB / KE 5 HQC 12/2/2020 1

Topics of Discussion n n n n 12/2/2020 What is IRLP? Basic Node Set up Direct Connect to Repeater Connecting With a Link Radio How IRLP works Local IRLP Nodes Reflectors Raspberry Pi Pi. RLP 2

Invented and Programmed by Dave Cameron, VE 7 LTD in 1997 n First nodes Vancouver and Saint John, NB… now more than 1700 n 12/2/2020 3

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How IRLP WORKS n Voice-over IP (Vo. IP) streaming n “Speak Freely” software for voice n Runs under Linux…. more stable than Windows, open source 12/2/2020 6

IRLP Vo. IP 1. Sample analog voice with PC sound card to get a continuous mono 16 -bit digital stream of raw audio at 8000 Hz (120000 bps). n 12/2/2020 2. Compress the audio to reduce the size of the stream by a factor of four (32000 bps) 7

IRLP Vo. IP 3. Split the sample into small chucks (or packets)and transmit the packets to the remote host using a User Datagram Protocol (UDP) stream. UDP does NOT confirm the reception of packets, so it uses a "fire and forget" method. . 4. Receive the packets on the remote host and join them back into a 4 -bit stream. n 12/2/2020 8

IRLP Vo. IP 5. Uncompress the ADPCM stream back into an 16 -bit raw stream of audio and play the raw audio stream through a digital to analog (D/A) converter (the output device of the PC sound card) 12/2/2020 9

IRLP Vo. IP The control software controls the stream using carrier operated squelch (COS) or continuous tone coded subaudible squelch signals (CTCSS) to start and stop the stream. When COS is present, the computer detects it through the IRLP interface board. 12/2/2020 10

IRLP Vo. IP The PTT is controlled by the buffer which joins the split packets back into the audio stream. The IRLP interface board receives a "transmit" signal from the computer while there are packets in the buffer, and a "unkey" command when the buffer is empty. 12/2/2020 11

IRLP Vo. IP DTMF The user interfaces to the IRLP computer using DTMF signals sent over the radio. DTMF sequences are owner programmable, and can accomplish almost any function imaginable. The DTMF signals are detected on the IRLP interface board and sent directly to the computer in binary, where they are converted into numbers. A DTMF software program then runs commands on the computer depending on the code entered. 12/2/2020 12

IRLP CALGARY AREA CALGARY: 1230 VE 6 ZV 444. 275 1810 VE 6 PWT 147. 550 simplex 1537 VE 6 SQU 146. 895 simplex 1260 VE 6 OIL 146. 610 (connect to SARA backbone 660* / 661*) 12/2/2020 13

IRLP CALGARY AREA AIRDRIE 1860 VE 6 JBJ 147. 5400 simplex OKOTOKS 1483 VE 6 LK 147. 51 (FARS simplex, not connected to network) 12/2/2020 14

IRLP Direct Connect Direct connect - repeater (node) "A" connects direct with node "B". With this type of link the two nodes are interconnected and no other IRLP connections are possible. 12/2/2020 While repeaters "A" and "B" are connected, all local traffic on each repeater will be heard on the other repeater as well. 15.

IRLP Direct Connect n 12/2/2020 Node Status www. irlp. net 16

IRLP Reflectors “Reflector” is a Linux computer with a high bandwidth connection capable of allowing many repeaters to be interconnected together by streaming the received audio back to all other connected stations. It does not have its own radio connection. . 12/2/2020 17

IRLP Reflectors Each reflector has 9 sub channels allowing up to 10 separate virtual reflectors to operate. These are identified by the last digit. For example - 9250 is the main channel with 9251, 9252 9253 etc being virtual reflectors with identical capability as the main channel. 12/2/2020 18

IRLP Reflectors Check on reflector status at: http: //status. irlp. net 12/2/2020 19

IRLP Reflectors Check on reflector status at: http: //status. irlp. net 12/2/2020 20

IRLP Discovery Reflector 12/2/2020 21

IRLP REFLECTOR NETS 12/2/2020 22

Raspberry Pi 12/2/2020 23

Raspberry Pi board 12/2/2020 24

Pi. RLP 12/2/2020 25

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