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Fourpak Packet Radio Group
UK Amateur Packet Radio Conference 2004 Proceedings
Presentation 3: KISS 2.3GHz LAN - original text - HTML version
A KISS 2.3GHz Data Transceiver
Anthony Martin M1FDE
15th May 2004
2. 2.3GHz data transceiver
3. Problem
From the TVIPUG website:
"No 70cms links or user access ports at either g4xyw and g1wkk's or any new network node.
As our main network which we have painstakingly built operates at 9k6 full duplex on yes you guessed it 70cms. There are to our knowledge no designs for transceivers for high speed data for higher bands which are readily reproducible."
4. Why KISS is preferred
5. RF Module
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| The RF Module
| its source...
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6. PRR Transceiver
- Personal Role Radio
- Section-level radio
- Equip every soldier
- Replaces hand signals and shouting
- High volume, low cost
- Hands-free operation
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7.
Soldiers of Black Watch Regiment, Op Telic
8. Module Block Diagram
9. RF Board
10. Specifications
- Data rate 40kbits/sec (raw on-air)
- Occupied bandwidth 1.3MHz (89% power)
- 31 bit spreading code (gold codes)
- Tx power max 20dBm (100mW)
- Rx sensitivity min -106dBm, typical -108dBm
(compare 2m FM rig -119dBm for 10dB sinad
15dB higher data rate)
- Supply 2V to 3.2V, 300mA at 3V (Tx)
- Frequency stability 2.5ppm (1ppm typ)
11. Microcontroller
- Atmel 90S8515
- 4MHz AVR RISC CPU
- 8k bytes Flash program
- 512 bytes (yes bytes) RAM
- 512 bytes EEPROM
- Serial port
- In-system programming (ISP)
- Software written in C
- DSSS chipset has block data buffer
- Micro controls both frequency and Tx power
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12. Hardware Adaptations
- 3V to RS232 level converters
- MAX3232
- 3V LDO supply regulator
- LT1086CT
- Status LEDS
- Tx, Rx, Power
- SMT connector
- Ideally needs PCB to mount
- Really ice-cool case
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13. Software Adaptations
- KISS protocol
- Control packets set frequency & power
- Test modes
- For measuring frequency, power
- Higher speeds?
14. Difficulties (Challenges)
- Small RAM - shortage of buffer space
- Limits on MAXFRAME and MAXWIN
- Limits on MTU
- Packet fragmentation forced
- Serial data
- Limited baud rate choices – 4.0MHz xtal
- Max standard rate 19,200
- Non-std rates / RS422?
15. What Frequency?
| 2322.000 - 2400.000 | All modes
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| 2322.000 - 2355.000 | ATV and ATV repeater outputs
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| 2355.100 - 2364.000 | Repeater links
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| 2355.100 | Packet radio (200KHz b/w)
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| 2355.300 | Packet radio (200KHz b/w)
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| 2356.000 -2360.000 | High speed data
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| 2364.000 | Packet radio (1MHz b/w)
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| 2365.000 - 2370.000 | Repeaters
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| 2370.000 - 2390.000 | ATV
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| 2390.000 - 2392.000 | Moonbounce
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| 2400.000 - 2450.000 | Satellites
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16. Project Status
- 4 RF modules tested
- 2 cased units built and tested
- Parts for 2 more
- ISP built and tested - Win9x/NT
- AVR KISS Firmware
- Demo network
- Trial links
- Antenna experiments
17. Link Budget 145 MHz
Link budget for two 2m band handheld radios
- Frequency = 146 MHz, Tx 5 watts, Dipole antennas, Rx sensitivity -118dBm, Path freespace
- Transmit ERP = +37 dBm
- Maximum path loss = 37 + 2 + 122 = 161 dB
Path loss = 37 + 20*log(distance) + 20*log(Fmhz)
20*log(distance) = Path loss - 37 - 20*log(Fmhz) = 81
- Maximum Distance = 10,900 miles
- Amateur paths dominated by other losses, massively wasteful of capacity.
18. Link Budget 2.4 GHz
Link budget for 2.4GHz radios
- Frequency = 2.4 GHz, Tx 100mW, Dipole antennas, Rx sensitivity -108dBm, Path freespace
- Maximum path loss = 108 + 20 + 2 = 130 dB
Path loss = 37 + 20*log(distance) + 20*log(Fmhz)
20*log(distance) = Path loss - 37 - 20*log(Fmhz) = 25.4
- Maximum Distance = 18.6 miles
- Real problem is obstructions, not distance
- Mesh networks "every station a digi"
- Capacity increases with number of nodes
19. Contacts and Links
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