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site:rosston:224.2 [2018/01/12 21:56] ke5gdb |
site:rosston:224.2 [2018/01/12 22:19] (current) ke5gdb [224.2 Technical Specifications] |
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====== 224.2 Repeater ====== | ====== 224.2 Repeater ====== | ||
- | The KE5GDB 224.2MHz (pl110.9) repeater likely has the largest coverage area of all 220 repeaters in Texas. The repeater consists of a pair of Motorola CDM1550 radios, a 100 watt Henry amplifier, CX-333 antenna, and a Raspberry Pi running Allstar as a repeater controller. In addition, the Pi drives a Kenwood TM-V71a Remote Base. | + | The KE5GDB 224.2MHz (pl110.9) repeater likely has the largest coverage area of all 220 repeaters in Texas with the antenna at 1500' AGL. The repeater consists of a pair of Motorola CDM1550 radios, a 100 watt Henry amplifier, CX-333 antenna, and a Raspberry Pi running Allstar as a repeater controller. In addition, the Pi drives a Kenwood TM-V71a Remote Base. |
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===== 224.2 Technical Specifications ===== | ===== 224.2 Technical Specifications ===== | ||
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===== Temperature Sensors ===== | ===== Temperature Sensors ===== | ||
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+ | ===== Remote Base ===== | ||
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+ | A Kenwood TM-V71a is connected to the Raspberry Pi with a USB-RIM. In addition, an FTDL USB-Serial cable allows control from the Raspberry Pi. The TM-V71a is fed into a diplexer, which is then fed to a triplexer, then to the CX-333. The diplexer/triplexer arrangement allows the single antenna to drive all elements of the 220 repeater and the remote base. | ||
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+ | A Python script was written to allow full control of the TM-V71a from the command line. DTMF control is planned, but not yet implemented. | ||
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+ | ===== 220 CDM1550 Notes ===== | ||
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+ | With the additional heatsink and forced air cooling, the CDMs have no issue running 100% duty cycle at the highest power possible, 28 watts. A DS18B20 temperature sensor was embedded in the radio heatsink. Over the course of several hours of continuous transmitting, a 25°C to 32.5°C temperature rise was recorded. This indicates CDMs may be able to run at the full-rated power as long as proper forced air cooling is used. | ||
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+ | To use the CDMs in the ham band, a few adjustments need to be made to the CPS and the tuning of the radio. | ||
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+ | First, modify your CPS per [[http://ccdx.org/zedyx/mods/CDM_Mods/CDM_OOB.htm|these instructions]] ({{ :site:rosston:cps_out_of_band.pdf |backup}}). The hex values you're looking for may be in a slightly different location (off by several bytes), but you should be able to locate and make it work. | ||
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+ | The radio only operates in 12.5KHz steps. In the event that you're programming to a pair that does not divide evenly by 12.5KHz, program the radio for the nearest channel and use the tuner to warp the reference oscillator to get it on frequency. | ||
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+ | Things to adjust: | ||
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+ | * TX VCO Attenuator (for wideband use) | ||
+ | * Reference Oscillator (if not evenly spaced) | ||
+ | * Squelch Level | ||
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