The long-awaited and much-anticipated upgrade of the K9VI and K9HEP repeaters has finally started. The upgrades involve the 51.91/52.91 6 meter repeater, the 145.33/144.73 2 meter repeater, the 224.700/223.100 222MHz rerpeater, and the pair of UHF repeaters located on site: 443/448.200 and 443/448.475MHz.
The 6 meter repeater utilzes a pair of antennas seperated by approximately 400 feet. The antennas are both located at approximately 450 feet AGL. The repeater consists of a high power Motorola Micor 375 watt base station operating at 250 watts. It is under the control of a CAT 300 repeater controller. The 222MHz repeater is linked to 6 meters and is also under control of the CAT 300. We plan to add a third antenna so that receive diversity can be utilized to improve performance. A LDG RVS-8 voter is on-site for this purpose. It will also be used to vote between a pair of 222MHz antennas and linked, remote receive sites.
The 2 meter repeater is currently a Motorola 125 watt MTR-2000 analog repeater but will soon be upgraded to a 125 watt Quantar with P-25 digital capabilites. It will be linked to the 443.475MHz UHF system full time.
The 443.475 UHF repeater is currently a 25 watt Quantar but will soon be upgraded to a 110 watt Quantar. The 25 watt unit will be configured for switching between 443.200 and 443.475 MHz and will act as a backup unit in the case of failure of either main.
The 443.200 MHz repeater is currently a 110 watts Quantar. It will be linked to the 6m / 222 MHz systems. It will also have IRLP capabilites.
The UHF systems are combined into a single antenna at 475 feet AGL. The combiner utilizes a Celwave 4-port transmitter combiner that has been modified. Two of the 4 ports have circulators and are tuned for the respective transmit frequencies. The other ports do not have circulators and are tuned for the receive frequencies. Each transmit port is fed to a pair of Celwave BpBr cavity filters that have been tuned for a passband at the respective transmit frequency and one notch each at the receive frequencies. Each receive port is fed to a single BpBr cavity that has its notch tuned to 443.375MHz. The resultant notch is equally spaced between each transmitter freqeuncy. The overall result is just under 3dB loss at each port (slightly less on each RX port) and a minimum of 115dB isolation between RX and TX ports. The circulators insure IM is not generated due to the close spacing of the transmitters.
Above the large 4-port combiner is a 6 pole bandpass filter. It is tuned to pass 447 - 450Mhz and is fed from a second UHF antenna at 330 feet AGL. This signal is fed to an amplified multicoupler which, in turn, feeds a pair of AstroTAC UHF receivers. These are intended for use in a voted system to improve mobile performance by reducing multipath effects.
The 222 MHz system is actually a pair of Spectrum Engineering Pty Ltd (Australia) 50 watt repeaters. The are configured as main and alternate main. Both receivers feed the voter and use seperate antennas to, once again, add receive diversity to the system.
In addition, the 222 MHz rack also contains 4 VHF AstroTAC receivers tuned to the National Weather Service on 162.450 (Racine, WI), 162.475 (Rockford, IL), 162.500 (Crystal Lake, IL), and 162.550 (Chicago). The audio from these receviers feeds a Sage ENDEC EAS decoder. Alerts for McHenry, Boone, Lake, Cook, Kane, DuPage, and Winnebago Counties in Illinois and Walworth, Kenosha, Racine, and Milwaukee Counties in WI are rebroadcast through the 6 meter, 222, and 443.200MHz repeaters automatically.
Finally, the non-ham GMRS repeater that I built about 14 years ago has also undergone an upgrade. The old R-100 Motorola repeater has been replaced with a Quantar derated to 50 Watts TPO. The antenna is an 8 bay, open dipole antenna at 200 feet AGL. Thus, the GMRS system is currently operating at maximum allowable power and antenna height. Please drop me an email if you use the system and let me know how the coverage and operation is. Unlimited use of the system has been granted to the LAG group for their public service-related operations. Please drop me an email for permission to utilize the system; a simple note with your GMRS callsign will suffice for my records.
Additional descriptions will be added as work continues on the system.
