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Station K0TV Amateur radio station K0TV is located in Hudson, NH. Conveniently located near Nashua. Just minutes over the Massachusetts border less than 2 miles from US Route 3. Since I am an avid contester and VHF/UHF weak signal enthusiast, I have erected my station with the goal of being a competitive station in contests on both HF and VHF/UHF. K0TV is located on one of the highest spots in the local area. Within 1 mile, there is nothing higher. Going out three miles, there is a hill 120 feet higher 1.2 miles to the Southeast. To the east, there is a hill 200 feet higher at 3 miles. Higher hills exist at greater distances, but the radio horizon is still much less than 1 degree in any direction. The local terrain slopes off in all directions making all the antennas to act as if they were much higher than they are. The ground conductivity is also very poor resulting in a higher effective height. Because of these effects, towers at 150 and even 200 feet would not be effective. I was forced to compromise on the height as I had originally proposed towers at 100 feet with antennas extending up to 120 feet. This height was not allowed by the town. Antennas Since antennas are the keystone of any station, I will describe my present and eventual antenna and tower configuration first. My station equipment will be described below. There are three 87 foot towers. They are oriented in a V pointing South. Using the South tower as a reference, the other two towers are the Northeast tower at 47 degrees and 317 feet and the Northwest tower at 315 degrees and 294 feet. The exact position of the towers was chosen by the topography of the land; distance from the house and property lines; and aesthetic concerns to save trees. The
position of the three towers is: The South tower has a stack of two M2 5 element 20 meter yagis. The top antenna is rotatable at 90 feet. The bottom yagi is at 45 feet fixed on Europe. These antennas can be selected or operated as a stack of two. There is also a stack of 2 18 element 2 meter antennas at 110 and 95 feet rotatable on this tower's mast. There is also a stack of two 16 element 222 yagis at 106 and 98 feet. This tower also has two fixed antennas pointed South for 40 (Cushcraft 402CD) and a Tribander (TH7). An Inverted-L is planned to complete the phased array system for 160 meters. Long range plans are to add microwave antennas for 9, 5, and 3 cm. The Northwest tower currently has a 4 element monobander for 15 meters at the top and a KT34A fixed South at 45 feet. This tower also has a side mounted Inverted-L for 160 meters and a 4 element monobander for 15 meters fixed on Europe The Inverted-L will be used as part of a phased array. Planned improvements are a sloper system will be added for the 30 meter band. Planned improvements for this tower in 2010 are the installation of 70, 33, 23 and 13 cm antennas. The Northeast tower currently has a 4 element 40 meter yagi installed and operating. A 7 element 6 meter yagi is at the top of the mast. A 4 element 10 meter yagi is installed below the 40 meter antenna. Two more 6 meter yagis are installed fixed Southwest and are usable with the top antenna as a 7/7/7 stack. There are also two fixed stacks of 10 meter yagis. One is fixed on Europe and the other is fixed South. This tower will also support an Inverted-L for 160 meters that will be used as part of a phased array of any two of three Inverted-Ls. An Off-Center Fed 160/80 meter dipole is hung between the South and Northwest towers providing an antenna capable of local communication (out to about 1500 km). Three Steerable Wave Antennas (SWAs) have been installed to provide low noise receiving antennas in six directions (NE/E/SE/SW/W/NW). Although usable on 80 meters, the four square provides equivalent performance to the SWAs A four square antenna is available for 80 meters. The four square array consists of four full size 1/4 wavelength vertical elements with a phasing network and is steerable NE/NW/SE/SW. The four square is remotely switchable between CW and SSB segments centered at 3550 and 3750 respectively. The phasing is using a Collins Hybrid network. At resonance, the dump load power is approximately 5 watts with 1500 watts forward. A second four square array is available for 40 meters to augment the existing beam. Equipment Current station equipment consists of five operating positions. Four of the operating positions are modern technology and the fifth is an antique radio position. The two modern technology positions have an ICOM-756PROII, an ICOM-756PRO, a Yaesu FT-1000MP, and a TenTec Orion. The first operating position has the Orion and a QRO Technologies HF-2500 with full break in capability. The second operating position has the PROII with several monoband amplifiers.. The third operating position is the forty meter position using a Yaesu FT-1000MP with a monoband amp for 40. The fourth operating position has an ICOM-756PRO with a Drake L-7. The antique position has an R-390A and a Johnson Viking Valiant. The four modern operating positions have computer control, automatic inline filters, and automatic antenna switching. The automatic switching allows either station to change bands automatically with the only operator action required is retuning of the amplifier. The components necessary to do this have been provided by Array Solutions. The components used are a SixPak and the automatic ICE 419A filters. Although either station can be on any band, rotor and phased array control boxes are situated separately in the stations. When not set up for contest operation, all control boxes are located at the first operating position. To allow quick contacts to be made with South American and Caribbean stations, either station can select the KT34A pointed South with a press of a button. This antenna is interlocked so only one station can use it. The first requesting station gets the antenna. Both stations have feedback on availability and acquisition of this antenna. The band plan for contest operation is 160 and 15 meters at position 2; 80 meters at position 1; 20 and 10 meters at position 3; and 40 meters at position 4. VHF/UHF equipment includes an ICOM-271A, Yaesu FT-736R, various transverters, commercial and home brew amplifiers, antenna mounted pre-amps and home brew switching systems. AC Power to the shacks consists of a 100 Amp drop for both rooms. Each room has two 20 A 230 V outlets, one 30 A 230 V outlet, and two groups of 20 A 117 V outlets. A full 6 transmitter Multi-Multi can be supported, but all transmitters in tune at the same time would exceed the capacity of the main drop. |