144 MHz particulars

Antenna 1: 4 X 17 element yagis @136 ft. 20 dBd gain

Antenna 2: 16 X 5 element yagis stacked vertically, aimed at 230 degrees. 20 dBd gain

Antenna 3: 4 X 6 element yagis stacked vertically and aimed Northeast. 16.8 dBd gain. (2007)

Receiver: Ten Tec OMNI V with added INRAD filters.

Transverter: DEMI 144-28 20 watt transverter with Teletek commercial solid state amplifier.

PA: Home brew Triode amplifier, W6PO design, 1200-1500 watts output

The 144 MHz LVA consists of 16 five element yagis all stacked vertically on one leg of the 130 ft Rohn 45 144 MHz tower. They are all aimed at about 230 degrees, and, with a -3 dB beam width of 57 degrees, provides good coverage over about 90 degrees of azimuth. The gain of the array is about 11 dBd at plus or minus 45 degrees of the boresight heading. ( 185 to 275 degrees!!) This covers a large portion of the activity centers in the Northeast including Boston, Providence, RI, Hartford, New York City, Philly, Albany, and even Toronto! The above picture shows the horizon due South. Above the LVA is an array of 17 element yagis in a large H frame. The rotator is a Prosistel PST-61. It replaced a Hy Gain T2X rotor that was stripped out during high winds on the old 144 tower, which was a 90 ft Rohn 55 right next to the operating shack. The LVA provides about the same amount of gain as the high gain quad array on top of the tower. The top quad array is fully rotatable, and has a narrow beamwidth of about 11 or 12 degrees. The new 130 ft tower is about 235 feet away from the shack and off to the South. The main feedline is a 365 ft run of 1 5/8" coax. There is no preamp. Losses in the feedline are just under 1 dB. The tower base is located about 860 ft above sea level. The hill visible just to the left of the tower, and below the horizon, is about 750 ft asl. Garrison Hill in Dover, NH is visible beyond that. On a clear day, you can see the ocean about 27 or 28 miles away.

Another view of the 144 MHz LVA. The small bright buildings visible to the right of the tower, are in Rochester, NH, about eight miles away.

Telephoto view to the South from the 144 MHz tower, showing the Route 95 bridge at Kittery and Portsmouth, NH. The smoke to the right is from a power plant in Newington, NH. The tanks and structures just to the left of the 95 bridge are at the Kittery/Portsmouth Navy Yard. It is interesting to note, that while the Route 95 bridge over the Piscataqua River is a huge one, and 27 miles away, it is still below the horizon when viewed from the tower here. On a clearer day, the ocean and the horizon is visible just above the bridge.

This is the 144 MHz operating position. The operator is Pete, K9PW. The picture was taken just before the start of the September 2006 VHF Contest. Hopefully that will explain why Pete has four laptop computers there. I think he was programming SSB voice messages and setting up some needed files for Writelog, our logging program. Visible in the photo is the OMNI V exciter. Above the OMNI is an MFJ CW keyer and assorted rotor control boxes and some 2M FM gear. A WSJT computer is to the right of the FM gear. The 144 MHz receive line is heavily RF filtered, and one of several filters is visible on the left side of the operating table next to the 19" relay rack cabinet. The 144 MHz 8877 PA is just visible in the rack behind Pete's back.

K1NKR operating at the 144 chair in September 2005. N2EOC is visible straining to hear a new grid on 50 MHz in the background. Note the air hoses behind the equipment rack. These hoses bring cool air in from the outdoors, and exhaust hot air from the six and two meter amps back outside, in an effort to keep the room cool.

The operating positions are all networked together with a system of conduits and "CAT V" LAN cables. A large router is installed in a metal box housing for shielding. It distributes the network to each of four VHF bands, three microwave positions, two WSJT locations, and a server. Timing for the server is obtained from a GPS receiver on site, which is then routed to all of the laptops on the network. This ensures that our logging times are all the same, and our WSJT skeds are properly timed. The logging program is Writelog, and it seems to run fine in a network configuration. All the operating positions are plugged into the computer for frequency control. It is very nice to see what frequency everyone is on, while trying to pass QSOs between bands. We also use the gab line over the network to set up skeds on other bands as well. The timing issue was a critical thing, as there is no permanent AC power here, and no internet connection. The shack is a good half mile from the house and road.