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Some ARRL products and services arrive in the mail, via e-mail or are on the Web. QST, Technical Information Service and late-breaking news are a few examples. Maxim Memorial Station W1AW provides its services via Amateur Radio, however. These primarily include bulletin and code practice transmissions. W1AW's bulletin antennas, therefore, must deliver a strong signal to all parts of the US. The station also is available to licensed HQ visitors. A visiting ham may wish to focus on working a particular region on Earth. Another may want to work satellites or listen in on an Amateur Radio on the International Space Station contact. How many antennas does it take to satisfy all these requirements? Let's take a look at the W1AW antenna farm.
 Left to right--South, Center, Satellite and North towers. |
Perhaps the first visual clue visitors get as they approach ARRL Headquarters is the sight of two beams--20 and 40 meters--at 120 feet, the top of the center tower. The next view is that of all four towers, supporting a complex array of beam antennas. Welcome to the W1AW antenna farm, a group of towers ranging from 60 feet to 120 feet and comprising 27 different antennas.
The Maxim Memorial Station
W1AW--the Maxim Memorial Station, named after League co-founder Hiram Percy Maxim, who had held the W1AW call sign--provides operating positions for use by amateur licensees visiting ARRL. Almost every mode of transmission available to hams is available. Visit ARRLWeb or any issue of QST for the W1AW operating schedule and additional information.
W1AW has transmitters for all bands from 160 meters to UHF. Beam antennas are available for the bands above 80 meters. A complete description of the station will be the subject of a forthcoming installment of this series.
The station also transmits official ARRL bulletins on a regular schedule on CW, SSB and RTTY. Bulletins might include news of FCC decisions, a current emergency, propagation, and DX news. The bulletin antennas are oriented to provide optimal coverage of the continental US.
Cables and Grounding
 In the W1AW basement, copper straps connect electrical and water systems to the shield that bonds all coax feed lines to ground. Coiled cables are delay lines for phasing stacked antennas. |
A proper antenna farm includes the entire system: a good ground system, adequate lightning protection, low-loss feed lines, tower support, and radiating elements. Let's start from the bottom up. A patch panel in the station connects station equipment to the antennas by way of Andrew 50-ohm half-inch hardline for all antennas. Cables exit the patch panel and connect to a large quarter-inch-thick aluminum ground plate in the building's basement. There, the outer shields are bonded to the plate, which is in turn grounded to Earth and to the building's electrical and water systems, using two-inch-wide copper strap.
 Coax emerges at the base of each tower into a box that contains Polyphaser lightning arrestors and is then directed up the tower. |
The plate's function is to act as a backup lightning protector, should the upstream lightning arrestors fail to stop large currents in the cable shields. The cables then exit the building through underground conduit and emerge into a weatherhead box at the base of their respective towers. There they pass through Polyphaser lightning arrestors. The cables continue up the towers to a point very near their respective antennas, where they connect to RG-213 coax to allow a flexible connection to the antennas.
The base of each tower also is grounded. Copper cable--#4 solid--is connected from each leg and attached to its own ground rod, driven into the ground as close as possible to the tower. All connections are treated with Penetrox to retard corrosion.
The Towers
The towers consist of Rohn SSV commercial tower sections. The North Tower is 65 feet high and was made from the top three sections of a 250-foot tower. It's mounted on a concrete base and is self-supporting. It supports five rotating and three fixed antennas, which we'll describe later. Due south--on the other side of the W1AW building--stands the Satellite Tower. At 60 feet, it is the shortest. It's self-supporting and is home to four antennas. In line and to the south is the South Tower--65 feet high. It supports three rotating antennas and one fixed antenna.
Slightly offset to the northwest is the 120-foot Center Tower. It supports two rotating antennas and 10 fixed antennas and is the only guyed tower. Steel cable guys, interrupted by insulators, connect at the 60 and 100-foot levels. The guy wires are embedded in concrete and are protected by a six-foot high fence at their base. Similarly, all the towers are protected at their bases by chain link fence. Three of the fixed antennas at W1AW are dipoles and are supported by these towers. So if you have been keeping a tally, you have noticed that there seems to be more antennas than first reported.
In July 1998 the bottom section of the 120-foot tower was replaced by simply hoisting the entire structure upward with a crane and inserting a new bottom section! This spectacular project was described and pictured on ARRLWeb, September 1, 1998: "W1AW Levitates 120-foot Tower".
The Center Tower was bequeathed to ARRL by a former Michigan Section Manager, Ralph Tetreau, W8FX. The other towers were purchased by ARRL and were part of the major renovation to W1AW undertaken in 1989. See QST, Jun 1988, p 64 and Dec 1988, p 58, for details on the W1AW renovation.
The W1AW Antennas, Tower by Tower
The antennas themselves are the most visually impressive part of the antenna system. All of the antennas are commercially available Amateur Radio antennas and were purchased or donated, with the exception of the 160-meter dipole, the 80-meter Cage dipole and the Frank Witt, AI1H, 80-meter coaxial resonator dipole (QST, Apr 1989, p 22), which were constructed by W1AW Station Manager Joe Carcia, NJ1Q.
ARRL ordered most of the commercial antennas to be built with slightly broader band capability--at the expense of gain--than the usual design offers. This compromise allows visitors to choose any part of the band without having to be overly concerned with high SWR. With the exception of the circular polarized satellite antennas, all the monoband beams are horizontally polarized. As for the antenna matching, almost all antennas use what's known as Cushcraft's Reddi-Match--similar to a regular gamma match. The VHF antennas use T-match.
North Tower Antennas
 Topped by a 49-foot-long nine-element 6-meter beam, the North Tower offers plenty of antenna choices for visiting operators. |
The 65-foot North Tower provides rotary beams on 17, 10, 6 and 2 meters and 70 cm. There is also a 100-1000 MHz discone at the 20-foot level connected to an ICOM R-7000 receiver. Brackets at the 20 and 40-foot levels support two 2-meter vertical AEA Isopole antennas. The tower also supports the center feed point of the AI1H 80-meter Coaxial Resonator dipole, oriented to transmit North-South.
The 17-meter beam is a 3-element Telrex; the 10-meter beam is a 5-element Cushcraft; the 49 foot long, 9-element 6-meter beam is a M2-6M9KWH, which was donated by the manufacturer. The 18-element 2-meter beam is a Cushcraft, as is the 21-element 70-cm Yagi. These are connected to the guest operating positions in the station. One 2-meter AEA Isopole is used for packet cluster and another for APRS. Also, one end of the 80-meter Cage dipole is supported from this tower.
Satellite Tower Antennas
 Visitors choosing to work satellites have 2-meter and 70-cm, 20-element Yagis at their disposal. The tower also functions as the center support for the 80-meter Cage antenna. |
The 60-foot Satellite Tower supports a 20-element 2-meter crossed Yagi and a 15-element 70-cm crossed Yagi. Both are mounted on an az-el rotator and can be remotely controlled to provide left-hand or right-hand polarization. The tower also supports the 80-meter Cage antenna center-feed point at 60 feet. A 22-foot length of RG-213 is wrapped into an 8-turn coil which serves as a choke and balun feed to the Cage. This antenna is oriented to transmit East-West and is primarily used for bulletins. W1AW is collecting reception reports on this antenna. At the 40-foot level an extension arm supports a Rocky Mountain 2-meter and 70-cm J-pole.
South Tower Antennas
 The South Tower. Visitors have their choice of a 12, 15 or 30-meter rotatable beam or a fixed 17-meter beam. |
A 10-foot mast atop the 65-foot South Tower supports 12, 15 and 30-meter three-element rotary beams and is connected to the guest positions in the station. In addition there is a 3-element 17-meter beam in a fixed position--west orientation--for ARRL bulletins. The 12, 15 and 30-meter beams are at the 70, 67 and 65-foot heights, respectively.
Center Tower Antennas
-and-South-Tower2-lrg.jpg) Quite often, the center tower is the first landmark spotted by hams on their way to visit ARRL Headquarters. At 120 feet, it stands well above the local tree line. |
The 120-foot Center Tower has the most complex arrangement of antennas of all the towers and is by far, the tallest. A three-element 20-meter beam and a two-element 40-meter beam rotate together. They are used for the guest-operator positions of W1AW. The 40-meter beam can be phased with another fixed beam mounted at a lower level and is aimed north-northwest. Similarly, the rotatable 20-meter beam can be connected to two more 20-meter beams mounted lower on the tower in fixed orientations to the south-southwest and north-northwest. This interconnection allows coverage of the entire continental US on 20 and 40-meters, or an extremely potent signal in the north-northwesterly and south-southwesterly directions.
Eight fixed beams, two collinear arrays and the center-feed of a 160-meter dipole make up the balance of antennas on this tower. The fixed antennas are primarily used for W1AW bulletins. There is one three-element 10-meter beam; two three-element 15-meter beams--fed in phase; two three-element 20-meter beams--already mentioned; a two-element 30-meter beam--not operational at this time; a two-element 40-meter beam that can be connected to the rotatable 40-meter beam already mentioned; a four-bay vertically mounted 2-meter collinear; a four-bay 222-MHz collinear--for packet transmissions--and the center-feed for the 160-meter inverted-V dipole, which transmits north-south. For a one-page summary of the antennas mentioned in this article, see sidebar, "Guide to the W1AW Antenna Farm".
