The MacTenna SB20-10 Simple Beam antenna.
The MacTenna "Simple Beam"
A new paradigm in directional antennas
The MacTenna "Simple Beam" uses a patented switching technology to change the resonant frequency of a 3 element Yagi antenna. Band changing is nearly instantaneous and is accomplished without the use of motors, mechanisms, or control cables.
The control signals to the "Simple Beam" are sent over the coaxial feed line. The antenna band is selected by a small controller located at the operating position. Because the "Simple Beam" is a wide spaced 50 Ohm design, there is no need to continuously change the element lengths as the operating frequency is changed. This eliminates the need for a serial communication link between the the rig and the antenna controller as is required with close spaced, narrow bandwidth, motorized antennas. This means that the "Simple Beam" will work with all radios made in the past, present, or in the future.
The "Simple Beam" provides superior perfomance compared to close spaced, motorized beams as well as many multi band beams with up to 12 elements. No traps or matching networks are required with the "Simple Beam". We call it the "Simple Beam" beacause it is simple.
The MacTenna SB20-10 Simple Beam antenna with SB6-2 option.
6M and 2M
The "Simple Beam" covers 10M, 12M, 15M, 17M, and 20M. The SB6/2 option allows coverage of the 6M and 2M bands with optional stacked elements, using the same controller and feed line. The optional 6M and 2M arrays can provide higher gain than other highly compromised multi band designs. The user supplied 2M antenna can be a multi element Yagi or a verticle.
The SB6-2 option consists of a larger junction box on the SB20-10 with 2 additional S0-239 connectors. Internal relays connect the feed line to the Simple Beam, the 6M beam, or the 2M antenna (beam or verticle.) This means that only one coax (the main feed line) needs to be routed around the rotator.
LED Indicator Option
The LED indicator option allows verification of correct operation from the ground. LEDs are placed on each switching module. The LEDs can be seen through the fiberglass elements at night. Red LEDs indicate 10M, 15M, and 20M. White LEDs indicate 12M and 17M.
The MacTenna MT-CR1 Antenna controller.
Controller
The MT-CR1 antenna system controller is used to select the operating band of the "Simple Beam". This controller can also be used with the MacTenna wire dipoles to cover 30M, 40M, 60M, 80M, and 160M.
SB20-10 Specifications
| Gain | Free space gains 8 dbi or better (refer to 50 feet and 74 feet EZNEC plots) |
|---|---|
| SWR | Less than 1.7:1 on all bands (Refer to SWR curves) |
| Power | Full legal limit - 1500W PEP (tested to 2400W) |
| Boom length | 20 feet 6 inches (6.25 meters) |
| Longest element | 34 feet 8 inches (10.56 meters) |
| Turning redius | 20 feet 1 inch (6.12 meters) |
| Weight | 50.5 pounds (22.95 kg) |
| Effective area | 6.8 square feet (.63 square meters) |
| (Corrected for cylindrical shape) | |
| Wind speed | 100 mph (160 kilometers per hour) |
Prices
| SB20-10 | 3 element, 5 band Simple Beam | $ 995.00 |
|---|---|---|
| LED20-10 | Optional LED indicators on swithching modules | $ 36.00 |
| SB6-2 | 6M and 2M beam selection option | $ 89.00 |
| (User supplied beams) | ||
| MT-CR1 | Antenna Controller | $ 99.00 |
| MT-32PC | Controller power cable | $ 12.95 |
| (Connects controller to rig 12V supply and injector) | ||
| MT-IR1 | Injector (Places control signals on feed line) | $ 29.95 |