Availability
COMTEK CFC-50X Common Mode Feedline Chokes
COMTEK CFC-50X Common Mode Feedline Chokes are designed to suppress unwanted RF currents on the outside of the shield on coaxial feedlines. These 1:1 inline coaxial feedline chokes are built with fifteen Mix-31 ferrite beads on premium DX Engineering RG-8X coaxial cable, offering improved performance for a wide variety of antenna systems. COM-CFC-50X Key Benefits: • Provides Effective Shield RF Current Suppression from 1.8 to 54 MHz, helping eliminate common mode currents that cause RF feedback and noise inside the feedline. • Consistent and balanced pattern across frequency range: Excellent RF choking isolating the feedpoint prevents current imbalance, which preserves radiation pattern and antenna performance.
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$59.99
COMTEK Current Feedline Chokes
The updated COMTEK CFC-50A 50 ohm Feedline Chokes consist of 75 heavy-duty mix-31 RF choke beads on a length of RG400 PTFE coax terminated at both ends with silver-plated PTFE PL-259/UHF male connectors and the correct length of heat-shrink tubing. COMTEK Current Feedline Chokes ensure that stray RF does not flow on the outside shield of your feedlines. They are typically installed at the antenna feedpoint connection. They may also be used where a long run of feedline leaves a remote antenna switch or a tower. They are also very effective at the shack end of a long run of on-the-ground or above-ground coaxial feedline, to block unwanted RF signals and noise picked up on the shield. These chokes provide excellent common mode impedance and handle up to 5 kW from 1.8 to 54 MHz. These chokes are assembled except for the tubing needs to be installed and heat-shrinked after the choke is positioned as it will be installed.
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$131.49
COMTEK ACB-4 Hybrid Four-Square Systems
COMTEK ACB-4 Hybrid Four-Square Systems are phased array Relay Units and Control Consoles that are affordable, simple to install, and easy to use. A four-square phased array consists of four mono-band resonant elements fed in phase relationships and power ratios that produce a directional cardioid pattern. Four-square arrays offer up to 5 dB of forward gain and fantastic front-to-back rejection over 25 dB! COMTEK ACB-4 Hybrid Four-Square Systems are designed for use with four quarter-wave ground mounted verticals, spaced one-quarter free space wavelength on the side of the square, with complete ground radial systems. Properly installed with quarter-wave 75-ohm phasing feedlines, the Four Square provides an excellent cardioid pattern that is steerable to the four directions of the corners of the four square array. Ground-mounted vertical arrays are easier to build and less costly to maintain than towers and beam antennas. Four-Square arrays are a practical solution for building a high performance directional HF antenna system, especially for Low Band DXing and contesting. Click the "More Details" link for more information on COMTEK ACB-4 Hybrid Four-Square Systems. COMTEK ACB-4 Hybrid Four-Square Relay Units are single-band phasing and relay devices. They are typically in stock for every major HF contesting Amateur band, and for 30 meters. The 60 meter band is available by special order. Four-Square arrays are single band specific, due to antenna spacing and phasing feedline lengths, for proper phasing and patterns. DX Engineering offers a full line of 75 ohm Phasing and 50 ohm feedline coaxial cables, control cables, antennas and accessories for your phased-array installation. The COMTEK ACB Series Hybrid Units also require a good 50 ohm, non-inductive dummy load. The electronically and mechanically improved COMTEK ACB-4 Hybrid Four-Square Systems now include the new COMTEK ACB-4A Four-Square Control Console. Specially designed to be useful as replacements for existing COMTEK ACB Hybrid four-square antenna systems, ACB-4A control consoles now feature a 13.8 VDC input to be easily integrated into all stations, including those that can be run on 12V DC emergency power. Their front panels have four-position rotary switches and four label pads and LEDs to indicate the array directional positions. The COMTEK ACB-4A Four-Square Control Console is ready to control your COMTEK Hybrid Array with low-cost three conductor control cable. COMTEK ACB-4 Hybrid Four-Square Systems include the Hybrid Relay Units with these features: * 2 kW rating for Amateur SSB and CW * 15 amp gold plated contact relays with dust covers * PTFE silver stranded wire over fiberglass tape-wound toroids * Balanced temperature, frequency, and voltage stable capacitors * Double-sided printed circuit board * MOVs for lightning surge protection with RF bypass caps * Brushed aluminum Z-chassis and cover with riveted seams * Mounting clamp included Regardless of the band you choose, COMTEK ACB-4 Hybrid Four-Square Systems from DX Engineering will help you rack up the contacts!
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$569.98
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$709.98