DX Engineering DXE-AVA-3 Active Matching Units

DX Engineering DXE-AVA-3 Active Matching Units are state-of-the-art broadband receive RF operational amplifiers that work as a high impedance buffer between a short antenna element of 6 to 24 feet and an economical 75 ohm feedline. The AVA-3 and a short element are intended to be mounted on a ground rod at ground level in a clear area away from all metal, towers and other antennas. The DXE-AVA-3 Active Matching Unit is the heart of the new line of DX Engineering Receive Short Element Active Vertical Antennas, DXE-RSEAV-1. Compared to large antennas, this approach dramatically improves receiving signal-to-noise performance.

DXE-AVA-3 Active Matching Units achieve unparalleled weak signal reception across the radio frequency range from 40 kHz* to 30 MHz. They may be used for VLF through HF reception with short metal or wire elements that measure from less than 6 feet up to 24 feet. The DXE-AVA-3 has a myriad of broadband receive RF applications as a high impedance buffer between a physically small antenna element, the 75 ohm coaxial cable and the receiver.

The AVA-3 Active Matching Unit provides these features and benefits:

• Ultimate frequency coverage of 40 kHz* to 30 MHz for VLF through HF (including the 2200m and 630m Amateur bands)

• High Third Order Intercept (TOI) Performance +39dBm for superior strong signal handling equal to top transceivers

• Consistent unit to unit gain and phase for greatly improved array performance

• Virtually Flat Gain (+/-0.4 dBm) across the entire frequency range

• Internally settable gain (default -6, 0, or +6 dBm) for different ambient noise locations and element sizes

• Direct DC via second F connector – internal settable choice for separate DC and RF coaxial cables for best performance, or standard Bias Tee DC on the RF coax for most users

• Each DXE-AVA-3 Active Matching Unit operates on 12 -15 VDC at 25mA

• Element is grounded when power is removed

• 75 ohm F connectors support field serviceable RG-6 Quad Shield suitable up to 1,000 feet for VLF through HF

*Frequency coverage below 100 kHz requires Direct DC on a separate DC only coaxial cable.

The DXE-AVA-3 features internal jumper selection of relative gain settings, with the factory default of -6dB, as well as 0dB and +6dB settings, to match the ambient noise conditions for the antenna location, and to adjust for the size of the antenna element to be used. As a rule of thumb, always use the lowest gain setting with the minimum discernible ambient background noise that is at or just above the noise floor of the receiver. This setting will allow the greatest signal-to-noise improvement for all signals, especially weak signals.

The versatility of the AVA-3 also includes the option of using the Direct DC F connector for installations where the use of the AVA-3 internal Bias Tee, is undesirable. NOTE: For optimal receive performance, especially on VLF frequencies from 40 to 200 kHz, Direct DC is required. For installations where the DC is intended to applied at all times for uninterrupted reception, such as for skimmers and remote receivers, Direct DC via the separate coax to the “OPTIONAL DC POWER” input is recommended, so the “75 Ω OUTPUT” coax carries only received RF. However, for average Amateur installations using 1.8 to 30 MHz at intermittent operation, where the DC supply is normally turned off, standard internal bias tee DC over the RF coax is perfectly acceptable.

The DXE-AVA-3 Active Matching Unit is at the heart of the new line of DX Engineering Receive Short Element Active Vertical Antennas. DXE-RSEAV-1 antennas include the AVA-3, a high quality three-section 8.5 ft. (2.6m) aluminum tubing whip, clamps and mounting plate. DXE-RSEAV-1 multiples of 2, 4 and 8 are available for receive arrays. When deployed in the appropriate location, they provide significantly better weak signal reception than other actives or full size transmit-capable antennas, with substantially reduced noise and spurious signal interference. Class leading performance makes the DXE-AVA-3 Active Matching Units and DXE-RSEAV-1 Receive Short Element Active Vertical Antennas the best choice on the market for reception of long distance AM broadcast, Medium Wave and Shortwave Listening (SWL), and for DXing, contesting, listening for signals on the new VLF and LF bands, and for everyday operations in Amateur Radio.