Receive Short Element Active Vertical Antenna
We have two low-band receive systems at our station:
These antenna systems use short active vertical antennas in various combinations to create directional receive antennas for the low bands (80m and 160m).
Receive Short Element Preamplifier
We recently upgraded these antennas to the latest Short Active Vertical Antennas from DX Engineering. The upgraded elements feature internally settable gain for any size antenna or ambient noise environment and include an LED, which indicates when an element is active.
Receive Feedline Choke
We also upgraded the Receive Feedline Chokes on both antenna systems as well.
New NCC-2 Receive Phasing Controller
NCC-2 Receive Antenna Phasing Controller
We also upgraded our two-element phased receive system to use the DXengineering NCC-2 Phasing Controller. The NCC-2 variable phasing controllers combine the 300 kHz- 30MHz received signals from two dedicated active short vertical receive antennas. Combining signals from two stationary antennas physically spaced 1/10 to 1/2 wavelength apart creates an array pattern with signal peaks and dips called nulls. Adjusting the NCC-2 Phase and Balance controls has the effect of electronically rotating or steering that pattern. Steering the null direction to significantly weaken a local or distant interfering signal or noise is known as “Noise Cancelling. The NCC-2 Noise Cancelling Controller can enhance the reception of weak signals from non-null directions. This “reverse-beam” capability on AM Broadcast through HF radio frequencies can benefit many types of AM DX and SWL receiving and ham radio operating.
We installed the following options in our NCC-2:
- 160m High-Pass Receive Filter Set DXE-NCC2FL-HP160
- Receive Preamplifier Plug-in Module Plug-in Modules DXE-RPA-2-PM
- 75 to 50 Ohm Impedance Transformer Plug-in Modules DXE-IT-PM
Receive Array Control And Sequencer
We also built a variation of the Receive Array Sequencer using a microHam control box. This sequencer system properly sequences the NCC-2 and the associated antennas whenever any radio in our station transmits on a band that might damage the sensitive receive antennas. This system is described in more detail here.
NCC-2 Performance
80m Opening to China
The NCC-2 and Antenna Elements upgrades have noticeably improved the performance of our low-band receive antenna systems. Shortly after the upgrades were completed in December 2024, I worked BA7IO in China on 80m using the NCC-2 and the upgraded Active Vertical Receive Antennas. This was a difficult contact, given that we are near the peak of the current solar cycle.
Want To Learn More?
We did a guest spot on DXengineering’s weekly video broadcast about the project. You can view the video here.
Fred, AB1OC
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