K9AY simply loops switch
The K9AY is terminated loop. It consists of a wire loop of any convenient shape (diamond, delta, etc), hung from a single support and with a ground rod at the bottom. A 9:1 impedance-matching transformer is connected from one end of the loop to the ground and terminating resistor is connected the other end of the loop to the ground. This antenna is directional. Favoring signals are arriving from the feed point end. There, with the two loops, you can switch between four directions. You can also change the antenna far field by changing the RLOAD (RTERM) of the loop.
Main functions:
- Lower noise RX antenna
- Broadband 0,2 MHz to 30 MHz
- 4 directions by about 110 deg.
- Needs small room
- Great for portable operations
- 50/75 ohm feed line version More
- Good for phasing more pieces into the array
- ONE versions
- Variable and Fixed load resistor - by the Jumper on PCB
- ONLY FEEDER! WITHOUT CONTROLLER! This controller could be use.
- Common-mode coax choke icluded.
- High voltage electrostatic protection with neon lamps.
- High power IN/OUT protection with PTC.
- Controlled by DC voltage (external wires) or AC/DC voltage over the coax feed line. More
- Variable terminator resistance (Rload) also by external DC voltage. More
- Stainless connections screws.
- Quality PTFE SO-239 connector.
- UV stable plastic box. (please, protect it against the snow and water)
- Size 10x10 cm (feeder).
- Available as
- Assembled and tested
Parameters:
- RX antenna - Gain depends on loop size
- Four directions by about 110 degrees
- F/B depends on loop size and construction
- You can find more design hints at this link
- Fixed or Variable termination resistor
- Feed line impedance 50 or 75 Ohm
- Common-mode choke isolation more than 30 dB
- Current protection > 100mA and Voltage protection > 65V
- Control AC/DC voltage 11 - 14 V
- Control AC/DC current < 200 mA
- Rload voltage DC about 1,5 to 6 V and 30 mA
Usage:
- RX antenna designed for FOUR directiond
- Small design
- Ideal for portable operation
- Noise source antenna for QRM eliminator
You may be also interested in K9AY ONE direction
You may be also interested in K9AY++ antenna system
Download
| K9AY | ||||
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| Manual in WiKi - THIS version | WiKi manual | |||
| Manual in WiKi - OLDer version | WiKi manual | |||
| Antenna loop design examples | WiKi loop design | |||
| YOUTUBE videos | YouTube | |||
| NEW SMD version 4.0 | schematic  |
board  |
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| OLD - rev 3.1 | variable.sch  |
pcb  |
eagle670 | |
| CONTROLLER DC example | DC controller example |
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| CONTROLLER ACDC example | AC/DC controller example |
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We believe open source is a better way of doing things. View and download the Shield Schematic and PCB Kicad/Eagle CAD files, LibreCAD .DXF, or Inkscape .SVG files. The hardware designs are released under the Attribution-NonCommercial 2.0 Generic |
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Users implementation photos
 by F1SRC |
 PD9X |
 PD9X |
 PD9X |
