RX antenna - K9AY loops switch with FIXED Rload

Current version 3.1

Assembled KIT

All parts you need - KIT

The drill drawing

Paste the drawing on the box and fix it with some tape.

Schematic diagram

• bigger schematic diagram - version 3.1

- version 3.1

Insert rest parts

chooce the control way...

- By the jumper JP2 you can select controlling over coax or DC voltage on connector X3

TRANSFORMERS winding - very important thing!

• for 50 ohm coax feed line : 2 turns on primar (coax) and 6 turns on secondar side (loop)
• for 75 ohm coax feed line : 2 turns on primar (coax) and 5 turns on secondar side (loop)

- In version 2.3 and higher, you can select Coax impedance by jumper JP3.

- Transformer should have 5 + 1 turns.

Common-mode coax choke

- choke measurements

• OK2ZAW.com Blog

Wind the coax

- Wind the coax as is on the picture, there should be 7 or 8 turns.

- fix it by one binder and use second one to fix choke to the PCB

Solder the coax

KIT - all parts assembled.

Example of controller.

• bigger schematic

- Injector to coax line:

- direction controller

K9AY loops design example.

• It is VERY recomended to place K9AY loop antenna as far as possible from metal towers, antennas and wires. This hepls to obtain better paramaters of antenna ( directivity and noise )
• K9AY Loop design page.
• MMANA file of my small design for 160 and 80m

K9AY loops - external links.

• Tom N5EG: Some Observations on the K9AY Receive Directional Antenna