RX antenna - K9AY loops switch with FIXED Rload
Current version 3.1 (last rev 2.2.2019)
Quick Start Guide
- Youtube videos - lsn to K9AY
- K9AY LOOPs design - more size variants
- Assembling the KIT
- Schematic diagram
- Jumpers
- Common-mode coax choke
- Example of controller
Assembling KIT
All parts you need - KIT
The drill drawing
Paste the drawing on the box and fix it with some tape.
Insert rest parts
- small yellow Caps 104 = 100nF 3x
- yellow small polyester capacitor 104 1x
- bigger yellow PTC - EX10 1x
- black inductor 1x
- two blue Varistors
- two small resistors 1k
- two LEDs - pay attention to polarity! Long leg is +++
- Rload 2W resistor on the bottom side
Jumpers
- By the jumper JP3 you can select 50 or 75 Ohm coax output
- Jumper JP1 must be short if you want to control direction over coax
- ⚠ NOTE: If you use external DC control, please disconnect JP1. If not, you will have DC voltage on the coax!
- By the jumper JP2 you can select controlling over coax or DC voltage on connector X3
- ⚠ NOTE: If you use external DC control, please disconnect JP1. If not, you will have DC voltage on the coax!
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.
Wind the coax
- Common mode current choke construction
- Wind 4 turns on one side than cross to another side of cores and wind rest turns.
Solder the coax
KIT - all parts assembled.
- sri photo of older PCB version
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
