RX antenna - K9AY loops switch with FIXED Rload

Difference between revisions from 2021/03/18 21:39 and 2019/05/07 12:37.
* [PCB Ver. 1 |K9AY fixed Rload version 1]

* [PCB Ver. 2.0 |K9AY fixed Rload version 2.0]

* [PCB Ver. 2.3 |K9AY fixed Rload version 2.3]

!!!Current version 3.1 (last rev 2.2.2019)
Quick Start Guide
*[Youtube videos|https://www.youtube.com/playlist?list=PLDl8rfKoc17R-iJAA1hu1wXwIrVvJ6ro3] - lsn to K9AY
*[K9AY LOOPs design|https://remoteqth.com/wiki/index.php?page=k9ay-design] - more size variants
*[Assembling the KIT|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+FIXED+Rload&action#Assembling_KIT]
*[Schematic diagram|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+FIXED+Rload&action#Schematic_diagram]
*[Common-mode coax choke|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+FIXED+Rload&action#Common_mode_coax_choke]
*[Example of controller|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+FIXED+Rload&action#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.


!!Schematic diagram

* [bigger schematic diagram - version 3.1|https://remoteqth.com/img/ZAW-WIKI/K9AY_FIX/sch.png]

- version 3.1

!!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


- 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
* '''{.redka#id color: #f23f37; font-size: 200%}⚠{/} 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
* '''{.redka#id color: #f23f37; font-size: 200%}⚠{/} 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.


!!Common-mode coax choke
- choke measurements
* [OK2ZAW.com Blog|https://ok2zaw.blogspot.com/2016/06/common-mode-current-choke-for-rx-cables.html]

!!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

!!Example of controller

* [bigger schematic|https://remoteqth.com/img/ZAW-WIKI/K9AY_FIX/ovl.png]
- 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|https://remoteqth.com/wiki/index.php?page=k9ay-design].
* [MMANA file of my small design for 160 and 80m|https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/mmana/K9AY_ZAW_160+80.maa]

!!K9AY loops - external links.

* [Tom N5EG: Some Observations on the K9AY Receive Directional Antenna|https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/ext/Observations_on_K9AY_receive_antenna.pdf]