RX antenna - K9AY loops switch with remotly VARIABLE Rload

Difference between revisions from 2021/03/18 21:39 and 2019/05/07 12:36.
* [PCB Ver. 1 |K9AY version 1]

* [PCB Ver. 2.0 |K9AY version 2.0]

* [PCB Ver. 2.3 |K9AY version 2.3]


!!!Current version 3.1 - Variable Rload with FIXed JUMPER
------------------------------------------------------------
!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 KIT|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+remotly+VARIABLE+Rload&action#Assembling_KIT]
*[Schematic diagram|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+remotly+VARIABLE+Rload&action#Schematic_diagram]
*[Jumpers|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+remotly+VARIABLE+Rload&action#Jumpers]
*[Common-mode coax choke|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+remotly+VARIABLE+Rload&action#Common_mode_coax_choke]
*[Example of controller|https://remoteqth.com/wiki/index.php?page=RX+antenna+-+K9AY+loops+switch+with+remotly+VARIABLE+Rload&action#Example_of_controller]




!!Assembling KIT
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/8.jpg|noborder]

!!Why variable Rload???
- look at far field plots from MMANA
* [bigger MMANA far field|https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/mmana_vac_big.png]

[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/mmana_vac.png|noborder]

!!The drill drawing
Paste the drawing on the box and fix it with some tape.
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/6.jpg|noborder]

[https://remoteqth.com/img/ZAW-WIKI/Bi-Dir_1out/10.jpg|noborder]

!!Schematic diagram
* [bigger schematic diagram Version 3.1|https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/sch3-1.png]

- Schematic Version 3.1
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/sch3-1S.png|noborder]


!!Rload resistors for VARIABLE and FIXED
* There are TWO resistors. First 1k2 in paraller to VAC and second 750 R as option for FIXed Rload - see below.
* NOTE! Solder 1k2 resistor on the botom side after the protection diodes!
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/bb_web.jpg|noborder]
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/cc_web.jpg|noborder]

!!Voltage controlled resistor
* VTL5C1 - [DataSheet|https://www.google.cz/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjMpLusgpLOAhXI0xoKHdlDAeAQFgggMAA&url=http%3A%2F%2Fwww.excelitas.com%2Fdownloads%2Fdts_vtl5c1c2.pdf&usg=AFQjCNGXZnFAn7xDgRNRpZsmB9BF_ncS3w&sig2=PtA98Nt0fHi9Rc7qF0-DBA]
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/1.jpg|noborder]

- insert VAC plus to plus - check package
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/2.jpg|noborder]

!!Inductors
- there are two resistors. Both are 100uH. But L1 is for higher current. L1 is black axial inructor. L2 is small resistor size green one.
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/d_web.jpg|noborder]

!!Capacitors
- solder 100nF YELLOW capacitors
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/ff_web.jpg|noborder]
- some older versions do have 470nF capacitor
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/401.jpg|noborder]

!!Protection diodes
- solder 6 + 6 diodes
- these diodes protect Rload resistor against high power, electrostatic etc.
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/402.jpg|noborder]

[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/403.jpg|noborder]

!!Insert PTC 100mA and rest parts
- PTC EX10
- Varistors
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/404.jpg|noborder]
- rest parts
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/405.jpg|noborder]

!!Jumpers
- By the jumper JP3 you can select 50 or 75 Ohm coax output
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/jmp3-1-imp.png|noborder]
- 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!'''

[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/jmp3-1-coax.png|noborder]
- 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!'''
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/jmp3-1-way.png|noborder]
!!FIXed Rload !
- You can use this VARiable Rload KIT as FIXed one.
- Than you need only coax cable to control direction etc
- Conect JP4 to SHORT - and you have fixed Rload abt 460 Ohm / 4W
-  DO NOT APPLY ANY VOLTAGE TO VTL!
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/jmp3-1-fix.png|noborder]




!!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.
[https://remoteqth.com/img/ZAW-WIKI/trafo/transformer_winding_5-1_850.jpg|noborder]

[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/v2.3/2.jpg|noborder]


!!Common mode coax choke
- choke measurements
* [OK2ZAW.com Blog|https://ok2zaw.blogspot.com/2016/06/common-mode-current-choke-for-rx-cables.html]
[https://remoteqth.com/img/ZAW-WIKI/Bi-Dir_1out/40.jpg|noborder]

!!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.

[https://remoteqth.com/img/ZAW-WIKI/4-way/5.jpg|noborder]
[https://remoteqth.com/img/ZAW-WIKI/4-way/6.jpg|noborder]
[https://remoteqth.com/img/ZAW-WIKI/4-way/7.jpg|noborder]


!!Solder the coax 
[https://remoteqth.com/img/ZAW-WIKI/Bi-Dir_1out/30.jpg|noborder]


[https://remoteqth.com/img/ZAW-WIKI/Bi-Dir_1out/31.jpg|noborder]


!!KIT - all parts assembled.
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/7.jpg|noborder]

!!Example of controller

* [bigger schematic|https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/ctrl_big.png]
- Injector to coax line:
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/inj.png|noborder]
- direction and VAC Rload controller
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/ctrl_small.png|noborder]



!!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]
[https://remoteqth.com/img/ZAW-WIKI/K9AY_VAC/mmana/ant.png|noborder]


!!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]