Monday, December 28, 2015 IP remote hardware switch, based on Arduino

Intuitive remote control switching contains of two devices - controller and relay box - communicate via ethernet.
Suitably for realtime remote devices control, such as receiving antennas, power on/off for any devices, PTT, ...

Main functions:

  • 16 inputs:
    • 11 positions rotary switch,
    • 4 independent on/off switches with LED indication,
    • 1 press button.
  • 16 relay outputs:
    • 0,5A/125VAC, 1A/24VDC,
    • each output is signalised by own LED,
    • 1-11 with common line input.
  • TCP232 ethernet module configurable over network with windows software.
  • Settings in arduino source code.
  • Very low TCP bandwidth, only several units of bytes per second.
  • 1 to 11 outputs are protected as single out (antenna switching).
  • Network latency (delay) is indicated by LINKED LED. Latency is the same as LED off time.
  • Relay parking to define output (default 11), after network unavailable with preset delay. Typically used for grounded TRX input.
  • One control box is able to control up to eleven relay boards - CFG button reconfigure chip and redirect network (more in firmware configuration).
  • Open Arduino platform allows you to customize firmware.
  • 5V power voltage from USB mini plug.
  • Size: control 12x6x9cm, relay 22x3x7cm.
  • Weight: control 210g, relay 270g.

Saturday, December 26, 2015

10m 4x6el G0KSC H-frame stack - HD video

Please enjoy HD video of our 10m stack building...

Wednesday, December 23, 2015

Hybrid Low Pass filter,  part 1

   Thanks to Mikael SJ2W I started to play with hybrid LP filters. Why? Because it is easy design, high power ready, low insert loss and UFB notch. 

   What is it about... There are two coax stub filters, lambda/4 on notch frequency and inductor between. The stubs work as capacitor in the classic PI LP filter design. Look at the results:

Hybrid LP filter for 20m, notch on 10m:

Design: 2x coax abt 2,2m H1000, L is 4,5turns on 30mm

 Hybrid LP filter for 40m, notch on 20m:

Design: 2x coax abt 4.5m H1000, L is 7turns on 30mm

Thursday, November 12, 2015


Ayutthaya, HS

Yangon, XZ

Ngwesaung, XZ

Kin Pun, XZ

And more at :

Monday, November 9, 2015

Another nice weekend at QTH full of work :)

Just a few photos from this weekend. Thanks to Slavek OK1CU, Jarda OK1XUB and Pavel OK1MU. Now we do have QTH more nice :)

We also rotated with our H-frame stack for 10m for the first time! All works :)

Photos from 10m H-frame stack

Nice pipe :)

Sunday, November 1, 2015

"beautifying" OL7M QTH and 80m dipole 4-SQ

   We spent this weekend with the QTH beautifying :) Nice work in the sunny weather. I also needed to do some rests before the snow. So Sloping dipoles for 80m are back on TWR with 75 Ohm coaxes and prototype of my 4-SQ hybrid (TK5EP design).


One special photo for Zdeno OK2ZW, Pavel OK1MU is working with the smile on face 

 Slavek OK1CU and Martin OK1UGA

Measuring 4-SQ / base for the new tower

Mushrooms growing at QTH :) We are still alive!!! :D

 20m TWR with 4-SQ dipoles for 80m