Power/SWR meter à la PD0LEW

PWR METER Wishing to replace my good old trusty BIRD 43 Watt-meter, I prospected a little on the Internet and found the description of an open source project for a Watt-meter which corresponded perfectly to my needs.
This is a fork of the version made by TF3LJ, and developed by PD0LEW. A new hardware version was subsequently developed by WA2T. I chose the version with an OLED display, but there are versions with touch-sensitive TFT displays.

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Wintest + skimmer with Perseus SDR

Cw3kHz mini

How to use Wintest and CW skimmer together ?
This procedure describes how to interface WinTest contest logging software, CW Skimmer in link with a Perseus SDR receiver, and a transceiver in a local configuration. "Local" means everything is hosted and connected to a single computer.

Configuration used :

  • Kenwood radio (TS590 or TS850) via CAT (Computer Assisted Transceiver)
  • Perseus SDR receiver
  • CW Skimmer v 2.1 for CW decoding
  • Win-Test v 4.38.1 for logging

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GPSDO software

GPSO pcb

My previous 10 MHz frequency reference having broken down, the question was whether to repair it or move on.
After reflection, I decided to equip myself with a 10 MHz reference disciplined by GPS (GPSDO) in order to obtain the best possible accuracy.
After some research on the Internet, I found ready-made products at affordable prices and some descriptions of amateur achievements.

I chose the option of making the version proposed by DL4ZAO / DL7UKM . On one hand because there is a detailed description (in German) and that the author offered the printed circuit at a correct price, and on the other hand to learn according to the formula " Build and learn ".
The assembly revolves around an Arduino Nano and software is offered by Michael DL7UKM. All the more reason for my choice, now having a good knowledge of this platform.

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CW keyer with memories "à la SOTA"

20210430 100326 During my SOTA activities, I often raged on the fact that the builtin CW keyer in my QRP SW-3B transceiver only had one memory ... It is indeed very practical to have several of them in order to free your hands to do something else such as finishing writing the last QSO on the logbook or making a somewhat specific call. The idea therefore sprouted to produce a CW memory manipulator that would meet the following conditions
  • 3 on the fly programmable memories
  • low power consumption
  • easy battery supplying
  • reduced size
  • easily reproducible

Having already built a prototype of the fabulous K3NG keyer, I decided to use this project by adapting it to my needs.

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USB audio interface

TKNET USB audio completeOur corsican repeater network TKNET uses the Asterisk software for the routing and communication between nodes. In order to digitalize the audio signals and interface them with the repeaters, i developped a small interface board some years ago. It was using a cheap USB audio stick that we modified and plugged on my board.

With time, this solution appeared to be not the best choice for different reasons. So, the idea to build a newer board with an onboard USB audio chip was born.
Being retired, i found the time and mood to develop a new interface board using the same chip CM119A which is a small LQFP-48 case.

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End fed half wave antenna 40/30/20m

20200822 132846For my SOTA activities, i recently bought a QRP transceiver QRP SW-3B, which is a three-band QRP CW only for 40/30/20 m.
So, i needed an antenna that would allow to use these 3 bands in SOTA portable activity.
Already having some experience with the EFHW antenna, i decided to build one for 40/30/20m.
The main advantages of this EFHW antenna are :
- easy to build
- multiband
- needs only one support, can be installed in line, inverted V,  zigzag.
- fed at its extremity, can be directed connected to the transceriver, without any coaxial cable.
- the radiating part is at the center
All these advantages are welcome for portable operations and make this antenna a perfect candidate for SOTA

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K3NG Keyer

This page is just a reminder for me, so i can find the commands i need from everywhere in the world...  ;-) But it can be helpful ...

I've built a K3NG keyer with a small Arduino Pro mini board. I needed minimal functions :
- 3 memories
- a small speaker for the monitor.
- no speed pot.
- no USB interface.
- sleep mode after 1 minute.
- all settings are done in command mode with the paddles.

To be used in the field, the keyer is powered with a 3.7V battery. When in operating mode, the keyer consumes about 4mA, in sleep mode after 1 minutes : 0.1 uA ! No power switch is needed.

The author's Web page : https://blog.radioartisan.com/arduino-cw-keyer/
The software can be downloaded here : https://github.com/k3ng/k3ng_cw_keyer
The K3NG keyer Wiki is available here : https://github.com/k3ng/k3ng_cw_keyer/wiki/


File Keyer_features_and_options (only this lines were uncommented)

File Keyer_settings (Changed only this line)
#define go_to_sleep_inactivity_time 1
#define analog_buttons_number_of_buttons 4


Enter in command mode by pressing the command button
Exit command mode with X command or press the command button

Px - program memory x (1 to 12), or press memory button after command button
Yxxxx - change memory repeat delay to xxxx ms
REPEAT press the memory button and keep it pressed then touch a paddle.
ERASE simply change memory but leave empty

E - Announce speed
W - change speed with LEFT (plus) and RIGHT (minus) paddles.
M - change COMMAND mode speed

F - Change monitor frequency, use paddles for higher or lower frequency
O - toggle Monitor ( cycles through BOOP OFF, short BEEP ON, long BEEP ON only in paddle mode, not memories )

A - Switch to Iambic A mode
B - Switch to Iambic B mode
C - Switch to Single Paddle Mode
D - Switch to Ultimatic mode
G - Switch to Bug mode
T - Tune mode press RIGHT paddle for permanent Tune, LEFT paddle for intermittent Tune

H - Set weighting and dah to dit ratio to defaults
I - TX enable / disable
J -  Dah to dit ratio adjust
K - Toggle Dit and Dah Buffers on and off (Ultimatic Mode)
L -  Adjust weighting
N - Toggle paddle reverse
Z - Autospace On/Off

? sends status
1) Speed in WPM
2) Keyer Mode (A = Iambic A, B = Iambic B, G = Bug, S = Single Paddle, U = Ultimatic)
3) Weighting
4) Dah to Dit Ratio

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Cushcraft traps repairing.

TC trapI used the Cushcraft A3 et A4s yagis and soon or later, problems are appearing..
Here are the results of my investigations and repairing technic, that can be applied to other models and trades as well.
What is described here applies to a A4s triband antenna, but the reasoning can be made for any multi-band yagi or vertical.

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Harmonic calculator

Enter the lowest frequency in MHz for which you want to calculate the harmonics.

The calculator returns the theoretical wavelength (WL) and mechanical lengths for full (ML), half (ML/2), quarter (ML/4) waves.
The shorting factor used is k=0.95.

  F1 H2 H3 H4 H5 H6 H7 H8 H9 H10
WL (m)
ML (m)
ML/2 (m)
ML/4 (m)

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Test equipements
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