I've developed a new firmware for my RF Powermeter. In this firmware, the user can now program for six calibration points the factors for the polynimial regression functions.

Therefor I've developed a JAVA GUI application for downloading these floating point values to the device.

*** CAUTION ***
All stuff described in this post is ONLY running on an Arduino which runs the OptiBoot bootloader. The EEPROM capability of the OptiBoot bootloader is needed for the features of firmware V1.7.1

I described here a way how to flash the OptiBoot loader on an Arduino UNO clone. For this you need an ISP or a second Arduino to act as an ISP.

I've added a new feature to the firmware release 1.5.0 - power offset .

The original library from Dan is not working as expected for me. So I adopted the code a little bit.

You can find the changes below. You can also download "my version" of the library here. Unzip into the Arduino's library folder.

As described here, I've build an RF Powermeter.

The basic firmware is now running. So I started analysing the accuracy of the used meter head.

Inspired by the work of Richard G3CWI from SOTABEAMS and his flight decks for some QRP transceivers, I decided to build a matching one for my ELECRAFT KX3.

Starting point was a clipboard which can be found for some bucks at AMAZON. In the lower section, I can simply secure my log sheets with the strong clip.

My second SOTA activation is done. Monika (DL6SCF) and I made a short hiking trip on the Swabian Alps. On top of the Kornberg we made a stop and started the activation ... unfortunately we have to shut down operation due to a rising thunderstorm.

During a business trip, I took the chance to activate a mountain in the Bavarian low mountains - Kleiner Kulm.

My current working conditions for SOTA are:

• ELECRAFT KX3. With its build in antenna tuner it does a quite remarkable job.
• For the power I use a LiFePO4 battery with 12V 6,6Ah with a build in BMS.
• Microphone for the SSB contacts is the stock-mike from ELECRAFT.
• For CW I use the Palm Pico Paddle.
• Antenna is a HYENDFED 3-band antenna.
• Flight-Deck for KX3
• A 10m fibre pole from DX-Wire - MINI
• Some velcro-straps

I've used one of these cheap switch-mode DC-DC converters (available on eBay for a few bucks) for my WSPR U3S transmitter. Checking the transmitted signal reveals strong spurious emissions. Hints from the QRPLabs group leads me to the cause - the DC-DC converter. Replacing it with a linear LM317 one solves the problem.

I've checked this extremly simple concept for spurious emissions and whether they're compliant with the current regulations ...

Yesterday I've build the FROG SOUNDS 40m CW QRP transceiver.

I've ordered it as a kit from eBay Seller for about €10,- inclusive shipping to DL. The kit arrived well packed after about 15 days in my postbox.

Currently I've done 6 QSOs with the Frog and my dipole antenna.

In 2015 I've build the Frog Sounds QRP transceiver.

This little transceiver still needs improvement:

1. The output is still only 400mW
2. The key-click is horrible - even with the additional audio cw-filter.
3. The suppresion of harmonics is very bad. Check below.

If someone has any ideas how to fix this, please Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein!.

Since last weekend a new QRP transceiver joined my shack I bought her used from a German HAM via the QRPFORUM community. The transceiver is one of the older projects from the DL-QRP-AG but still a neat little transceiver. It is still offered in kit-form from QRP-Project in Berlin.

  Live data from my WSPR feed

Here some analysis of my recorded spots data with my spot data collector. As of today there are 45.000 spots recorded in my database.

I've done some measurements on two RF detectors - one on an older diode detector from ELDITEST and another one on an AD8307 based one from SV1AFN.

My WSPR data collector is now running some days and I started with some basic data analysis.

The power on the bands 60m to 20m is about 100mW!

Inspired from some work found on the Internet and the full functionality of my U3S I've build an automatic spot collector. The spot collector pulls every 5 minutes my spots from WSPRnet.org and puts it into a MYSQL database for later analysis. See the schematic for this setup

Setup