I've build the original QRP-labs U3S from stock. Means the supplied crystal on the PLL-based synthesiser-board.

This configuration is basically working up to 20m with a lot amount of drift, but you will get many decodes on wsprnet.org. On 6m you can also get spots - once a day :-/

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Kategorie: WSPR

Some times ago, I found for me a solution, how to handle the unstable readings from the ADC. I've described it in this post.

In the meantime, some HAMs also build the RF powermeter based on the work of Makis, SV1AFN and myself. One if these HAMs, PA3AXA Rens, digged a little bit deeper and analysed the problem in detail. Here his description.

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Kategorie: RF Powermeter

With the firmware version 1.8.1 there are some minor enhancements:

  • Offset value is displayed on main screen. "O" at the end of the unit is removed
  • Waveform display also correct when offset is enabled

Here are the required files:

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Kategorie: RF Powermeter

My current working conditions for SOTA are:

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Kategorie: SOTA

Ich habe die Firmware für die Hamware Tuner um den Yaesu FT890 erweitert.

In Verbindung mit dem Logbuchprogramm UCXLog folgt der Tuner automatisch der eingestellten Frequenz.

Nähere Infos sind hier zu finden.

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Kategorie: hamware

The Nextion display needs the content defined in the file PowerMeter.HMI. You can either upload it with the Nextion editor via a serial link to the display or you can copy the TFT file to an SD card and put this into the socket on the Nextion display.

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Kategorie: RF Powermeter

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.

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Kategorie: Power supply

I've read the PA bias study from Hans and tried to tweak the PA of my U3S for optimum harmonics suppression etc. The spectrum is measured using an SIGLENT SSA3021X analyzer. The power is measured using a 40dB tap and a cheap 20w Dummyload from Diamond: ATT The tap is based on the work of OZ2CPU.

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Kategorie: WSPR

With the firmware version 1.8.0 I've introduce the capability to display also the input power in Watt instead of dBm. Simply tap on the unit field on the display to toggle between dBm and Watt.

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Kategorie: RF Powermeter

I've build a simple distribution amplifier for my GPSDO.

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Kategorie: GPSDO

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!.

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Kategorie: QRP

Since last weekend a new QRP transceiver joined my shack V1 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.

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Kategorie: QRP

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

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Kategorie: QRP

Here you can find the last spots for DL2SBA on each band within the last day and the all time farest spots.

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Kategorie: WSPR

  Live data from my WSPR feed

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Kategorie: WSPR

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.

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Kategorie: WSPR

I've introduced with the firmware version 1.7.1 a complexity to this project which may not be suitable to all users.

WIth the firmware version 1.7.2 I've reduced the complexity by removing the remote configuration utilities.

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Kategorie: RF Powermeter

In this post I describe in details, how you can create the calibration factors for k0 ... k3 based on raw data measured with the power sensor.

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Kategorie: RF Powermeter

If you are using my powermeter software in conjunction with Maki's module and have a unstable readings or sporadic extrem value changes, this is a problem of the CS pin. It may be a grounding issue - Makis is currently analysing the problem.

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Kategorie: RF Powermeter

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.

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Kategorie: RF Powermeter

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!

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Kategorie: WSPR

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 Wspr V3

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Kategorie: WSPR

My new U3S is online :-)

U3S 2

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Kategorie: WSPR

Measurement of the signal quality of QRP-Labs U3s with low-pass filters.Transmitter output is fed into a homemade 40dB power pad. The spectrum is measured using an SIGLENT SSA3021X analyzer.
The bias voltage was about 2.6VDC and the PA voltage was abt. 7VDC.

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Kategorie: WSPR

Test setup

MA1

I made some measurements using my miniVNApro with a simple test fixture fittig the QRP labs lowpass filters.

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Kategorie: WSPR

In case you've bricked the UNO bootloader or even the USB bootloader in the ATMEGA16U2, this may help ...

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Kategorie: Arduino

I've added a new feature to the firmware release 1.5.0 V1.5 1 - power offset V1.5 3.

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Kategorie: RF Powermeter

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.

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Kategorie: RF Powermeter

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.PowerDev

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Kategorie: RF Powermeter

Based on the code  from Makis, SV1AFN I have created a small library to access the AD7887 ADC converter. The library is pretty simple to use.

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Kategorie: Arduino

2014 CW (Morse Telegraphy) was added to the German Nationwide Inventory of Intangible Cultural Heritage.

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