I've bought a cheap chinese DC-block on eBay for my spectrum analyser.

Here some measurements using the miniVNAtiny with vna/J:

 Detailed

I've bought some 30dB SMA pads from Huber&Suhner. 

Here some measurements using the miniVNAtiny with vna/J:

 Detailed

Ich habe von **** eine gebrauchte, schaltbare Eichleitung gekauft. Laut Aufschrift stammt sie von **RE Instruments** aus Jülich. Sie dürfe aus der Zeit vor der Jahrtausendwende stammen und ist wohl aus einem HF-Signalgenerator ausgebaut worden.

Based on the work of Makis, SV1AFN i've build a small, stand-alone power meter with a "nice" GUI. This is the second RF head I've received from Makis. Data about the first one can be found here.

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

Here I've collected some configuration stuff for my KiwiSDR.

Today we had a meeting in our local amateur radio club ESSLINGEN P02.The topic for this meeting was WSPR.

Bernd DK9BH was the organizer of this meeting. He has ordered about 10 WSPRlites from SOTABEAMS. 

I had the chance, to do same basic measurements on one of the WSPRlite units.

Last year I've build the cheap Frog Sounds QRP Transceiver. This transceiver has a pretty basic audio section - a simple LM386 audio amplifier with some LC/RC filtering.

Here are the first pictures of my KiwiSDR setup ...

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 :-/

I've finished my second U3s.

Check out my new KiwiSDR running:

http://dl2sba.ddns.net:8073

Ich habe das Leistungsmessmodul von Oliver, DG7XO nachgebaut. Es wurde in zwei Versionen in der cqDL vorgestellt. Oliver hat mir freundlicherweise eine Platine geätzt und den AVR programmiert, so dass nur noch Löten und Mechanik angesagt war...

Test setup

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

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.

My new U3S is online :-)

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: The tap is based on the work of OZ2CPU.

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.

I've created a new firmware for the hamware AT-515 tuner.

Please check a detailled description in this manual (currently German only)

*** The RAW-Mode for the interface is no longer supported ***

Some parts are available at cost price. Please check here.

Für die Anwender von relativ kurzen Antennen auf den Bändern 160m und 80m habe ich die Firmware dahingehend erweitert, dass für 160m bzw. für 80m ein noch freier IO-Port des Mikrocontrollers aktiviert wird.

An diesen Port kann dann über eine geeignete Steuerstufe z.B. ein Relais angeschlossen werden, welches z.B. eine Spule in die Antenne einschleift um dennoch eine Abstimmung mit dem AT-502 zu ermöglichen.

Eine ausführliche Beschreibung ist hier zum Download verfügbar. Ein programmierter Mikrocontroller wird zum Selbstkostenpreis  inklusive Versand in Deutschland für 15€ abgegeben.