I have the power!

Lets talk about power amplifiers solutions for AO-100

The successful launch and commissioning of the AO-100 has been a real rule-change in the story of amateur satellites. Although foreseeing since the very beginning of Oscars story and classified as “phase 4”, we had to wait for more than five decades to have the very first geo stationary amateur satellite in place and fully available.

But why it’s referred as “phase 4”? Let step back to the origin, when the continuous technological development led the history of amateur radio satellites to be divided into "phases", each of which is characterized by clear objectives and technical or structural characteristics.

The following table includes the distinctive characteristics of each “phase”.




Satellites powered only by batteries with short life dedicated to technology experiments


Satellites of long duration and capable of translating communications (transponder). LEO orbit powered with solar panels


Satellites of long duration with complex communication systems, control and telemetry.

Mostly HEO and Molniya orbits


Satellites in geostationary orbit. The QO-100 is the very first actually been built and launched


Satellites or even space probes capable of interplanetary or lunar missions. Designed

and partially built but never launched


Since its commissioning, the QO-100 demonstrates of being even more sensitive than expected. I personally succeed to run some QSOs with only 400mW and a 10dB horn antenna and I believe this is probably one the most QRP way to use the bird. For a more reliable and comfortable traffic some more ERP is needed. As rule of thumb, it’s preferable to start investing on a good and big antennas, but not always space, cost and other constraint let us reach to the ERP wished in that way. Thus the only chance comes from an higher transmit power.

The market is now plenty of offer of smalls, compact and (often) cheap amplifier modules, mostly intended for WiFi, Cellular, WiMax, ISM and Bluetooth applications. But how do they perform? Which pro and cons? Let see my experience with some of the most popular ones.

An important note prior to moving on: I do not have a certified ISO 17025 radio frequency lab at home, but a “regular” ham one. So, all the figures you will find on the following pages have been measured with my best effort to minimize errors but of course, are not “official laboratory grade” ones.

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