I was looking for a RF power module for my APRS beacon project and stumbled upon RF Parts. They are somehow of a niche–oriented online electronic part retailers, specialised on RF and — it seems — mostly on Ham Radio RF parts. I placed my order for two Mitsubishi power RF MOSFET Amplifier Modules and the package arrived with DHL after three days. All way from California. 🙂
Overall I have nothing to complain about. Fast door–to–door delivered as promised, properly packaged. I will probably order more for them, for my future projects. They have some interesting stuff there. Check their website.
Now, some words about the MOSFET RF Power Modules. I ordered two: RA08H1317M and RA30H1317M. Both are RF MOSFET Amplifier Module for 12.5–volt portable radios that operate in the 135– to 175–MHz range. The difference lies in the output power, RA30H1317M being a 30-watt while RA08H1317M is a 8–watt RF MOSFET Amplifier.
The battery can be connected directly to the drain of the enhancement-mode MOSFET transistors which makes both very convenient to use in my current rig, as I have several 12.5–volt power supplies plus some batteries. Both modules are designed for non-linear FM modulation (typically for radar applications), but may also be used for linear modulation by setting the drain quiescent current with the gate voltage and controlling the output power with the input power. A good read on non–linear FM modulation can be found here.
With a minimum gate voltage around 3.5V for RA30H1317M and 2.5V for RA08H1317M, output power and drain current increases substantially. The nominal output power becomes available at 4V/3V (typical) and 5V/3.5V (maximum). At VGG=5V/3.5V, the typical gate current is 1 mA. First value for RA30H1317M, second for RA08H1317M. Below: some pictures of both amplifiers. The bottle cap — internationally–valid reference for size. 🙂
What follows is to use both in my APRS prototype. As today I’m expecting my second delivery, from DigiKey, the APRS project will probably see some progress by the end of this week.