Narrowband is much easier. If this is for a jammer or any communications purposes you do not need wideband capability. You did not specify the noise figure requirement of the PA. With degraded NF, a PA can be designed to meet that span and output power. Quote from: radioactive on September 13, , am. In that case what you need is several amplifiers, one for each band.
For 23cm people have had success using the mrfe6s For 13cm there is the AFT23S Here is an article about the usage of cellular band transistors for 23cm:. Quote from: OwO on September 13, , pm. By using a "single amp" you are not really reducing "complexity". If three Ohm resistors are connected in parallel, and in series with a Ohm resistor, how many resistors do you have?
OP, I assume you know this but I'll say it anyway: one thing to watch for with this approach is that most SDRs have eye-twitchingly bad harmonics and spurs on transmit, so if you're feeding a wideband PA you absolutely need bandpass filtering on the output.
This will also give you some assurance that if the SDR is misconfigured or bugs out it doesn't cause chaos. Bud Super Contributor Posts: Country:. I second the opinion that matching will limit you in simplicity. Over the course of a couple of evenings I modified the output matching to obtain 38 W output for 1W drive at 2. Saturaded power output about 50W.
John's original input matching seems to be spot on, better than 10dB return loss without any trimming. My output matching line is some what longer with less fixed capacitance. At only 2. Returning to the MRF amp it's time to solder a single MRF device back onto the heat spreader after removing the copper ridge between the the original milled cutouts in the heat spreader. Place the unit on the preheated iron and lightly push down on the transistor.
If you have removed all of the original solder then first pre-tin the area the transister will bond to. Using an iron you cannot slide the amplifier of the heat as you can using a ceramic hob but just switch of the iron. The transistor will be hot for longer but this did not seem to be an issue with my amps.
Inital results were very diappointing 1W in, gave 5A current with only 3W output,input return loss only 3db! Adding a 4p7 capacitor to the end of the output matching section increased the power output to 50W and with a few other mods 2. Saturated power output? At this power level you can easily get a nasty RF burn and remember your eyes are even more sensitive to RF damage. I am still experimenting with the amplifier design as I need four units with similar performance.
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