13cm PA for es'hail-2 NB-Transponder

Schematic and Layout

 

Layouts:

alle hier verfügbaren Layout- und Schaltungsdaten dürfen von Funkamateuren zu rein privaten Zwecken benutzt werden, es gilt sinngemäß die GNU-Public License V3. Vor allem: wer diese Daten für eigene Projekte benutzt, muss die resultierenden Dokumente seinerseits wieder kostenlos der Öffentlichkeit zur Verfügung stellen !

Es gibt keinerlei Gewähr für die Korrektheit der Daten. Jeder muss selbst wissen was er tut und die Dateien ggfs. an eigene Anforderungen anpassen.

Auch ist damit zu rechnen, dass ich im Laufe der Zeit immer wieder Änderungen und Verbesserungen an den Platinen vornehmen werde.

all layout and circuit data available here may be used by radio amateurs for purely private purposes, it applies mutatis mutandis, the GNU Public License V3. Above all, whoever uses this data for their own projects, must make the resulting documents available to the public again free of charge! 

There is no guarantee for the correctness of the data. Everyone has to know what they are doing and if necessary adapt the files to their own requirements. 

It is also to be expected that over the course of time I will make changes and improvements to the boards again and again.

 

10W PA, Stage-1 final layout

coming soon ...

 

30W PA, Stage-2 final layout

coming soon ...

 

Prototype Board (functional, but do not use for building new amplifiers)

First prototype, manufacturing data:

Eagle Schematic

Eagle Board

Gerber Data (the gerber file names are compatible with the PCB manufacturer JLCPCB)

assembly plan

 

additional Building Hints:

Mounting the LDMOS transistor:

the MOSFET dissipates the heat through the vias of the PCB to the cooler.

Therefore the bottom of the transistor MUST be soldered to the board. This is not possible with a soldering iron. Instead apply some solder paste to the board (abt. 0.1mm to 0.2mm), place the MOSFET into this paste and then put it into an oven until the solder paste melts. In case of questions about this process watch the Youtube videos about hobby SMD soldering using the kitchen stove, a toaster or other alternatives.

 

Input matching:

the unmodified PCB has a poor input match. According our first measurements two of the spare copper pieces must be connected exactly as shown in this picture:

This matches the input to 50 ohms. 

Many board do NOT require the horizontal connection to the right plane. So its best to make only the vertical connection unless you own an analyser.

 

Power Supply:

the amplifier looks to work with 12 volts. But thats not really true. It generates power at 12v, but it goes into compression very soon. For a good signal a power supply of 24 to 28 volts (1A) is required.

The Freescale reference design uses two separate, symmetrical power feeds to the drain of the Mosfet. It looks to work also with only one feed, but this has to be tested. Currently I mount two +24v wires, one to each connection, both go to the same power supply.