Hi Artur
do you have good results with this PA? can we have the PCB? or the corresponding file
73 f4fdw Laurent
Hi Artur,
I have build your PA with your PCB, but I run into some problems. The provided output match has a maximum at 2.1GHz and falls down -13 dB to 2.4GHz. The design looks like the test circuit for 2.1Ghz from the datasheet. I was able to get a much better match for 2.4GHz by changing the existing ATC caps.
Your PTT need DC from the input. I have changed it to external.
You have covered the backside of the board with solder mask. It has has a thick one. I have scratched off most of the solder mask to get a better thermal contact to the heat sink.
With this modification i get nice 16W at 2.4 GHz.
73, Peter DC2PD
Display MoreHi Artur,
I have build your PA with your PCB, but I run into some problems. The provided output match has a maximum at 2.1GHz and falls down -13 dB to 2.4GHz. The design looks like the test circuit for 2.1Ghz from the datasheet. I was able to get a much better match for 2.4GHz by changing the existing ATC caps.
Your PTT need DC from the input. I have changed it to external.
You have covered the backside of the board with solder mask. It has has a thick one. I have scratched off most of the solder mask to get a better thermal contact to the heat sink.
With this modification i get nice 16W at 2.4 GHz.
73, Peter DC2PD
I have changed BIAS resistor to 27r and replaced divider to ground (ex 110r*) with a 100r preset. The highest I am getting the BIAS to go is around 360mA. With about 700mW I seem to hit saturation and I am getting around 16W in CW mode. HP meter cannot read PEP. Do you think I should stop here and not push my luck ?
update...changed 100r preset to 1k preset to get more range...i can set bias now to 450ma or more but i stop at 450ma....can hit 20w avg fm in ssb mode "whistle" i see 22w peaks...max current is 1.6a at 28v...freq 2320mhz at 2400mhz there is about 1.5db lower. I can say this is working great now but the fan running on heatsink makes a BIG difference and keeps bias stable. these readings are after abusing 5mins key down in FM..i risked it as i have 10pcs spare ldmos on order from digikey i only managed to kill 1 so far after i slipped the meter probe on bias track and hit drain track they are so close...the magic smoke was very quick to release and burn €20 device 
but good experience for when using €200 device ! SP3OSJ FB thanks for PCB although you have made it to fit in a specific case I would personally have made a generic PCB with more spacing and easier to fit M3 screws with more spacing but you had to adapt to the wifi case you had so understandable
Hi
Thank you for a good review. I bought BLP9G0722-20G in China at $ 9/piece. They will sell me the original transistors:
https://de.aliexpress.com/item/4001241935303.html
I now change the design and put in a new housing like my TRV. Now you can make 12V power supply because there is a step up converter with potentiometer regulating from 12V to 30V.
73
Artur
FB Artur ! I suggest to put a directional coupler in the new extra space by the output trace !
Display MoreHi
Thank you for a good review. I bought BLP9G0722-20G in China at $ 9/piece. They will sell me the original transistors:
https://de.aliexpress.com/item/4001241935303.html
I now change the design and put in a new housing like my TRV. Now you can make 12V power supply because there is a step up converter with potentiometer regulating from 12V to 30V.
73
Artur
Good morning,
my power amplifier runs well with 43dBm without a cover. As soon as I put the cover of the housing on, only 41dBm come out. Does anyone have a good idea?
73 Ulrich
Any mechanical problem ?
Moin,
was soll an der Mechanik daran sein. Wie gesagt wenn da ein Deckel drauf kommt.
73 Ulrich
Hallo Ulrich,
was macht die Stromaufnahme? Geht die auch entsprechend zurück wenn der Deckel drauf kommt?
Robert
Hallo Robert,
der Strom bleibt konstant.
Ich werde mal zwischen Ein.- und Ausgang eine Abschirmwand machen. Vielleicht koppelt es, durch die Reflektion im Gehäuse die HF.
Ulrich
Hallo DL3ED,
vielleicht hilft es, unter die beiden Schrauben bei den Massefahnen des Endstufentransistors dünne Kupferfolie zu legen und mit den Massefahnen und den Massepunkten zu verlöten.
73, Martin
Hallo Ulrich,
wenn der Strom konstant bleibt bedeutet dies, dass der Transistor ja weiterhin die volle Leistung produziert, er es aufgrund einer Fehlanpassung nicht mehr schafft die Leistung an die Ausgangsbuchse zu liefern.
An eine Kopplung zwischen Ein- und Ausgang glaube ich nicht.
Ich denke eher, dass, wie Martin schon schreibt, die Masseverbindungen der Leiterplattenunterseite nicht ausreichend sind und bei aufgesetztem Gehäusedeckel dadurch die HF andere Wege nimmt. In jedem Fall muss die Masseseite der Leiterplatte rund um den Transistor und dein Ein- und Auskopelinduktivitäten gut mit der Masse des Kühlkörpers/Massefläche verbunden bzw. verschraubt sein.
73 de Robert
Hallo Robert u. Martin,
das kann sein, denn das Gehäuse ist eloxiert. Das vielleicht dadurch kein Sauberer Konrakt da ist. Werde ich testen. Danke.
73 Ulrich
Gutn Morgen Artur,
werde ich machen, danke.
73 Ulrich
