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Rev 1.01 

3

 

The easiest place to take RF from the Ultimate3S is at the Q2 or Q3 transistors. The best way to cut 
the RF circuit between the original Ultimate3S PA and the Low Pass Filter on the U3S PCB, is to 
remove capacitor C5. If you don’t mind a little aggression you can even just cut it out with wire 
cutters. For routing the RF output of the 5W HF PA kit back to the U3S, it is easiest to connect a wire 
to the “RFI” (RF in) pad.  

 

Single-band Ultimate3S with 5W HF PA kit 

Содержание HF PA kit Series

Страница 1: ...w to interface the PA kit to the QRP Labs Ultimate3S transmitter kit The assembly document for the PA kit is ESSENTIAL reading prior to this application note 2 Block Diagram The basic Ultimate3S trans...

Страница 2: ...timate3S stack then you will need to put the 5W HF PA kit at the BACK of the stack due to the 65mm tall heatsink You will also need to purchase a set of four 25mm nylon spacers from the QRP Labs shop...

Страница 3: ...the original Ultimate3S PA and the Low Pass Filter on the U3S PCB is to remove capacitor C5 If you don t mind a little aggression you can even just cut it out with wire cutters For routing the RF out...

Страница 4: ...Rev 1 01 4 Multi band Ultimate3S with 5W HF PA kit and relay switched LPF kit...

Страница 5: ...g rather than a plug socket solution The RF connections between boards can be thin coax but don t worry if none is available and you just need to use a piece of hook up wire The envelope control signa...

Страница 6: ...e DAC A safe value would be 115 for a 12V supply or 140 for a 13 8V supply Please refer to the PA Assembly instructions section 5 3 for an explanation of this value and for values that suit other PA s...

Страница 7: ...the PA Assembly instructions download at the PA Kit page http qrp labs com pa For any questions regarding the assembly and operation of this kit please join the QRP Labs group see http qrp labs com g...

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