The latest version of the LTM's RX/TX card that Dan is finishing up has two RF output power levels: 500 mW and 1W. When he's through testing, I've asked Dan to provide me with the DC power consumption numbers for all the possible modes (TLM only, Transponder Only, TLM + Transponder ----- for High and Low power settings). We know Linear Amplifiers are NOT very power efficient. So I'm expecting this high power mode will require in excess of 3W DC..............we'll see.
As for adding an external amplifier to the 'stack', as JK asked, what is the final RF power level desired? Config-wise one could certainly connect the existing TX coax from the RX/TX card to a stack-mounted amplifier card and control it via QTH/QSH bus signals. But the design requirements would have to be specified and there would be several design challenges and trade-offs. I mentioned DC power consumption for low efficiency linear PAs. Beyond that I would be concerned about RFI effects on other cards in the stack, particularly experiments. Also, heat dissipation is a real challenge were the requirement to be several watts of RF, i.e., thermal issues. Lastly, I'd be concerned re meeting IM levels, i.e., spectral purity requirements from the ITU regulations.
eric