The housing for the original TUG is a single  piece of aluminum and quite a beast! This should be good for cooling the amplifier. I decided to use the same housing also for the 13cm amplifier and to optimise volume, the two housings were mounted "mirrored" with an aluminum plate in between to guide the cooling air.   The small "legs" were mounted to get some space for directional couplers and power detectors for FWD/REF power measurement.

I used four standard fans to get a good air flow though the fins of the cooler. The air stream is "turned" and returned though the top cooler since I either use the 23 or the 13cm PA.

For 23cm I planned to use four TUG modules. These amplifiers are easy to handle and to modify. For those that come across such amplifiers I can recommend a description on SM0DFP's home page. I followed most of this description except that I replaced the input trimmer by an 1,2pF ATC capacitor. Since I was going to put amplifiers in parallell I wanted to reduce tuning differencies.