Build a Ldmos 70cm power amp capable of 1kw on 70cm.

I contacted another ham who had in the UK a W6PQL amp kit that he did not build , so i saved quite a bit getting this and the shipping as the kit came from the USA originally.

Never built one of these before , but i can build most things .

here is the amp during construction.

the dual LDMOS flow solderd to the copper pallet , we had an RF arc during testing ,

the white coax got to hot and desoldered itself producing a powerfull RF arc, extra cooling overt the top of the amp and tuning the amp propery cured the problem.

measuring the matching on hte feed to the amp

Low pass filters, i decided to add anothe band to the amp as there was prenty of room in the case and a large heatsink.

the sequencer

showing the mast head unit with the relays and LNA

front panel

the main 70cm pallet before fitting in the case.

some flash overs on the LPF filters on the 2 meter band , had to move the board top side and give cooling .

you can see the black area where the capacitor let go 

some other issue with the PSU , it trips on times with te RED led coming on the 50v then shuts down , this is a puzzle as it does it even if i remove the PSU from the case and power it stand alone !.

 

normal green

error tripped.