Dummy Load
This dummy load was constructed using a Aluminium processor heat sink and one of these (picture to right) thick film 50 ohm resistors from the internet (ebay). They are rated at 40 watts CW and much more for short durations(Peak Power: 400 Watts (based on 10us pulse width and 1% duty cycle). On a large heat sink they are supposedly able to handle 100 watts SSB for a few minutes.
First I drilled a hole right through the heatsink to take the inner coax conductor and PTFE insulator. Then using a taper drill, made clearance for the UHF socket pin and insulation.
This allowing the socket to fit nice and flat on the heat sink ready for the fixing holes to be marked and drilled as can bee seen in the picture bellow.
Fixing holes drilled out
Heat sink drilled and ready to take socket and coax feeder
Thick film resistor in position ready for marking out and drilling
Resistor fixed in position with good quality thermal past and feeder soldered to flange. This connection is very delicate so great care when soldering should be taken.
Some copper plate has been shaped to protect the resister and also help to transfer heat away form resister.
