An available aluminium baking tray, though a bit oversize, came in handy as an enclosure. A piece of aluminium sheet was used to coarsely fabricate a recessed cover.
Calibration was done using a homebrew CW rig and a Weston 1.5A RF Ammeter, after which the variable resistor was replaced by 3 series-wired 10KΩ resistors.
However, the 1:1 transformer could cause the secondary load to be directly reflected as a series load in the feeder. Also, the higher secondary current could result in overheating of the toroid and the 82 Ω resistor.
Hence it was decided to have 20 turns on the secondary side, thereby dropping the load ratio to 400 :1.
The secondary was wound using solid hookup wire and the RF Ammeter rewired.