To this reply I have attached the images from my NanoVNA, there are two VSWR plots and two smith chart plots.
When using the FT37-43 toroids on the input and output I get about a 1.58 to 1 VSWR at 7.15MHz
When using the BN-73-202 toroids I get 1.093 to 1 VSWR
(When using a full turn on the primary the VSWR is 2.6 to 1 at 7.15MHz and increases rapidly, at 15MHz it is about 6 to 1)
From these two tests I can see the match is much better when using the BN-73-202 toroids and these work well up to 30MHz (VSWR 1.45:1).
Looking at my results so far I can see I get a good match when using 2 x BN-73-202 toroids but the gain out of the NE602 is reduced quite a bit.
