Whilst I had a nice radio in the shack, I looked at the schematics of the FTDX10 and FC 20. Looking at the data cable pin out/in, I noticed that they were the same. I made a control cable of 15Ft as I had placed the FC 20 at the other end of the workshop to where my vertical was fitted outside by the door. Using an 49:1 unun to my end fed aerial.
Setting the FTDX10 to use the EXT Tuner, when I tried to tune up on the band, I could hear the FC 20 trying to match. I found that the radio found it was hard to get the SWR low. (I know the FC 20 was used with my FT847!).
I had to revert to my MFJ-971 Portable Tuner to allow me to use the new radio in the short term on the bands. This had a deep null when tuning and made setting up each band awkward.
I did try to use the FTDX10 internal tuner but again could not get SWR low enough for the EFHW Multi-band Inverted L
More to come……