Comparison of a FT-847 with cap removal mod on 70 MHz with ref being 50 MHz

By Geoff Pike GI0GDP

This is at 20 W, the result at 70 W is actually good on 70 MHz. It does however suggest self biasing at the higher power level and the bias does need adjusting at lower power levels to avoid spreading.

50 MHz IMD at 20 W.

The 50 MHz result is “valve” like and is very good.

70 MHz IMD at 20 W.

Geoff Pike
GI0GDP