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cable wrapped several times around the ferrite to block common mode current from
getting back into the rig. Ten meters seems particularly prone to the problem. Changing
the feedline length has also helped in some cases, but this seems to move the problem
around more than solving it at the root cause. Also, some owners have found that fixing
the grounding of the LPF board by adding solder around the screw holes and in some
cases tightening the screws or adding star washers was sufficient to make their grounding
problems go away.
However, there is a very effective modification that has worked in every case. The mod
involves fixing the grounding in the coax sockets on LPF of the radio and a metal shield
on the Main Unit. A degradation in the LPF grounding can cause the rig to break into
oscillation (even at lower power) causing the HIGH SWR icon to appear intermittently
even with a good antenna match on the higher HF bands. The mod will eliminate this
oscillation and the high SWR reports. Here are a few pictures of the factory installed
mod. The adhesive copper tape has been replaced screws or clamps that are attached to
the casting web. Note that on the upper strap, they have added a screw and the lower strap
was added and soldered to the shield as well as the coax and also screwed to the casting.
Before the factory mod
Summary of Contents for FT-100 Micro Mobile
Page 1: ...Yaesu FT 100 undocumented Compiled by PA3GMP Printed 4 April 2004...
Page 10: ...9 ATAS 100 Disassembly...
Page 11: ...10...
Page 12: ...11...
Page 13: ...12...
Page 20: ...19 After the factory mod...
Page 22: ...21 Prior to modification...
Page 23: ...22 Prior to modification...
Page 24: ...23 After modification...
Page 37: ...36...
Page 46: ...45 FT100 menu settings Entry Set to Description Remarks...
Page 47: ...46 FT100 menu settings Entry Set to Description Remarks...
Page 48: ...47 FT100 menu settings Entry Set to Description Remarks...
Page 49: ...48 FT100 menu settings Entry Set to Description Remarks...
Page 50: ...49 FT100 menu settings Entry Set to Description Remarks...
Page 51: ...50 Frequency list Freq Mode Memory Description...
Page 52: ...51 Frequency list Freq Mode Memory Description...
Page 53: ...52 Frequency list Freq Mode Memory Description...
Page 54: ...53 Frequency list Freq Mode Memory Description...
Page 55: ...54 Frequency list Freq Mode Memory Description...