[RTTY] RFI Problems

[Patrick Nairne]

Hello
I use a Yaesu FT920 FSK with the Rigmaster Plus interface, and am experiencing a very subborn RFI problem. 
Initially, the problem occurred only on 40M. When the RF power was brought up to anything above about 50W the two tones generated by the FT920 merged into one continuous tone. I then rebuilt the station, putting ferrite rings and rods on every cable. This cured the problem on 40M - but it has moved it to 20M! Advancing the power to anything above 30W or so on 20M results in the loss of the two tones and a long single tone. I only discovered the problem when, wondering why stations were not coming back to me, I monitored my output on another receiver. I am assuming that I do indeed have an RFI problem, and any sugestions would be most welcome. My apologies to anyone who has heard what must sound like a tuning signal in response to their CQ! Oh and thanks for all the contacts in the Volta contest. I managed a few on 20M on 30Watts!
Patrick M0AFZ