[Yaesu] Ft1kMP loss of receive gain

[G3SJJ]

There is a suggestion that my low RF gain could be a fault in the 
roofing filter.

With the IF gain set at 13, I bypassed the filter, ie left it in 
position but put the coax leads back to their original positions. Main S 
meter showed an increase but still not equal to Sub Rx. I though the 
idea was that it showed some gain therefore you back the IF gain off, or 
was that the original Noise Reduction mod?

Could I ask anyone with an MP and roofing filter to do a littler check, 
please.

On any band, find a signal, tap A=B and Dual. What difference do you find?

160m is my best band to try this as I have an s6 power line noise. This 
shows as s6 on the sub Rx but only s1 on the Main Rx, whereas it used to 
be s6.

What should be IF gain be set out without the roofing filter?

Chris G3SJJ