[TenTec] intermod on Jupiter when decreased RF Gain?

[Ken N9VV]

Dear Jupiter owners,
did anyone ever notice intermod when they lower the RF Gain? I 
have been tuning around on 80M tonight with the RF Gain set to 
only about 25% because of QRN crashes. I hear a lot of SSB, AM and 
what I would call birdies - until I crank up the RF Gain to more 
than 75% where everything is normal (but very noisy).
your thoughts?
BK de ken n9vv