[R-390] Filters

[Bernie Nicholson]

I have converted an I F module to selectable sideband by replacing the 2khz& 4khz filters with assymetrical upper7 lower side band filters that I bought for 50$ for the pair on E place ,Iused a 455.000 crystal out of the 1khz filter to crystal lock the bfo and I put a 6be6 in the bfo and converted to a product det as per HAM RADIO article it works beautifully the audio lines are switched when u turn on the BFO on the front panel and the only conversion is in the I F module ,Of which I have the odd spare ,hope this is of interest , I have three 390A rxs and they perform better on 40 meters among the broadcast stations than my late model 51S1 or my 8054A recievers