http://www.noding.com/la8ak/c12.htm
Improving SL6440 application
Problem with Plessey SL6440 is low gain, normally -1dB, and gain optimum
is different from noise optimum (NF=10dB), but when operated with some
extra component on 24V this can be improved according to Stein Torp, LA7MI.
A 0.5µV signal produced 10-12dB (S+N)/N with SSB filter in a receiver, so RF
amplifier is still only needed for 28MHz and higher frequencies.