RF Gain 6400

DonE

I have attached two screen shots . As you can see I

-8 gain.PNG

+ 32 gain.PNG

must run quite a bit of gain to hear stations . I had a problem last year with receiver going to sleep and sent it back to Flex twice . I don't remember needing to run this amount of rf gain prior to that trip. They replaced B-0097 DE AD9467 ADC board on one trip and B-0093 DELPH on second trip. Is it normal to run that amount of RF Gain?

Stan VA7NF

Your two attachments show correct operation on the two RF gain examples; primary focus is on the front end analog to digital conversion.

Your band is very quiet on 20M and only 1 station is visible above (-104dbm) the threshold (-111dbm).

The second example has added 40dbm of gain moving the threshold down to approximately -150dbm, with the panadapter showing a background noise of around -142dbm. If you want to hear all the noise then an antenna gain of around +24 would be suitable. Also observed is the signal shown on the first example is still there AND still the exact same strength (-104dbm) with just the visible threshold lowered exposing the other signals.

Flex staff have discussed the available dynamic range of the A2D converter and recommend, in environments with very high power stations, to keep the RF gain down. Your environment is very quiet so, to see and hear all the noise, you need some front end RF gain.

As you raise the gain you expose more signals until reaching around +24dbm gain, where any more gain only reduces your available dynamic range with no benefits. So use +24dbm gain to hear everything, especially noise, or +16 to hear the stations with no/greatly reduced background noise (comfortable listening).