Re: Gain settings with Firmware 1.6.2 #airspyhfplus #bestpractice #firmware

jdow
 

And do remember that if you switch from a signal generator output with signal set at -70 dBm-ish (-90 dBm will also do) to a live antenna with some signals present and the noise increases by more than a little bit (1 or 2 dB) you can insert more attenuation at the receiver's input and not lose any weak signal ability. Obsessing about HF noise figure is one of the silliest obsessions I've seen in innately perverse animate homo sapiens, IPAHS. (Pronounce it.) And, I admit, before I found a good book describing noise figure and atmospheric noise I fell down that rabbit hole of frustration myself.

{o.o}

On 20180313 15:15, Roberto Zinelli wrote:
Giovanni, with 1.6.2 i put  AIRSPY-HF ACG OFF and set attenuator -12 DB,   the overral noise figure for me is better then 1.6.1
On Tue, Mar 13, 2018 at 11:03 PM, Giovanni Carboni <@IZ5PQT <mailto:@IZ5PQT>> wrote:
Here are three spectra around 738 kHz taken with a) FW 1.6.2;  b) FW
1.6.2 plus an external 20 dB attenuator;  c) FW 1.6.1.
As you see in case a) the reception is totally washed out. The only way to
get a reasonable spectrum with 1.6.2 is to turn off the AGC in SDR# and
insert a lot of attenuation.
73 Giovanni

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