locked Re: Audio Frequency choice. #QSO_practices


Bill Somerville
 

On 24/09/2021 23:12, mbigos@sonic.net wrote:
Hi -

I have been using FT8 for 4 months on 40 & 20 meters and notice that signals bunch between 1 kHz and 2 to 2.5 kHz. Can someone explain to me (or point me at some good write-ups) as to why this happens? Is there some magic going on that I am missing, or is it just herd instinct? I generally try to use 800-950 Hz, and get reasonable results with a QRP rig and compromise antenna. Thanks in advance, 73.

Marty
KN6OKN
Hi Marty,

one reason may be that users who do not have CAT control of their rigs are following our advice to use Tx audio offsets above 1500 Hz. This ensures that any unwanted audio harmonics are greatly attenuated by the rig's Tx IF filter. Of course they can elect to tune their VFO dial down 1 or 1.5 kHz if they wish to get to those lower frequencies.

73
Bill
G4WJS.

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