Hi John,
It IS important not to overdrive your audio stage, but that is not the biggest issue.
The problem arises if the audio signals actually transmitted by the computer are
under 1500 Hz...in that case, the audio harmonics can be passed through the filter in
the transmitter and broadcast all across the spectrum.
Before he passed away, W9MDB explained this on his website:
https://www.dropbox.com/scl/fi/avq8nt3higd3evutjssv4/FT8Noise8.pdf?rlkey=xgfxw0bmtdik23h1psu7khz38&e=1&dl=0
GL and VY 73, Lance
On 10/13/2025 18:50:14, John Kludt via wsjt-devel wrote:
Guys,
I thought this all started with an observation that some people hit it way too hard
and generate unwanted harmonics. I have always thought the "cure" for that was to
turn down the audio feed. It is not clear to me how using rig split or Fake It
solves that problem. I always use Fake it - have for literally years. I thought
either method ,Rig Split or Fake It, was about keeping your signal more or less in
the center of the bandpass. I do recall advice somewhere to run higher in the
bandpass rather than lower in the bandpass to move unwanted signals out of the
bandpass - is that why you all are discussing Fake It versus Rig Split? Isn't the
better answer to make sure you have a clean signal and in some cases maybe turn
down the power just a little bit?
Just curious what I am missing.
John K7SYS
On Sun, Oct 12, 2025 at 11:57 PM Reino Talarmo via wsjt-devel
<[email protected]> wrote:
Hi Andy,
Your statement ‘Testing fake-it requires a transmission but rig split does
not.’ without additional information makes no sense to me. Do you mean how
an
operator can see that he is transmitting at correct radio frequency? Most
radios indicate the used VFO frequency, when commanded for transmission. In
the
fake-it operation the RX VFO (A) frequency changes and in the rig the
transmission uses the TX VFO (B). For an indication both require a rig
transmission activation.
If the Tune button is used for the activation, then there is output power in
both cases. If the Test Cat button or the Test PTT button is used, then no
audio will be transmitted, and no RF output will be sent. (If PTT method
VOX is
used, then the Test PTT don’t work and only the Tune button can be used.)
The change of the audio frequency is not presented to the user.
It would be much easier to help in the rig split operation, if at least you
tell us the rig type and how CAT control is arranged.
73, Reino OH3mA
*From:*Andy Durbin via wsjt-devel <[email protected]>
*Sent:* Monday, October 13, 2025 12:24 AM
*To:* WSJT software development <[email protected]>
*Cc:* Andy Durbin <[email protected]>
*Subject:* Re: [wsjt-devel] Enforcing WSJT-X split mode
"I provided a signal report with screen shots to one offending station and
he
improved his signal with audio drive adjustment. He stated he was using rig
split."
Correction - He stated he was using fake-it. Testing fake-it requires a
transmission but rig split does not.
Andy, k3wyc
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