locked Re: VFO B Shifts From 7074 to 7073 On Transmit When Using Split On Yaesu FT-991A? #Cat_RigControl

Michael Black

To be a little more descriptive....

In order to avoid harmonics and bandwidth limitations Rig Split and Fake It both adjust the transmit frequency so that your audio is maintained in the 1500-2000Hz range in 500Hz segments.
One major advantage is when you see somebody calling above 2500 offset you can go up there with them even if your transmit bandwidth is less than 2500Hz as your audio will still be 1500-2000Hz -- well within your bandpass.

So as you go below 1500 offset your transmit frequency will go down 500Hz so that your audio is still 1500Hz above the suppressed carrier frequency.  Above 1999 frequency will go up.

14074000 with offset of 1500
14073500 with offset of 1000
14073000 with offset of 500
14072500 with offset < 500
14074500 with offset of 2000
14075000 with offset of 2500

Mike W9MDB

On Tuesday, October 5, 2021, 06:37:19 PM CDT, Sam Birnbaum via groups.io <w2jdb@...> wrote:

Hi  Cliff,

That is normal operation when using split = rig. It is shifting the frequency so 
that your TX audio is in the middle of the band pass.  

FYI, you do not have to press the "VFOA=VFOB" The program will do that for you.



-----Original Message-----
From: Cliff Fox (KU4GW) <cliffku4gw@...>
To: main@WSJTX.groups.io
Sent: Tue, Oct 5, 2021 6:26 pm
Subject: [WSJTX] VFO B Shifts From 7074 to 7073 On Transmit When Using Split On Yaesu FT-991A? #Cat_RigControl

I'm having an issue and I don't know why it's happening when operating on FT8 when I use the Split setting under the Settings, Radio tab. I was operating on 40 meters and set VFO A to 7074 kHz in DATA-U mode with AGC off and then pressed VFO A=VFO B  to copy the same settings to VFO B and if I'm transmitting as low as 400-800 Hz audio frequency when the FT-991A transmits it's shifting VFO B to 7073 for some reason. If I were transmitting at 1000 or above I would expect a shift up. I turned split off and chose "Fake It" in the WSJT-X settings because of it doing this. It had not been doing this until this past week it started happening, I'm thinking possibly due to operator error. Can anyone tell me what could be causing the shift on VFO B from 7074 to 7073 when I transmit and what would keep it from doing that when using the split VFO setting? Thanks in advance from a real greenhorn on a new to me mode.

Very 73 de 
Cliff, KU4GW

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