[Elecraft] K3 - FT8 - low power issues when TX audio below 900hz

[Keith Onishi]

If your WSJT-X is enabled to CAT control your K3, WSJT-X change VFO frequency on transmit so that FT8 AF frequency into K3 is center of TX filter.

However, before WSJT-X has this feature, I did not have any issue on transmitting < 900Hz AF.
Are you using DATA-A mode on K3 for digi-mode? If you use SSB mode on K3 for digi-mode and TX EQ has been set to reduce <900Hz audio level, this could be the cause.

73 de JH3SIF, Keith

> 2018/07/19 4:11、LA8AW <oddyen at gmail.com>のメール:
> 
> Hi,
> 
> On all HF bands I have very low power output when I TX with a audio
> frequency below  900hz. Between 900 - 2300hz all is normal.  On 50Mhz,
> power the output start dropping when I come below 500Hz. (FL1 2.7 selected
> on all bands)
> 
> Using Microham MicroKeyer II; Audio switching is set to Digital settings,
> using line in (rear). Tested with 2 different MicroKeyer II same result.
> 
> FT8 is soundcard configured Input: Line (microham CODEC), Output: Headset
> Earphone (microHAM CODEC).
> 
> This was causing problems for me when I tried to work stations running DX
> Mode (KH1).
> 
> K3 with the "new" synth card, all mods done.
> Filters installed: 2.7, 1.8, 1.0, 0.4, 0.25
> DATA enabled for all filters
> 
> Any hints on where to look next?
> 
> 
> 73 de LA8AW - Odd-Egil
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