[bars] PSA for FT8/FT4 users - HOLD TX FREQ

Mon May 5 09:06:20 CDT 2025

The quality of your RF output signal has a lot to do with the quality of
the audio signal driving the radio. You can create a poor quality input
signal with too little or too much audio amplitude. Too little can cause a
poor signal-to-noise ratio; too much can put you in a situation where the
signal can become distorted. These problems, if present, will be also be
present in the radio RF output signal.

There is a range of audio levels over which the computer audio system
operates wuth good SNR and low distortion. If you run below or above that
range, your on-the-air signal can be degraded.

The output control in the WSJT app only controls the computer audio level.

So, the point I'm trying to make is that, while you do have some ability to
adjust output power with that audio level, taking the power to extremes
this way may not result in the best signal quality.

The best explanatory example I can suggest is having your radio adjusted
for 100W output, but then reducing the power to 5 watts using the WSJT
audio control. The tiny audio signal from the computer will not be of as
good a quality as a full-range audio output. You would get better RF output
quality if you set the radio RF output to 5W and drive it with a clean
full-range audio output signal from the computer.

Happy digital moding!
--
73 Jim K1IR

On Mon, May 5, 2025, 09:25 Adam Smith via bars <bars at w1hh.org> wrote:

> Chris, All -
>
> One thing that wasn't clear to me as a new FT-mode operator (I'm still not
> a very regular user) was how I should control power output.  There are many
> positions taken / methods used if you search for this online.  Since you're
> basically using USB from the radio's perspective, the actual transmitted
> power is controlled both by the power setting in the radio, and the
> settings in your computer & software which create the audio input.
>
> The advice I've gotten most from operators I trust is - set the radio to
> the maximum intended power level.  E.g. on a desktop rig this could be
> 100%/100W, or say half that if you want to de-rate for digital mode duty
> cycle.  Then use the power output slider at the lower right side of the
> WSJTX interface to control the actual output level.  Make sure that Windows
> (or other OS, but Windows always seems to change things when you're not
> looking) isn't applying some other level control (there are per-interface
> and sometimes per-program settings in the Sound control panel or whatever
> it's called).  Watch the meters on the radio to assess your actual peak
> output and to make sure that ALC is not reaching 100%, which will cause you
> to splatter.
>
> Probably a good idea to start with low power and ramp up after you show
> that you have the audio and control paths working.  You can also check that
> audio is being sent by routing it to the speakers instead of to the radio
> audio interface.
>
> If you come back to the setup after having things disconnected (or after
> Windows has updated), and find that you seem to have no output, check the
> settings on the computer side first.  Especially on Windows I find that
> often the COM port has changed, or gotten disconnected from the digimode
> program, or something ... or the audio/"mixer" settings have changed and
> are sending the output to the wrong place.  Related to that - make sure
> that you're not sending *all* sound from your computer to the rig audio
> interface when it's plugged in - including beeps/alerts, music you're
> playing, etc.
>
> Again, I'm not the most regular FT* user, but you asked for some
> starting-point tips and those are things I've run into while dabbling with
> FT-x, Feldhell, js8call, etc.  Glad to hear from others too.
>
> 73,
> Adam / AA1N
>
> On Sun, May 4, 2025 at 11:14 PM Tim - K1DC via bars <bars at w1hh.org> wrote:
>
>> Congrats, Chris!
>>
>> Please ping me if you have questions.
>>
>> Tim/K1DC
>> On 5/4/2025 16:00, Christopher Lennon wrote:
>>
>> Well thanks for the encouragement all.
>>
>> It turns out that getting receive to work was as simple as connecting all
>> the cables together and turning it on.  Getting it to transmit was another
>> matter.  Hours of YouTube videos later and the settings were right and the
>> G90 quirk that line input gain needs to be maxed out.
>>
>> I didn't call CW, so I didn't show up on the psk reporter, but I
>> completed a QSO with KU4OC.
>>
>> Thanks!
>> Chris
>> W2BPL
>>
>> PS I had hold TXfreq checked!
>>
>> --
>>
>> Courageously sent from a non-Apple device that *includes* a headphone
>> jack.
>> ------------------------------
>> <https://k1dc.com/img/k1dc-qsl-card-front.png> Tim Carter - K1DC
>> +1.978.710.0133 <1.978.710.0133>
>> k1dc.radio at gmail.com
>> https://k1dc.com
>>
>> "Computers are incredibly fast, accurate and stupid; humans are
>> incredibly slow, inaccurate and brilliant; together they are powerful
>> beyond imagination." -- *Albert Einstein*
>>
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>
>
> --
> "Be well, do good work, and keep in touch." -Garrison Keillor
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