[Yaesu] HF SSB/AM Audio Settings Tx/Rx All Rigs

[WD8ARZ]

Here is a partial review of the various aspects of hf transmitted audio so
as to reduce the confusion between personnal choices vs performance. This
applies to all radios, and not just to FT1000MP. I am also specifically
meaning SSB or AM audio and not FM. I am also ignoring overall power
output, but comparing the same signal under different audio situations.

There are various exceptions to parts of what is discussed here, there
always are. Please keep in mind the over all objective and points being
made, and not getting lost in the exceptions, if, than and buts....thank
you in advance.

How audio "sounds" is greatly affected by what method is being used to
"hear" it. I am ignoring the differences between speakers, headphones,
internal vs external, etc.But those do make a over all big difference,
especially to reduce listening fatique. What I am referring to is weither
your listening to your self through the monitor mode, your asking a local
within a couple of miles of you, a local less than 50 miles, one between
100 and 300 miles, one more than a thousand miles away, and band conditions
at the time of the check. Band conditions are Qrm, Qrn, fading, and weak or
strong signal conditions. Lets not forget that the person receiving your
audio also has adjustments that make a difference, not to mention his/her
own ear performance (did I mention attitude?? hi hi).

It is human nature to want to hear the best possable audio and for it to be
as natural as possable, if the bandwith allows it. However what sounds
"good" and what is intelligible are not the same things. By intelligible I
mean the ability for your spoken words to be understood, "to be heard".
Research has proven over and over again that intelligibility is in the
higher frequency components of speech, and not in the lower. However hifi
sounds is generally supported with the lower frequency range. Thus 100hz
-3800hz audio will sound great and be prefered by most listeners, and
400-2000hz will be judged to narrow. Pushing higher audio frequencies with
out lows will also be chrispy and annoying to some.......but...

Facts are that there is more energy in low frequency components of audio
and your RF output. Thus your RF output will put most of its power into the
low frequencies, And This Part Of Your Signal Will Travel Farther As It Is
Stronger In Watts. So it should be easy to see that tests with locals will
provide high frequency components to your signal that those Further Away
May Not Receive As Well, Or At All. Lost higher frequencies in your audio
means reduced or lost intelligibility. Its a fact that 300/400-19900/2100
range audio is conciderably more intelligible under noisy, long range
communications....even though it receives poor Local reports. Even though
the higher frequency components may be in your signal when they leave your
station along with the lows, the received side is swamped with the lows,
and the highs cant be sorted out very well, especially in noisy conditions.

Bottom line is that there is no ONE way to set your various audio
adjustments to meet all the different Qso circumstances that exist. Thats
why the adjustments are in the radio in the first place, so you can Change
them to suit the situation at hand. For local or strong signal conditions
with out Qrm/Qrn use wide audio range settings, and little to no
compression. For other circumstances start reducing the lows, increasing
the highs, and use some compression. It is not unusual for a far station to
love your audio, and one close in to complain about it.....but the one
complaining can still make out what your saying, Satisfy the local or
strong signal, and sacrifice the further weaker one. A weaker signal can
out perform a stronger one on long haul contacts just due to audio
charicteristics.

Keep in mind that compression will average out audio output for the entire
audio frequency range being used. Thus if your sending lots of lows, lows
will dominate the compression effects. Thats why some start at the mike for
setting the first audio range, then the if filters, and any dsp options.

If you have taylored your audio to fit the long haul hf qso, and used
narrow if filters, and some compression to keep your low audio output leval
up, your transmitting signal will be so much more effective because its
power is being used to transmit Intelligible audio that is needed on the
other end, and not wasted in lows that dont support intelligibility.

It should now be clearer that the settings used in transmitting and
receiving hf signals can have a lot of options. Just because they are not
set for the circumstances being used doesnt make the radio a good one or a
bad one.Good audio starts with your vocal cords, the noise in your room,
the mike, runs through the entire radio to the antenna, hf conditions, the
reciever, speaker and ears on the other end. A problem with any part of
that path can ruin audio. Many older foks or noise damaged ears suffer in
the higher frequencies. It is normal for them to compensate their audio to
make up for what their ears are poor at. So before saying good or bad, why
not instead compare the circumstances and say better than or worse than, or
for this circumstance its............etc, but more importantly, Can The
Words Be Made Out?

I especially like using mode/filter diversity techniques in dual receiver
rigs. Bringing the human brain into play to sort signal information is very
effective in copying signals under various conditions. When the left ear
hears one version, and the right ear a different version, a spatial effect,
almost 3d kicks in that make for very enjoyable listening of what was poor
audio or band conditions. But if the information needed is not in the
signal to begin with, or is not in proportion to the ability to sort it,
even this technique doesnt help. (On a AM shortwave station, put one
receiver on Usb, and the other on Lsb. Use stereo speakers or headphones.
Also try wide filters on one, narrow on the other, Dsp on one, not on the
other, etc etc. Similiar effects for Ssb and terrific affects for Cw)

Distortion is due to wrong impedance mikes, too high gain levals, wrong agc
settings, rfi, alc, phase noise in switching power supplies, incorrect
filter or dsp settings, poor antenna connections or bad coax, phase/fading
bandconditions, signal overload, noise blanker on with strong signals not
far away from the operating frequency, low battery voltage, shielding and
grounding problems, etc etc. Distortion is not what I am trying to discuss
here, just to avoid it.... hi hi Distortion is not the same as frequency
effects.

Sorry, but I can not respond to requests for help with certain makes or
models of gear, or circumstances that you use it under. But it is hoped
that this simplified generic treatment of audio will help you develop a
plan to evaluate the way you configure your radio so you can find what is
best for your gear,  voice/ears, hf conditions, distance, and personal
needs.
 
A great WeekEnd to All !
73 from Bill Stamps - WD8ARZ
E-Mail Reply to:
wd8arz@null.net

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