[CQ-Contest] Re: SSB tuning & RADIO IMPROVEMENTS

Bob Perring perring at texas.net
Mon Feb 16 09:45:53 EST 1998

At 09:40 2/16/98 -0500, Richard Gelber wrote:
>I would suggest that part of the problem may relate to unfamiliar

This comment/analysis was in response to KG5U remarking about having to
re-tune his radio quite often in order to properly receive the
transmitted SSB audio of many stations that he recently worked on the
20 meter band (SSB).

I believe that Richard has stumbled on to a little known secret that
has not been spread around very much for everyone's benefit.

On most Japanese radios, there can be realized about .5dB gain in talk
power by making modification to the R-C time constant components in
both the receive and transmit audio circuitry.

When these radios are built, they are tested at the factory by a male
Japanese voice, but, as you might imagine, this does not suit every
consumer. There are youth voices to be considered and the are YL/XYL
voices to be considered.

Additionally, the audio circuits are designed around the time constants
for the Japanese syllabic consonant and vowel enunciations. These
Japanese syllabic time constants do not necessarily correlate
accurately with the American time syllabic articulation parameters.

There are a few situations where the values are similar, such as when
operating on 75 meter SSB and uttering stupid curse words in an excited
manner to contesters, but this is one of the very few cases where
American speech syllabic values and the values of the Japanese tester
might seem to be somewhat equal. 

This "equal condition" seems to be more a function of the factory
tester being on a time clock, and speaking his words more slowly on
Monday mornings and Friday afternoons, bringing the test values down to
a slower American rate; closely to East Coast Jersey talk, but not
quite down to a Texas drawl rate.

As for deciding the proper value of components to install in your radio
so as to realize the "talk power" gain for your particular style of
speaking, the manufacturer of the radio should not be contacted
concerning these modification component values. 

The manufacturer's local country distributor should be communicated
with, instead. Obviously the values change from country to country, and
region to region.

In the case of my old FT-101 (EE, and another E), extensive capacitor
changes were mandated in order to more closely tune the transmitted
audio of the radio to my then youthful 23 year old voice. 

If I were to still have that radio in my possession, it might very well
be necessary to again change those capacitors, as they have matured
with time, as has my voice.
It should also be noted, as an interesting side aspect to this circuit
maturation design analysis, that the original radio design parameter
maker (tester) has, most likely retired, and is now living on a pension.

I suggest that these audio component value modifications should be
performed only by a trained technician.

So, you are now thinking about your code speed, vs. the optimum
operating code speed around which the radio was designed for at the
factory, I would suppose, heh ?..........

Well, proper rise and fall values for CW are another matter. Most
Japanese rigs seem to do quite well at the slower code speeds of First
Class Operators (FOC), but at the higher code articulations of the
Chicken Fat operators (CFO)  there has often been required extensive
modifications. This is not true on older American radios and the
current line of Ten Tecs.


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