On Wed, 2006-04-05 at 12:36 -0400, Carl Moreschi wrote:
> To get excellent audio, the key is to not overdrive the radio. The ALC
> light should just occasionally blink. I run my EQ settings at the factory
> settings and use a 2400 hertz transmit filter. I really don't think anyone
> should use more than 2400 hertz transmit filter unless the band is very
> uncrowded. The Orion II and Orion version 2 have much hotter audio than
> version 1 and require the mic gain to be set much lower.
>
> Carl Moreschi N4PY
> 121 Little Bell Drive
> Bell Mountain
> Hays, NC 28635
If the mic gain in the radio isn't AT the connector but is after a stage
or two of audio, that first stage can be easily over driven by the
external equalizer leading to distorted audio that radio settings won't
cure.
100 Hz audio will be rejected by my receivers that roll off at about 300
Hz and so is again wasted energy. The original gurus of SSB, Papenfuse,
Bruene, and Shoeneke, said roll 'em off at 300 Hz (partly because the
analog filter slope also is relatively gentle and the added attenuation
of putting the carrier 20 dB down the slope helps need carrier
suppression specs) because you don't need lower frequencies for
communications. Ma Bell did that for long lines as well as for handsets
for most of the last century. And so most receiver designers working
from those tomes and resources roll off below 300 Hz and those
transmitting them are wasting energy. And those with receivers set for
communications bandwidth don't notice the extra basso profundo spectrum.
Yah, I know that spectrum is the basis in trade of the broadcaster, but
ham radio is communications, not broadcasting. AM BC stations run excess
basso profundo voice to compensate for 2" speakers in transistor radios
and AC/DC table radios. When AM receiver audio gets to a good speaker
its boomy, excessively bassy. And still doesn't help understanding.
--
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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