[Racal] DSP "Smart" Audio Detection-It's about Audio Detection, Stupid - LONG

[2002tii]

[lengthy article snipped, arguing that DSP detection is somehow
intrinsically superior to analog detection with respect to the
intelligibility of hard-to-copy signals]

Intreresting, but contrary to my personal experience.  I have an R-390,
R-390A, SP-600, Drake R8B, JRC NRD-525, JRC NRD-545, Racal RA6790/GM (with
VLF/ELF options), and an HF-2050, all properly aligned and in good repair.
Generally speaking, once a signal is located (easier with some radios than
others), I have found very little difference in copyability that cannot be
easily explained by IF bandwidth and audio EQ (and, in some cases, the
quality of the audio power amplifier).  Here's my diagnosis: the HF-2050
has a seriously non-flat audio response that aids voice intelligibility.
When this response is duplicated (or bettered) with a parametric equalizer,
the other radios exhibit the same (or even better) enhanced
intelligibility, subject to the limits of the available IF bandwidths.

For that last bit of help on really, really difficult signals, I highly
recommend running a radio's line output through a parametric EQ to a decent
preamp/amp and speaker (I use an Ashly Audio parametric EQ myself).

For those unfamiliar, "parametric" equalizers allow one to place boosts
and/or dips in the audio frequency response with three independently
adjustable parameters -- center frequency, Q (how broad or narrow the peak
or valley is), and amount of boost or cut.  They provide an incredibly
powerful way to precisely tailor the frequency response of an audio system,
and can also be used as notch filters if the Q adjustment goes narrow
enough.

Best regards,

Don