Wednesday, April 24, 2019
Some Further Thoughts regarding Stereo CW
It has been quite some time since I originally shared my discovery of Stereo Cw.
([CLICK HERE] to read the original article.
You don't need a dual-watch or dual-receive radio to transform your stereo headphones into an incredible operating experience. With Stereo Cw you DO need to be ready for signals to be shifting around "inside your head" as you tune THROUGH a signal or use the R-I-T control to "position" the signal "in your head"; or, if you prefer, "between your ears".
Properly centered, tuning the R-I-T +/- 150 cycles can "position" a signal in the upper-left of my hearing or the upper-right. With the R-I-T = 0, the signal "appears" to be "in front" of me. At first
this takes some getting used to; then, later, you wonder how you ever ran a radio contest without it.
that circuit by way of two outboard filters properly offset from each other. For my portable setup at W7AYT's QTH I use a pair of Autek QF-1A audio filters; one for each ear.
To enhance my operations from Alameda, I recently implemented a filter combination; an Autek
QF-1A for the left ear and an MFJ-751 for the right side. Separate splitter cables separate the
input audio towards each outboard unit and recombine it back into a stereo cable plugged into
a wireless headset transmitter.
An additional advantage to using Autek QF-1A (or MFJ-752) outboard filters comes from the auxiliary notch filter those units have; the MFJ-751 possesses no such additional filter. This secondary [notch] filter can notch-reduce a signal in the passband for that ear. Use of these external filters takes the concept of an APF (Audio Peak Filter) circuit to the next level.
noise and QRM.
Combining analog and digital technologies allows co-leveraging BOTH methods to alleviate
a single/combined source of QRM & QRN. Realize that every attempt at filtering audio may itself introduce its own "artifact" (QRM). For example, "pushing" the QF-1A filter to its limit may introduce "ringing", requiring that the filter intensity be "backed off" a little.
With external audio filters adjusted similar to the above-mentioned setup, running pileups becomes considerably more DO-able; different signals with different offsets are experienced either in the left-side, right-side or "middle" of the listener's "Experience".
Stereo CW is an incredible augmentation to radiosport signal copying. While it does nothing to boost the transmitted signal, it makes once-difficult copy copyable. Regardless the quality of the transmitted signal, if "I can't hear 'em, I can't work 'em".
What about You? What do YOU do to make signals more readable?