Reacting to the story “High-Definition Expanded Radio” on RW Online (see below), Derek Kumar of Digital Radio Express writes in reply:
Shame on Radio World. You’ve just helped Hal Walker fool a new generation of readers with the dubious VMSK technology. First off, this so-called system isn’t even an FM SCA — it’s more of an IBOC/IBAC thing. Did you even bother to look at their own Web site www.vmsk.org/FMSCA.pdf? The spectrum clearly shows the VMSK signal on only one side of the standard FM modulated carrier. This is physically impossible with a true FM SCA system. Moreover, VMSK is a delusion. It was debunked years ago by Phil Karn of Qualcomm, among others. Must-reading includes http://people.qualcomm.com/karn/papers/vmsk/
VMSK puts virtually all of the energy in the carrier so that the data-bearing signal is “in the grass.” Of course, it is useless at this level. Unfortunately, along the way, small investors have lost a lot of money through the various shell companies involved (Pegasus Data Systems, AlphaCom) and now this.
You have done a disservice to your readers, many of whom do not have the technical acumen to determine what is a perpetual motion machine and what is not. That’s not their fault — broadcasting is more about content than technology — but it is even more reason for technical editors to do proper due diligence before giving such claims front-page attention.
Derek Kumar
Digital Radio Express, Inc.
Milpitas, Calif.
