Pipeline Profile: Richard (Dick) Shimp

Broadband Background: In 1969, Shimp joined Warren L. Braun Consulting Engineers, from which ComSonics eventually evolved. He has been an SCTE Senior Member since 1979 and is a member of the Loyal Order of the 704. What can you tell us about the origin of commercial leakage detection? Throughout the 1970s, several events stimulated interest in cable TV system signal leakage: the introduction of 47 CFR §76, Subpart K in 1972 and a subsequently reported incidence of interference to aircraft navigation audio from a cable plant. While the Subpart K release defined legislative leakage limits, the interference issue spawned the Advisory Committee on Cable Signal Leakage at the hands of the FCC and FAA and dealt with practical application. Meanwhile, however, a ComSonics’ client became plagued by a closely related problem that prompted the creation of a super sensitive detector device. The issue was radial sheath cracks beneath the coaxial cable jacket at badly formed expansion loop bends; the device was branded Sniffer. In late 1974, we (ComSonics) introduced the prototype predecessor to the Sniffer system. The prototype operated at 217.2500 MHz, pushing it to unused spectrum at the upper end of the amplifier passband. Testing we conducted in the suffering cable plant validated the concept, but identified the need for an accessory to zero-in on the actual break location and the need for an unmistakable tone on the leakage test signal source. By 1976, the new Sniffer Leakage Detector and accompanying Sniffer Signal Source made their production début. How did you play a role in the development of this technology? I developed the original Sniffer System initially to satisfy the fractured sheath under jacket issue. I gathered mountains of measurement data from simulated plant constructed outside our Virginia facility and from passive hardware emission measurements made from highly sophisticated metal trash-can test fixtures. I hosted representatives from the FCC at our facility several times during the Advisory Committee investigations and served on the Advisory Committee. Very quickly after introduction, the Sniffer System became the standard of the time, and we finally gave up trying to protect the registered Sniffer mark. The industry insisted on calling all leakage products Sniffer, regardless of vendor. How is the industry doing on plant integrity and leakage? From what seems an eternity ago when CLI became an industry buzzword, the focus centered on controlling cable signal leakage to a level providing a low probability of interference to airborne navigation and communication channels. Even with the challenge from the FCC in the 1972 Rules, the importance was interpreted differently across the MSOs, resulting in a sluggish start. With enough FCC pressure, particularly through fine levying, folks began to take notice. And as the practice proliferated, operators surprisingly discovered that paying attention to signal leakage yielded heretofore-unrealized rewards: reduced trouble calls. Nothing impacts contemporary shielding integrity concentration more heavily than ingress. This, of course, results from the need to quiet the return path spectrum. The industry is at the threshold of DOCSIS 3.0 implementation. Even though the wider required bandwidth needn’t be contiguous, it nonetheless must exist with adequate headroom. Clearly, there is a physical limitation to the degree digital signaling errors can be corrected. The only remaining solution appears to be controlling the reasons errors occur and the most efficient way still monitors leakage. One day digital cable signaling will proliferate, likely even eliminating simulcast. For a number of reasons, a digital multiplex signal makes a terrible target for signal leakage monitoring. Yet, future services demand ingress susceptibility no less than the best existing today. We’d best all burn some brain cells arriving at a usable solution. I believe the industry is doing a bang-up leakage maintenance job that puts us, today, much ahead of where we were in the beginning; can we do better? Is the knowledge base among technicians rising or falling? Our technical community transformed this industry from not-so-simple coaxial broadcast of 12 or less analog TV channels to delivering a combination of 50 or more analog TV channels, two and maybe more times that number of digital TV channels, CD quality audio, high-speed data and telephony over a combination of fiber and coaxial cables. How is it possible for the knowledge base to remain static? Roughly categorized, the industry supports four technician classifications: headend, field supervisor, service and installer positions. These are the folks charged with keeping photons and electrons zinging back and forth, hopefully within the plant. From supervisor to installer, everyone’s task has taken on a new character. And so has the instrumentation issued. Those of us around for more than a few years readily remember the meager test equipment beginnings and how, over time, instrumentation evolved to that available today. The headend crew cannot function simply with a signal level meter. But neither can the field supervisor or the service tech or the installer. But no matter the instrument’s sophistication, there is no substitution for a knowledgeable technician. Enter SCTE’s comprehensive certification program. Do technicians need more tools? I think introducing more tools probably points the wrong direction. A better approach would supply each technician with the correct tool to most effectively complete her/his task. Do you have an opinion on whether they need laptops? I don’t think this is a practical solution for our industry. Limited in scope to only that needed, instrumentation can be made more cost effective and yet functionally more powerful to the technical community with far less unneeded stuff and more needed stuff than normally populates a laptop. A good example of a common needed stuff feature could be creating a workforce management standard. Unfortunately, some administrative pain might be encountered in the process of marrying back office and maintenance data silos. Paperwork solutions likely have been put into place as needed to support subscriber services evolution, and renovation may be challenging. However, it seems advantageous for technicians at all levels to have immediate access to a common database of pertinent plant and subscriber information during installation and/or a trouble call.