By Mark Frink
FOH Magazine, January 2012
Kaltman Creations has been selling German handheld RF (and EMC) spectrum analyzers from Aaronia for several years now, as well a previous version of Invisible Waves, a Windows-based RF spectrum scanner. The new version, Invisibles Waves X is again comprised of hardware and Windows-based software components, but now the software’s user interface has been improved to provide a better RF command center.
First is the hardware, which comes in a 16 x 10 x 4 inch clamshell plastic case with a handle, which I’ve since replaced with a larger Pelican case that also holds a Netbook PC and a directional paddle antenna, neither of which is included.
The main hardware is the scanner itself — a 6 x 3.5 x 1.25 inch aluminum case. It has a power switch and blue LED on one end, and connections for a 4-foot USB cable, a 0.8A 12V DC power supply and a ¼-36 SMA (SubMiniature version A) co-axial screw-on antenna connection, like those found on PCI wireless cards and on high-end WiFi routers. The required accessories — USB cable, power supply and whip antenna — are supplied.
Also supplied is a second WiFi antenna if purchasing the IWxAV version instead of the IWxLIVE, which doubles its range from a ceiling of 1.8 GHz up to 3.5 GHz, allowing measurement of 2.4 GHz WiFi spectrum, of great interest for newer WiFi wireless and the many other technologies of interest in that spectrum. The IWxAV version costs an additional $300, but it’s well worth it considering that WiFi (or BlueTooth) isn’t going away any time soon, with more AV appliances using it every day.
An option I didn’t elect is the IWxBATT 2.0A-h lithium polymer battery pack, conveniently packaged in a similar 6 x 3.5-inch chassis and rated for 4 to 5 hours of use, longer than most laptops will last. The battery is indispensable for those who must make measurements in the middle of a field (or stadium), or as soon as they roll out of a bus bunk, and it also serves as a UPS while making measurements.
The scanner itself is an OEM version of WiNRADiO’s third-generation WR-G305e software defined scanner. The Melbourne, Australia-based company has been around since the 1990s, and I own one of their older scanners, a WR-1550e. What Kaltman Creations has done is focus the abilities of WiNRADiO’s scanner by programming a custom front end to make it a better tool for wireless technicians.
IWx ships with a flash drive holding installation software. Minimum computer requirements are a Windows XP, Vista or Windows 7 computer, with a 2.0 GHz CPU and 2 GB of memory. I do most computer work on a Mac, but with the low cost of PCs these days, a dedicated laptop to bundle with Invisible Waves isn’t that expensive. I bought a 1.66 MHz, 1GB HP Mini 210 Netbook on eBay for $200 and loaded it with XP, and IWx ran just fine. Initially I used it with a second VGA LCD screen, but the Mini’s 1366 x 768 resolution 10-inch display proved ample, given its flexibility.
The software is more of an RF “command center” than a straight analyzer. Its various windows can be resized or moved around the screen, and smaller windows can either float on the screen, “dock” alongside the other windows or be closed and then reopened from the icons on the tool bar above when needed. The flexibility of this scheme is powerful. As users become more familiar with the software, they find themselves using some screens less and focusing on the Master Status Display.
Upon starting the software, there are three main display windows: the Spectral Trace View, which analyzes RF strength across the defined spectrum; the Master Status Display; and the HeatMap, which is similar to Smaart’s Spectrograph, showing hotter regions of RF spectrum as brighter colors. While HeatMap is intuitive, it’s one of the first windows to close and make more room for others.
The Master Status Display window holds individual sub-panels that the user sets up for each wireless system. Each panel has a name, an assigned frequency and one of six background colors (Green, Blue, Light Blue, Magenta, Gray and Light Gray). Every wireless system’s signal strength can be seen at once in this Master Status Display, continuously showing signal strength on a 100-segment red-yellow-green horizontal bar graph.
The white frame around each sub-panel can turn yellow and then flash red when its bar graph falls into those regions. Additional alarms are logged for both low-level systems and new Unidentified Frequency Objects (UFOs). A data recorder can save IWx parameters to be viewed at a later time to study intermittent interference.
I feel about Invisible Waves X the same way I felt about the Smaart Live when it came out. IWx’s improved user interface, combined with today’s increasingly challenging RF environments, moves the application from interesting to indispensable.
Custom Profiles allows users to store all of IWx’s settings for later recall. Master Status Display Panels can be saved into “presets” with the “Save Master Status,” powerful for daily users, whether local vendors or touring technicians.
I’ve been using IWx for over a month for several shows, for both in-ear monitors, wireless mics and combinations. It’s a great comfort for RF technicians as well as their clients, whether they’re other sound engineers, artists, presenters or lay people, as it takes the mystery out wireless operation by simply being able to see what’s out there.
Wireless frequencies are often chosen either randomly, by “scanning” a receiver for open frequencies or employing blind faith in recommendations of zip code driven on-line resources. IWx allows users to verify their current environment and then continue to monitor it in real time during a production.
Ultimately, there are two or three types of IWx users: One is touring productions with a fixed inventory, moving from one RF environment to the next. Next are regional vendors in a constant RF environment, employing various combinations of inventory from day to day. Third are in-venue users with constant location and inventory, but where introduction of visiting RF equipment imposes a higher requirement for frequency coordination.
After using IWx for a while, the typical ragged 6MHz-wide mesa-plateau shape of DTV broadcasts becomes familiar. These are the local UHF fence posts that wireless technicians must navigate around. For the touring RF tech, wireless inventory remains the same, and the DTV broadcast fence posts change each day, from one city to the next. IWx’s Master Status Display panels built around a tour’s wireless inventory can be saved for the next city, needing only to move frequencies that conflict with each new city’s set of DTV transmissions.
Another way of using the Master Status Display is to set sub-panels for each DTV broadcast using the center frequency of the 6 MHz-wide broadcast and a 6 MHz bandwidth. Users can color-code the sub-panels, and I used green for IEMs, blue for wireless mics, light blue for the lead vocal its spare and magenta for backline wireless, leaving gray for the DTV broadcasts. In this way, the signal strengths of all the frequencies of interest can be visually scanned like the meter bridge on a console.
For local vendors, their city’s DTV broadcast fence posts remain the same and so can be saved from one project to the next, while new frequencies are chosen for each production’s inventory, opposite of the touring RF tech. House engineers who work at a single venue have it easier, as both RF environment and inventory stay constant, other than supplemental wireless for bigger shows or wireless brought in by visiting artists.
Whichever category you’re in, Kaltman Creations’ Invisible Waves X system helps RF techs manage wireless mics and IEMs better and more efficiently. The touring engineer can quickly verify constraints of the day’s new RF environment, the local vendor can chose frequencies without guesswork, and in-house techs can easily trouble-shoot new situations.
Several features are worth mentioning. UFO Alert™ (Unidentified Frequency Objects) warns when a new RF signal appears above a defined threshold (like a support act turning on wireless). RF Level Alert™ warns when any RF signals on the Master Status Display’s sub-panels fall below a threshold (such as talent turning off their transmitter or leaving the venue). Click to Listen™ allows RF techs to actually hear a transmission where IWx’s cursor is located (providing confidence monitoring for hearing assist systems or just identifying rogue transmissions). Finally, IWx’s RF Coordinator™ identifies usable open spectrum to aid in choosing frequencies.
The system has a couple of shortcomings. While its RF Coordinator can choose open spectrum, it can’t coordinate sets of wireless in RF groups to avoid inter-modulation (IM). Using manufacturers’ pre-coordinated frequency groups is still the best insurance, or, for more complicated wireless projects, multi-channel frequency coordination software, like Professional Wireless Systems’ (PWS) Intermodulation Analysis Software (IAS).
That said, IWx is powerful, even when there are no rogue transmissions, simply because its constant visual aid helps RF techs do a better job of employing best practices by continuously displaying the RF environment.
At a Michael W. Smith show, the drummer was getting dropouts on his IEMs, and I could see that his frequency was loud and clear with no interference near it. This logically led to following best practices of getting his G2 pack’s antenna away from his sweaty hip and replacing his transmitter’s whip antenna with a paddle to increase gain. Problem solved. Without IWx, a lot of time might have been wasted looking for an alternate frequency that wasn’t needed and wouldn’t help.
Like a rear-view mirror, IWx doesn’t make better drivers, but by increasing awareness of what’s around, it helps avoid problems. Everyone knows you should never have to use your spare RF. For about the price of a spare RF unit, IWx can help make sure of it.