Mod Squad: Evation Technologies RF Nomad

CV Control Over Shortwave Radio
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CV Control Over Shortwave Radio
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Radio is a popular sound source for modular users. But while Buchla and ADDAC System, with the 272e and ADDAC102 respectively, offer voltage control over the FM band, the shortwave bands have gotten little attention. Evaton Technologies recently heeded the call with an 8HP Eurorack module, the RF Nomad ($176).

If you’re looking forward to sequencing easily from station to station with the RF Nomad, you’re likely to be disappointed—shortwave surfing doesn’t work that way. But if you like the heterodyning whistles and tones produced by ham radios as well as a colorful noise, and you would like to have those sounds under voltage control, then you’ve come to the right place.

The RF Nomad is a single-sideband shortwave receiver that is factory- tuned to pick up the 9.6 to 10.0MHz area of the spectrum. While that’s a tiny slice of the shortwave range, the company says that offering a wider range would make it more difficult to focus in on stations. With slight adjustments behind the panel, you can, however, alter the center frequency to get a different range of the shortwave spectrum.

Unlike FM-receiver modules, the RF Nomad requires an external antenna to capture signals and comes with a 5' model that plugs into the panel’s coaxial jack. However, I suggest you spend the extra $12 for the company’s 25' antenna; you’ll need as much wire as you can get.

The module’s input RF Gain control boosts the signal from the antenna, while the Audio Gain control increases the strength of the decoded signal before the output. The CV input, which controls receiver tuning, has an attenuator and accepts bipolar signals— an LFO, EG, stepped or randomized CV, and even audio works great. For more performative control, I used a touchpad on the Make Noise Pressure Points to sweep the module’s CV input to get theremin-like results. Going a step further, I used the Soundmachines LP1lightplane’s CV looping capabilities to create repetitive modulation patterns.

In general, the RF Nomad’s output is brimming with broadband noise, particularly when you have the RF Gain and/or Audio Gain controls set at a high level. Although the manual suggests using a bandpass filter to ferret out interesting bits from the noise, I had the best success using a notch filter (in this case, provided by a WMD Micro Hadron Collider). The trick is to then work the frequency and cutoff controls to find that sweet spot where the RF Nomad’s broadband noise is lowered enough for shortwave signals to pop out. Although that can be a moving target, it’s an equally exciting aspect of the RF Nomad. Once you find something you like on the radio, you can shape it by sweeping your external filter’s frequency, either manually or with an LFO or stepped/randomized CV.

Unfortunately, shortwave listeners are at the mercy of several variables— location, atmospheric conditions, and the sunspot cycle, among them. Even with a 25' antenna, solidly tuning in stations on any shortwave radio can be a challenge. If the conditions are working against you, it’s unlikely you’ll get a recognizable station on the RF Nomad. In that case you can wrap the antenna around some home electronics and use it as an inductor to capture electronically generated sounds for processing through your modular. With an open mind (and some patience), the RF Nomad will reward you as a rich sound source.