Wisycom Wideband/Narrowband and Linear Modes — Demystified

Two powerful features, often mixed up but actually completely separate

If you’ve spent time in the world of wireless sound, you may have come across two mysterious settings on Wisycom transmitters: Wide/Narrow-band and Linear (L) mode. They are sometimes thought of as being connected, but they’re not. Think of them as two independent tools that each tackle a different part of the RF puzzle — one about how much space your signal takes up, the other about how cleanly multiple signals coexist.

1. Wideband vs Narrowband — How big a “lane” your signal needs

Every wireless microphone takes up a bit of spectrum, just like a car taking up a lane on a motorway.

• Wideband mode is the normal lane width — roomy, reliable, and standard for most radio-mic systems (occupying roughly 200 kHz).
• Narrowband mode squeezes that lane down to half the size — about 100 kHz — so you can fit twice as many cars (channels) on the same stretch of road.

When set to narrowband mode your receiver is only looking through a smaller “window” on the spectrum, so it lets in less background noise. The result is a cleaner signal with more range, without significantly affecting sound quality — especially with the excellent ENS compander used in Wisycom’s latest transmitters such as the MTP60, MTP61 and MTH610.

From a technical standpoint, halving the occupied bandwidth cuts the receiver’s noise power in half, which delivers about a 3 dB improvement in signal-to-noise ratio. That’s roughly equivalent to doubling transmitter power and gives about a 40% increase in line-of-sight range. To use narrowband, both transmitter and receiver must support it in hardware — compatible receiver models include the MCR54, MPR52, MPR50 and MRK980.

2. Linear Mode — Keeping the neighbourhood clean

Now for a completely different concept: Linear mode.
This one’s all about how transmitters behave when they’re close together.

When several transmitters sit near each other, their signals can mix inside any circuit that isn’t perfectly linear — a bit like two singers harmonising badly and creating unwanted notes. Those “extra notes” are called intermodulation products, and they can pollute big sections of spectrum, making other channels unusable.

The term comes from inter (Latin for ‘between’) and modulation (signals modulating one another). It happens in any non-linear device excited by RF energy — amplifiers in antennas, receiver front-ends, or even transmitters themselves when stray RF from nearby units couples back into their own antennas. The result can be a dense web of spurious frequencies that sterilises large chunks of spectrum.

Traditionally, this meant you had to design complex intermod-free frequency plans, carefully spacing channels to avoid these unwanted products. If you want a deeper dive check out my blog on intermods here.

Linear mode changes the game.

Linear mode changes the game.

By running the transmitter’s amplifier in a cleaner, more linear state, Wisycom virtually eliminates what’s known as reverse intermodulation — the type caused when RF energy travels back into another transmitter’s output stage. With Linear mode enabled, you can simply tune your channels at evenly spaced (or “striped”) frequencies without all the intermod maths.

A quick rule of thumb:

• In wideband, keep a minimum of 400 kHz spacing between channels.
• In narrowband, you can go as low as 200 kHz (ideally 250 kHz if you’re not pressed for channel count).

Those spacing figures ensure that transmitters’ occupied bandwidths don’t overlap and that receiver filters have enough “guard band” to reject adjacent channels.

You’ll find Linear power options in compatible transmitters menus marked with an “L” before the power level — for example L10 or L20.

It’s crucial that every transmitter operating within the same coverage area is operating in Linear mode. One rogue unit not set correctly can pollute the spectrum for everyone else. The same applies to visiting ENG or second-unit crews using the same frequency band.

Because the amplifier runs with higher quiescent current to maintain its linearity, Linear mode uses a little more battery power than the standard settings. The effect is modest, but worth bearing in mind — a fair trade-off for the much cleaner spectrum it provides when high channel density is required.

For this to work, your entire RF chain — antennas, active splitters, matrices, fibre links and receivers also need to meet the same performance standards. A single weak link can undo all the benefits. Fortunately, Wisycom’s ecosystem, including its RF-over-Fibre systems, is designed from the ground up to support true linear operation.

Putting it all together

To recap:

• Wide/Narrowband decides how much spectrum each channel occupies.
• Linear mode determines how cleanly multiple transmitters share that spectrum.

They’re independent but complementary. Used together, they allow you to pack more robust wireless channels into the ever-more-congested spectrum while maintaining crystal-clear performance.

If you’d like to dig deeper or get help setting up your system, drop me or the Raycom team a line — we’re always happy to help.

Pyers Easton
Raycom Ltd