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White Space Worries? Not Anymore with Zaxcom ZHD

September 26, 2017

By Colleen Goodsir, Zaxcom

White Space Worries? Zaxcom ZHD modulation has you covered.

If you haven't heard by now… the Federal Communications Commission (FCC) held an incentive auction to repurpose the 600 MHz UHF TV band (614-698 MHz) which directly affects sound recordists, stadiums, venues, theaters, churches and others using wireless technology.

In the coming months, wireless microphones, in-ear monitors, IFB systems and intercom systems will be forced to adapt to new requirements set by federal regulations prior to the July 13, 2020 deadline. Afterward, only a small portion of the 600 MHz UHF TV band will be available for use.

Thanks to Zaxcom ZHD modulation, the shrinking wireless spectrum just got a whole lot bigger.

What is Zaxcom ZHD modulation?

Zaxcom High Density (ZHD) modulation is technology that increases the number of channels in the wireless spectrum. There are five different modes to choose from based on your application: Stereo, Mono, XR, ZHD96, and ZHD48.

Finding out how many additional channels you’ll receive with ZHD modulation to any MHz range is simple using a quick formula:

  • Stereo/mono/XR: (MHZ range x 2)-1
  • ZHD96: (MHZ range x 5)-1
  • ZHD48: (MHZ range x 10)-1

In order to protect against overlapping channels, we subtract 1 to the MHz range. Here are a few examples:

  • With ZHD48 selected in a 4 MHz range (653-657 MHz): (4 x 10)-1=39 channels
  • With ZHD96 selected in a 2 MHz range (614-616 MHz): (2 x 5)-1=9 channels

It’s that simple! Now you can face the shrinking wireless spectrum head-on with Zaxcom ZHD modulation.

What Zaxcom products carry ZHD?

No matter the application Zaxcom has a solution for your production sound needs.


TRXLA3 or ZMT3 – small and durable Digital Recording Wireless bodypack transmitters for any situation
TRX743 or ZMT3-HM – plug-on style Digital Recording Wireless transmitters for boom or ENG applications
ZMT3-Phantom – a very compact Digital Recording Wireless transmitter for a boom
ZMT3-HH – a versatile Digital Recording Handheld microphone that transmits wirelessly or through a hardwired connection


RX-12R – a rack mountable wireless receiver ideal for studio, network and broadcast applications
RX-12 – a 12 channel wireless receiver for your sound bag or cart
QRX300 – a single channel wide-band dedicated ZHD48 modulation receiver
QRX235 – a block-specific four-channel wireless receiver with QIFB (ZaxNet remote control)
QRX200 – a wide-band four-channel wireless receiver
RX200 – a wide-band two-channel wireless receiver

Internal Recording Included!
More tech for thought, Zaxcom Digital Recording Wireless come equipped with built-in recording capabilities where encrypted audio is recorded to a microSD card. It’s perfect when you need a backup recording or if run into radio frequency (RF) interference.

FCC Incentive Auction In-depth
Want to learn even more about the FCC auction and how ZHD modulation can fit into your workflow? Zaxcom has published an extensive overview HERE.

Shop Zaxcom
For Dale Pro Audio's selection of Zaxcom wireless products, click HERE.

Colleen Goodsir is the Director of Sales and Marketing for Zaxcom.

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