FreqOut
UHF Spectrum Survey for Sound
Free · Designed for iPad. Not verified for macOS.
Survey a venue's UHF band before deploying radio mics. Real hardware, real data — green chips mean go, red means avoid.
FreqOut is a UHF spectrum survey tool for production sound engineers. Before you unpack a single radio mic, sweep the venue and see exactly what is already occupying the band.
WHAT IT DOES
Connect an RTL-SDR dongle to any Mac, PC, or Raspberry Pi running rtl_tcp, and FreqOut sweeps your chosen frequency range over Wi-Fi, stitching the results into a single spectrum display.
Run multiple passes and a max-hold trace builds up the worst-case occupancy picture since you started.
BUILT FOR RADIO MIC WORK
The UK band plan is built in. Channel 38 (606–614 MHz, the Ofcom PMSE shared licence), 823–832 MHz, and 863–865 MHz are highlighted automatically. TV channel boundaries are labelled across the full UHF range so you can see at a glance what is broadcast and what is available for radio mics.
READS ANALOG AND DIGITAL TRANSMITTERS CORRECTLY
Analog transmitters show as narrow spikes. Digital transmitters (Audio Ltd A10, Zaxcom, Shure Axient Digital) spread ~200 kHz wide and read ~20 dB lower per bin — a standard power meter misses them.
FreqOut scores occupancy by integrated channel power, so a digital block is detected and ranked correctly alongside any analog carriers. Nothing hides.
CLEAR FREQUENCY RECOMMENDATIONS
Colour-coded chips give a per-channel verdict: green for clear, amber for caution, red for busy. An Avoid list ranks occupied frequencies by channel power so you know exactly what to steer around when coordinating.
FM harmonic ghost images from the tuner are tagged (FM?) so you can tell tuner artefacts from real interference.
THE PI RIG — SURVEY ANYWHERE
A Raspberry Pi with the dongle can broadcast its own Wi-Fi hotspot. Power it from a USB battery pack, join its network from your iPhone or iPad, and FreqOut works at any venue with no Mac, no venue Wi-Fi, and no internet required.
WHAT YOU NEED
An RTL-SDR dongle (NESDR SMArt or similar) and any Mac, Windows PC, Linux machine, or Raspberry Pi to run rtl_tcp. Setup takes a few minutes; the built-in user manual walks through every back end.
FreqOut is a survey tool, not a monitor — power spectra only, no audio demodulation, no transmitter programming. Designed for the sweep you run before the gear comes out of the cases.
v2, with direct USB connection to the dongle from an M-series iPad — no Pi rig required — is in development pending driver authorisation.
---
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
bug fixes and minor graphics improvements
The developer, Keith Tunney, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Keith Tunney
- Size
- 2 MB
- Category
- Productivity
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 KeithTunney