A lot of our dealers are asking about the benefits and drawbacks of UHF/TV-Band (470-698 MHz) wireless mics versus the newer 2.4 GHz digital wireless systems that have come on the market. Indeed, there have been quite a few in recent years from the early Sabine 2.4GHz system, to the newest whizbang tech from Line 6 and intercom manufacturers like ClearComm.
There seems to be a fair amount of misinformation about this topic, so we’re hoping to use this post to bust a few myths and hopefully present some unbiased info on each platform--since we believe they both have their place in professional live and installed sound. [Full disclosure: [RF Venue](http://www.rfvenue.com) manufactures remote antenna systems for both UHF and 2.4 GHz systems, so we have no real horse in this race]
First off, a common misconception is that the 2.4 GHz band is less crowded than UHF. But guess what? They’re both crowded! 2.4 GHz is less busy only when looking at other wirelessn 2.4 GHz mic systems or over the air TV stations, but not if you take into account all the wireless access points (WAPs) and routers that crowd the 2.4 GHz band in densely populated areas. New TVBDs are coming to the UHF white spaces and the density of TV stations in places like Los Angeles and Manhattan makes reliable wireless audio in the UHF band pretty daunting today. When UHF white spaces are sold off there will be even less RF real estate for wireless mics in that band.
The other misconception concerns operating range. There seems to be an idea that UHF goes long and 2.4 GHz falls short. For most bread and butter 4-8 channel mic systems, reliable operation within 200 feet is more than adequate, a range which both bands easily achieve. Technically, the UHF band has longer range and better propagation outdoors and through solid objects, but the difference is mostly negligible since both frequency bands are fairly power limited as dictated by the FCC. In our experience, people have a tendency to overestimate how much operating range they actually need, overcompensating with higher gain system components and output power settings.
So if range is not as big of an issue for most systems--and both bands are in fact pretty crowded--what are some real differences?
- Transmission line loss: Transmission line loss is the signal lost over coaxial cable runs. 2.4 GHz is very lossy compared to 600 MHz. With 100' RG8X coax cable 2.4 GHz loses 21.5 dB while 600 MHz loses 9.7 dB. So if you need to remote antennas or racks, you need very low loss coax cable like LMR400, in-line amplification to boost RF signals ahead of the receiver, or a RFoF system. Higher gain 2.4 GHz antennas like the CP Beam can offset some of this line loss, but the higher the operating frequency of your wireless system there will always be higher transmission line loss.
- Channel Count: UHF band wireless mics are able to accommodate more wireless channels than 2.4 GHz. It is difficult to fit more than 12 channels in 2.4 GHz. Wi-Fi uses a digital protocol that aggressively and rapidly switches frequencies, making it much more difficult for other devices to compete for spectrum and limiting the total number of devices that can reliably fit. Plus, there is simply less spectrum available. About 80 MHz is up for grabs in 2.4, while more than 200 MHz is available in UHF.
- Procurement and Configuration: With 2.4 GHz there is a single SKU to rule them all, worldwide. As manufacturers we see this alone as huge motivation for mic makers to move to unlicensed 2.4 GHz, and can understand why system integrators and touring companies see a lot of benefit on procurement and configuration with a standard set of tools and a universal setup procedure wherever the system is deployed.
- Sound Quality: We’re not going out on a limb on this one since we’ve heard excellent sound and atrocious sound from both platforms under different circumstances (and mixes!), so we’ll leave that one for the golden ears crowd.