How far will this antenna reach?

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Since before 2010 and the first round of major changes to the radio spectrum landscape, we've shared lots of words about radio frequency issues.  And with continued proliferation of wireless devices, increased use of LED lamps, LED production lighting fixtures, and LED video displays, along with connected-ness of your refrigerator to grocer's ordering systems, and Microsoft's rural broadband initiatives, these are among the most important issues facing users of audio and video equipment today and into the future. And we think that understanding what lies ahead is fun, in a geeky sort of way. 

Our guest columnist Don Boomer is an Applications Engineer at RF Venue. He has worked in Research & Development for Peavey, Sabine and Line 6 over the past 30+ years, and his rock band from his high school days has a song in the Rock & Roll Hall of Fame. 


by Don Boomer, RF Venue

Don3 1 copyIt’s baseball season again and boy does that make me happy.  What does that have to do with antennas?  Well...

I am often asked, “How far will this or that antenna reach”?  An important question for sure, but that’s the wrong way to think about it.  Generally speaking, antennas don’t “reach” out but rather they “catch” what you throw at them (sorry, still thinking about baseball).

Yes, there are directional antennas such as our Diversity Fin and CP Beam that have gain in one direction and rejection in another, which is usually a good thing, but that’s a different topic. Directional antennas will “listen” better for your transmitters than those with little or no gain.  But they are still just catching what you throw at them.  So an antenna’s range is a combination of how strong your transmitter’s signal is and how you are being affected by multipath reflections and the strength of your noise floor.  The primary deciding factor is your CNR (carrier to noise ratio).

If we were to go stand in a cornfield in Iowa (if you build it, they will come) you would very likely find that the range of your wireless mic, that has a manufacturer’s rating of 300 feet, might well do a 1/4 mile.  That would be because there would be little interference (until Microsoft turns on its new Rural Broadband Plan in the 500 MHz range) and almost zero multipath.  There’s just no GMO corn that reflects RF (yet).  It probably also goes without saying that higher quality systems (with tighter front ends) especially digital ones, will perform better than those sub $300 systems I still see clinging for dear life.

So how about active antennas with built-in amplifiers?  Won’t that stronger signal result in more “reach”?  Crank it up to 11?  Sorry to disappoint but in fact it may perform worse.  The boosters on those amplifiers were only intended to make up for  losses in long coax runs and should only be used IF other factors can’t supply enough signal to keep you on the air.

What’s wrong with active antennas you ask?  Well number one, they are active and no amplifier is perfect.

Read more: How far will this antenna reach?


Next-generation Wireless Microphone Systems

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By now, most of you have heard the news that the FCC is phasing out most of the 614-698 MHz portion of the radio frequency (RF) spectrum for use by wireless microphones and television broadcasters.  Something similar happened in 2010 with the 700 MHz spectrum, so by July 2020, 614-698 MHz will no longer be a legal operating range for most wireless microphones.  And in some areas, those changes are occurring right now, and will continue to occur on a known schedule between now and July 2020.

The change to the "700 MHz" band in 2010 was disruptive, but the next round will be even more so.  When these auctions take place, wireless companies like T-Mobile, AT&T, Verizon, etc. buy large swaths of RF bandwidth in order to deliver their services.  Those services include wireless data and voice traffic, Internet of Things (interconnection of business and household devices to the Internet) and may include 5G wireless services that will attempt to give us driver-less cars and more. 

What makes the current repacking even more difficult is that once again, television broadcasters are being moved from yet another portion of the RF spectrum and wireless microphone users are being asked to share even less space since there is no new RF spectrum being opened up in the previous 470-804 MHz range.  So instead of sharing 470-804 MHz with broadcasters like we did until 2010, the RF spectrum for broadcasters and casual users like UHF wireless microphones will become limited to 470-608 MHz, a loss of over half since 2010. 

In response, some companies have opened up the previously popular VHF ranges (169-216 MHz), 900 MHz and 2.4 GHz, but in order to address the reduction of available wireless spectrum, manufacturers like Shure and Audio Technica have also created new systems that allow more simultaneous wireless microphone systems to operate in less of the RF spectrum.  These new radios are more selective and less sensitive to outside sources than ever before.

We believe that these and similar systems will provide the best foundation going forward for reliable wireless microphone use, especially in deployments for multi-venue environments and for medium to large users in house of worship, corporate, event and educational environments. 

The Shure QLXD (from $973) and ULXD (from $1320) systems offer operating densities of up to 60 simultaneous systems, depending on your location, and the 4th Generation Audio Technica 3000 Series (from $549) up to 20 systems per 6 MHz TV channel (up to 40 total).  At the time of writing, we have been told that the new Sennheiser Evolution Series G4 300 and 500 series systems will be generally similar to the Shure and A-T systems just mentioned, but we are yet unaware of those exact specifications. 

As tough as it is to look at another round of replacements for all of you with existing "600 MHz" systems, many wireless microphone manufacturers are offering rebates to help limit your pain and ease you into their systems.  For more information on rebates (generally $50-$500 per channel, depending on the new wireless you select), click here for Shure, here for Audio-Technica and here for Sennheiser.

Or call us with questions.  We have helped our clients replace anywhere from a few to 30, 40, and 70+ wireless microphone systems with new frequency sets compatible for both today and beyond July 2020.  The new RF landscape is tough for users of multiple systems, so please let us know how we can assist you in this transition. 

Shure QLXD, ULXD, and Audio-Technica 4th Generation 3000 Series will serve you well for the foreseeable future, and are as good a decision as you can make at their respective price points.  We expect to be able to say the same about the Sennheiser Evolution G4 300 and 500 series.  


4th Gen Audio-Technica 3000 Series and new 5000 series - what happens with my existing microphones?

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With the recent announcement of the 4th Generation Audio-Technica 3000 Series wireless system and the new 5000 series, we've been fielding lots of questions about whether you'll be able to re-use existing earset and lapel microphones.  Today, we have some answers for you. 

The new 4th Generation Audio-Technica 3000 and new 5000 series wireless systems will be shipping in May with a new Hirose screw-down bodypack connector, so if you have existing lavalier, earset or clip-on microphones, your current microphones will not work with the new 3000 and 5000 series.  That said, we've been told by Audio-Technica today that the AT-CWCH adapter cable ($39) will allow you to use current accessory microphones with the new 3000 and new 5000 series in most cases.

IMG 1241

Read more: 4th Gen Audio-Technica 3000 Series and new 5000 series - what happens with my existing microphones?


Make your wireless systems perform more reliably.

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With the increasing challenges posed by FCC TV channel reassignment, the 600 MHz cell phone service rollout, and the increase of LED stage lighting and LED walls, wireless mic and IEM users will need to squeeze out every last drop of system performance to ensure reliable, drop free performance. This article will try to explain how out-of-band interference can jeopardize the performance of your wireless systems and what you can do to minimize it.

What is out-of-band interference?

Basically it is every signal picked up by your antenna that is not the signal from your intended transmitter. In other words it is stray RF interference, be it electrical motor noise, hash from your lighting and projection systems, assisted-listening system, security radios, comms and your other wireless mics and IEMs.

LED Wall RF Noise.png

LED Wall Interference

Very soon it will also include an audience with new 600 MHz cell phones in their pockets and maybe signals from Microsoft Whitespace devices. Antennas aren't smart and simply shove every signal they receive into the front end of your receiver which directly affects the noise floor which you are trying to overcome. The interference from a high noise floor is likely the single largest external factor affecting the range of your wireless mics.

For your receiver to understand a signal it must be strong enough to overcome the background noise floor.

Read more: Make your wireless systems perform more reliably.


It's too loud!

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Virtually every small and medium-sized church with a band fights the same fight. I've heard it called "platform wars", "volume wars" and similar descriptions, but in most cases the facts are simple -- the stage volume (monitors, instrument amplifiers and acoustical volume of instruments like drums) is simply too loud.  And that additional volume forces the sound system in the main seating area to be even louder and/or worse sounding than it needs to be. 

At my own church, we still fight with this most weekends and we're making progress.  The first step we took was to get as many of our musicians as possible on earphones or headphones, and to eliminate stage monitor speakers.  That cost us less than $1000.  We have some additional steps to take, but let's stick with solving the in-ear monitoring equation for now.  

What we did was to buy a simple headphone amplifier.  Today, let's look at the HA4x4 from Elite Core.  It's $119.99 and can provide up to four users the choice of between 1 and 4 different headphone mixes. 

How do you create a separate mix for ear/headphones?  Most audio mixers have auxiliary mix busses and just like you'd send a feed to a monitor amplifier, you can do the same to a headphone amplifier.  In this case, you can send up to four different mixes so that each musician can hear exactly what he or she wants to hear and at the precise volume they'd like, all without bothering anyone else or adding to the volume level in the seating area. 

Elite Core also makes wired bodypacks with volume control.  The WBP-VC gives the wearer a secure place to plug in the earphone mini-plug and an XLR connector for the connection to the headphone amplifier with a beltclip. Try the Elite Core Prohex-Core-18 at $37.99 to get the cable and volume control you need. 

Combine all of that with a set of earphones from Shure like the SE-215 at $99.00 or ATH-M30x headphones from Audio Technica at $69.00.

Next time, we'll talk about making some or all of this wireless, but we wanted to give you an affordable entry point for reducing stage volume in your facility. 

Let us help design a custom solution to quiet your stage volume today!


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