Wireless Mic Limitations

mellinger

Member
Hi Everyone,

I work at a school in South Korea and up until recently, I was able use wireless mics on the 500mhz band and the 900mhz band. However, we are now only able to use the 900mhz band.

That band is 925mhz to 937. So it's quite a narrow band.

So currently we use 20 microphones. 12 shure ULX systems that were on the 500mhz band and 8 JTS brand mics that are on the 900mhz band. Because we can no longer use the 500mhz brand, we need to change over our mics.

So, finally to my question. How realistic is it, to still keep a 20 receiver system within such a narrow band? So many mics that I find say that they optimally work with only 8 to 10 receivers on the same band.

My JTS mics can change to different frequencies within 25 mhz. So you can make very narrow tweaks on the frequency.

With that said, do you think I could potentially get up to 20 of the receivers running together with the 900mhz band without interference? Our school is fairly isolated and mostly has apartments around it, and up til now have not had interference issues.

Also, does anyone have software recommendation for choosing frequencies to avoid intermodulation (when dealing with 20 mics)?

All this may be too much for the narrow band we are allowed to use here, but thought I'd ask.

On a 2nd note, they do sell 5.8ghz wireless mics here from a taiwanese company called MiPro that I've thought could be an option. Does anyone have experience with 5.8ghz? Only worry I have is possible wifi interference.

Thanks for taking the time to read this.
 
It's been a few years since I've been active in the audio game, but I'll try to answer this the best I can before a current pro chimes in.

Yes, 12 MHz is a very narrow band to operate in. I don't think this is an issue for the newer digital systems though, and I'm sure the big brands make digital systems suitable for your approved frequency range. I'm quite sure the discontinued ULX systems cannot run 20 systems in only 12 MHz.

Shure probably still has WWB (Wireless Workbench) software which can be used for frequency coordination. It's almost a must to use the coordination software to prevent intermodulation issues unless you're using a completely similar system (ie, all 20 systems of the same manufacture and model, and you could use their coordination tables or possibly automatic frequency coordination/selection tools). This is probably going to be more prevalent in the newer systems than anything pre-circa 2015ish.

These folks (https://www.professionalwireless.com/intermod-analysis/) make a really really good software for coordinating frequencies. I had an old license of it from back in the early 2000s, but I didn't have a use for it so never renewed it, and I'm pretty sure it's obsolete. It's probably not worth it to by a license for one venue like this, since other tools are out there, but software does exist for stuff like this.

All that said, I don't know what the frequency availability situation is in South Korea. Do they have over-the-air TV there? Is there a dedicated band you can operate in for unlicensed users? Do you need a license to use UHF mics there?

Best of luck. This board is filled with lots of smarties who can guide you in this journey!
 
Hi Everyone,

I work at a school in South Korea and up until recently, I was able use wireless mics on the 500mhz band and the 900mhz band. However, we are now only able to use the 900mhz band.

That band is 925mhz to 937. So it's quite a narrow band.
I did a quick google, it looks like the lower UHF band that was previously accessible is now a licensed band requiring a concert hall license. What are the barriers to entry to getting that license? All the information in English I can find just mentions this license but the specifics are all in Korean.

So, finally to my question. How realistic is it, to still keep a 20 receiver system within such a narrow band? So many mics that I find say that they optimally work with only 8 to 10 receivers on the same band.
I can only make around 13 freqs work out in that range using traditional analog wireless. I can make 21-28 work out using top of the line digital wireless (AD4Q)

These folks (https://www.professionalwireless.com/intermod-analysis/) make a really really good software for coordinating frequencies. I had an old license of it from back in the early 2000s, but I didn't have a use for it so never renewed it, and I'm pretty sure it's obsolete. It's probably not worth it to by a license for one venue like this, since other tools are out there, but software does exist for stuff like this.
A lot of the high level RF folks are transitioning from IAS to soundbase.app
 

Users who are viewing this thread

Back