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[Lee Douglas]

I really did try to search this, but found a lot of conflicting information.  I have a couple of Shure ULXP wireless systems that use their M band.  I've pulled them from my dry rental stock and intend use them only for personal use.  Obviously not this year.  I'm not even sure how to phrase this.  I've heard/know that much of the M band is in the frequency range that has been sold off.  I've also heard that the M band is also capable of tuning to frequencies not included in that sell off and that the main reason I can't/shouldn't sell this equipment in the U.S. is because it is "capable" of tuning to frequencies that are.  Are there frequencies that are still usable in the M band?  Can one of you frequency coordinators give me the straight poop on this?  Again, this is for what has become personal gear.  I'd just like to save a couple thousand in replacement gear, if I can, should I be able to get back to performing again.

[Jason Glass]

I really did try to search this, but found a lot of conflicting information.  I have a couple of Shure ULXP wireless systems that use their M band.  I've pulled them from my dry rental stock and intend use them only for personal use.  Obviously not this year.  I'm not even sure how to phrase this.  I've heard/know that much of the M band is in the frequency range that has been sold off.  I've also heard that the M band is also capable of tuning to frequencies not included in that sell off and that the main reason I can't/shouldn't sell this equipment in the U.S. is because it is "capable" of tuning to frequencies that are.  Are there frequencies that are still usable in the M band?  Can one of you frequency coordinators give me the straight poop on this?  Again, this is for what has become personal gear.  I'd just like to save a couple thousand in replacement gear, if I can, should I be able to get back to performing again.

Hi Lee,

You understand correctly that this equipment is illegal to operate in USA and have mentioned valid reasons why.  And that's true whether it's personal or professional use.  You should not ever power them on in USA again.  You can list them on eBay and use the listing's country restrictions feature to assure that USA buyers can't bid or purchase.

Please see the attached screen shot.  The lower 1 MHz of the M bands (662 to 663) MHz is not used by cellular band 71 and fits inside the duplex gap.  However, their FCC ID is indeed now invalid for the reasons you mentioned, and the devices are entirely prohibited.

[Lee Douglas]

Thanks for the clarification, Jason.  I'd gotten my information from somebody I'd considered somewhat knowledgeable, but not quite know the difference between "usable" and "just haven't gotten caught yet" knowledgeable.

Switching gears, I now have to replace this gear.  I bought this equipment new and early in its life cycle and it's served me well.  I've used it all over, mostly in the western U.S. and I've gotten my money out of this gear.  I really liked its frequency agility and had always been able to find an open frequency either via site coordinators, checking a chart or sheer dumb luck.  What is would be it's modern day equivalent? 

[Russell Ault]

[...]
Switching gears, I now have to replace this gear.  I bought this equipment new and early in its life cycle and it's served me well.  I've used it all over, mostly in the western U.S. and I've gotten my money out of this gear.  I really liked its frequency agility and had always been able to find an open frequency either via site coordinators, checking a chart or sheer dumb luck.  What is would be it's modern day equivalent?

In my mind, Shure's current-model replacement is QLX-D. As I understand it, ULX-D was originally intended to be a ULXP replacement, but through the development process the feature set (and price) increased to the point that was more inline with the UHF-R equipment (which, at the time, didn't have a digital successor). As a result, ULX-D started to be marketed as a UHF-R replacement, and QLX-D (basically a somewhat stripped-down ULX-D) was developed to fill the gap left between SLX (now SLX-D) and ULX-D. Depending on what features you're after (and especially if you're only looking for one or two channels) SLX-D is worth looking at too.

If you're not married to Shure (and be aware that your current handheld capsules may or may not be compatible with a digital TX) Sennheiser's analogue G4 systems aim for roughly the same market segment.

-Russ

[Brian Jojade]

Technically per the guidelines, anything that's even CAPABLE of working in the banned frequencies is illegal, even if you never tune them to those frequencies.

Now, in reality, if you're a competent operator and know enough not to be stupid, there's pretty much no way that you'd get caught having a pice of gear that COULD work in those frequencies if you never tune them that way.  The only way would be if an inspector came in and physically looked at the gear in question.  Additionally, on some of Shure's products, you can get firmware updates that block out the banned frequencies.  This doesn't change the FCC ID sticker on the product, so even an exterior inspection may not be enough to know if the equipment is OK. The odds of that happening for a small time operator are pretty much next to nothing.

As rental stock, clearly you can't count on operators being competent, so definitely don't rent it out.  If you're using it on your own and are smart enough never ever to accidentally tune to a banned frequency, you're probably fine. If you want to follow the absolute letter of the law, no. But if you're ok with spirit of the law, then go for it.

[Russell Ault]

[...] If you're using it on your own and are smart enough never ever to accidentally tune to a banned frequency, you're probably fine. If you want to follow the absolute letter of the law, no. But if you're ok with spirit of the law, then go for it.

Well, except for the desens. Cellphone radios at max output are ~3 watts, and the input filtering of an M-band ULX RX isn't likely going to do much against a 3 W signal less than 1 MHz away from the intended carrier (which leaves its TX at least 20 dB lower). Plus, operating so close to the bottom of the range means that the input filtering might be attenuating your TX's carrier more than a cellphone signal.

Even if using them was legal I wouldn't want to rely on them.

-Russ

[Scott Holtzman]

Well, except for the desens. Cellphone radios at max output are ~3 watts, and the input filtering of an M-band ULX RX isn't likely going to do much against a 3 W signal less than 1 MHz away from the intended carrier (which leaves its TX at least 20 dB lower). Plus, operating so close to the bottom of the range means that the input filtering might be attenuating your TX's carrier more than a cellphone signal.

Even if using them was legal I wouldn't want to rely on them.

-Russ

Have you had any luck explaining things like this to down market acts?  I am not talking about bar bands, regional touring acts, heritage acts of people you may have heard of if you are good at one hit wonders even a disco queen from the late 70's.  Sometimes I was hired by the band, other times was working at a venue, couple of times at serious weddings.  I have gotten reactions ranging from anger, "screw the government", my favorite "never had any issues with it".  Rational discussion seems to make it worse.  I have had competition tell me that I have lost business because I criticized the acts tech.  Basically I keep my mouth shut and that seems wrong too.  Just wondering if you have some tact that you use to diffuse defensiveness and start a reasonable dialog?

[Henry Cohen]

Now, in reality, if you're a competent operator and know enough not to be stupid, there's pretty much no way that you'd get caught having a pice of gear that COULD work in those frequencies if you never tune them that way.  The only way would be if an inspector came in and physically looked at the gear in question.  Additionally, on some of Shure's products, you can get firmware updates that block out the banned frequencies.  This doesn't change the FCC ID sticker on the product, so even an exterior inspection may not be enough to know if the equipment is OK. The odds of that happening for a small time operator are pretty much next to nothing.

. . . If you want to follow the absolute letter of the law, no. But if you're ok with spirit of the law, then go for it.

Um, no.  One of the rules changes, and the reason Shure doesn't have a firmware upgrade for the ULXP, concerns the spectral mask and out of band emissions; it's far tighter now (it matches the ETSI standard for wireless microphone emissions published about five years ago) to protect the LTE uplink. Older hardware generally can not meet the technical rules and has a greater chance of causing interference, hence the reason a firmware change that merely locks out specific tuning ranges is insuffiicient to protect the licensed services. Network carriers constantly monitor the RF noise floor in their uplink bands for interferers, and they're quite good, and fast, at finding those intereferers.

In the only terms that matter, no one can operate older equipment, that hasn't received an OEM firmware upgrade and a new FCC ID number, in the 600MHz duplex gap or in 614-616 MHz. Period.

[Henry Cohen]

. . . Cellphone radios at max output are ~3 watts, . . .

Not anymore, for handhelds at any rate. With the advent of LTE, modern portable phones' max RF output is generally around 800mW, and carriers try to keep the phones at <100mW (closer to 10mW in urban areas) to keep the noise floor reasonable. The soon to be exception will be those phones that operate on Band 14 (public safety's FirstNet system), and then only when the one is operating on that band. IIRC, the max RF will be 2W for handhelds.

[Russell Ault]

[...] Just wondering if you have some tact that you use to diffuse defensiveness and start a reasonable dialog?

Hopefully someone else will have a better answer, but the truth is that my little niche doesn't often intersect with the kinds of acts you're describing. I'm typically either working as a venue technician or (less commonly) directly for the artist. In the former case I dutifully discharge my obligations as an employee by bringing my observations to the attention of management—and then let the chips fall where they may (and in the latter case, mostly because of the former case, I can afford to be picky about my clients—and they know what they're getting).

Even when I do find myself sharing a venue with that kind of act, the most common RF complaint I have is that the local MI chain inexplicably (at least to me) didn't try to upsell on the 2.4 GHz rental gear. I feel like it's been at least a couple of years since I had to tell a group that their once-legal equipment is no longer thus (although I know my early-warning observations have resulted in thousands of dollars of trade-in-related sales to both Sennheiser and Shure; to whoever got those commissions, you're welcome!). I have seen a (mildly terrifying) direct-from-eBay "Evolution" (but notably not "Sennheiser") IEM set that...should not have existed; the brief conversation with the owner of the unit went about as well as you'd expect for someone who was willing to knowingly buy knock-off RF equipment on eBay (and, as a venue employee, it mercifully ceased to be my problem as soon as my supervisor was made aware of the situation).

Where I live, "the market" is also on my side. Despite a 1 million+ metro population there are exactly 5 UHF TV transmitters within reception range, so wireless microphones are often seen as basically bullet-(and idiot-)proof. Conversely, the mobile carriers around here often spin up new frequencies as quickly as they can (our population density and service demand characteristics make us excellent RF guinea pigs) so the difference between "legal" and "not legal" is often pretty darned stark. (Every once in a while I'll find myself looking at a sound system as a personal favour to someone; usually the "you should stop using that right away because it's illegal" is responded to with "oh, we don't use it anymore, it stopped working all of a sudden a little while ago". Then all I have to do is give them the bad news that all the trade-ins have ended!)

Not anymore, for handhelds at any rate. With the advent of LTE, modern portable phones' max RF output is generally around 800mW, and carriers try to keep the phones at <100mW (closer to 10mW in urban areas) to keep the noise floor reasonable. The soon to be exception will be those phones that operate on Band 14 (public safety's FirstNet system), and then only when the one is operating on that band. IIRC, the max RF will be 2W for handhelds.

Ah, that's good to know; I'll go back to worrying about LMR desens instead.

-Russ

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