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Wireless Microphone

Carl Blare's picture

The opposite of "beating a dead horse" would be gently treating a live horse, so here it is.

In July 2010 this was in Broadcast Engineering Mag

The FCC has proposed new rules that would allow legal, unlicensed operation of TV-band wireless microphones by anyone at powers below 50mW. We are not likely to see these rules adopted for several months. In the meantime, the FCC is allowing operation of wireless microphones below 50mW by anyone on an unlicensed basis, under temporary waivers.
- Mitchell Lazarus - Fletcher, Heald & Hildreth, PLC

NOTE the part about "temporary waivers." I want mine.

A wireless mic is a low power transmitter with a mic attached. Any part 15 station is a low power transmitter with a mic attached. A line input to a transmitter connects other mics to the transmitter, included recordings made from microphones in a recording studio.

All part 15 stations are wireless microphones and here's your waiver. Have fun.

Fly By

Carl,

I suggest you fly that by a communications attorney or maybe a FCC inspector. My experience would say you won't get very far. Yes, you can imagine anything, but that doesn't make it so.

Following your logic (which is circular), if I have a radio station that is broadcasting legally, and broadcasting legally means I am a legal radio station, then I should be able to operate just like the other legal radio stations at 250 watts or more. The only difference being, I don't have a license. But. I'm still legal. And because I'm legal, and a radio station, I should qualify for any special waiver.

Really? You think so. Carl, with all due respect, its time to wake up and smell the coffee. I'll buy.

Marsh Johnson, Sr. - North Bend, Oregon, USA

Black No Sugar

We'd have more than one coffee Marshall Johnson, Sr.

But then, what does the magazine article I quoted actually say?

Carl Blare

FCC NPRM

The article focuses on the government agency process called "Notice of Proposed Rule Making". It's the method the FCC uses to have a public hearing across the country on a single issue. In this way, those folks who have skin in the game can comment and provide direction for the process. This NPRM has all the earmarks of a trail balloon on the part of the government. The waiver is an effort to give cover to the users of the devices in question. I, frankly, would be surprised to see any part of this NPRM become part of administrative law.

The FCC is getting criticized from many corners of the country on their lack of action on the open spectrum free-ed up by TV going digital. TV finally going digital took how many extensions? And this switch was suppose to be mandatory.

Let me say it again, this is wishful thinking at this point. The article doesn't seem to give a deadline for comments. So the issue, and subsequent decision, could be open-ended. Let's not forget the NPRM to establishing a LPAM licensed service is still open with no action before the Commission (many years later). 'Nuf said.

Marsh Johnson, Sr. - North Bend, Oregon, USA

Your Waiver

Don't forget your waiver.

Carl Blare

This is what I've been saying...

The Comtek BST-25 transmits on any frequency between 76-87.8 MHz.

It is now considered a Part 15 device...ANYONE can use it, for any purpose, because it meets the technical criteria in the 'Wireless Microphone Report and Order'. The device must be certificated under Part 74 technical rules, and this one is. It has a line-in XLR input. It has a 'high gain' external antenna. It covers about a solid mile with that external antenna.

I have mine, did you get yours?

"Modulating carriers since the '80s"

Waiting on the Horses Mouth

I have requested info from Comtek regarding permitted uses of the BST-25 transmitter.

No where in the manual does it mention Part 15 use, only that it is designed to operate under Part 74 of the rules.

To read through the BST-25 manual CLICK ON LINK at the bottom of my "Test" webpage. Yet another test for home hosting.

by MRAM 1500 kHz Charter Member - Association of Low Power Broadcasters Chairman - ALPB

Educated Guess

Based on experience with equipment manuals I would guess that Comtek simply hasn't re-printed their manual to clarify any recent changes in the FCC requirements.

Your request for info from Comtek will be interesting.

Carl Blare

Updates...

Heck, the FCC hasn't updated OET Bulletin 63, 'UNDERSTANDING THE FCC REGULATIONS FOR LOW-POWER NON-LICENSED TRANSMITTERS', since February 1996. A lot has changed since then.

Particularly in the so-called 'White Spaces', or unused TV spectrum.

I can't imagine it would be fair to have the FCC busting someone for playing radio station on 87.5Mhz with a Comtek, when they are going to allow your neighbor to stream pornography, and other internet goodies on the exact same frequencies, license free, with higher power. Obviously, your Comtek won't compete. But Part 15 does state that a device cannot cause interference, and must also accept interference.

It sure would be cool to get Comtek's opinion on the matter. If it's pro, it could be a whole new customer base for them. I'm pretty sure my interpretation of the rules are accurate, but you know how FCC regulations can be a moving target at times. Furthermore, it seems that individual FCC enforcement agents can interpret the rules how they want to...usually in their favor to be able to issue a NOUO.

Let's face it...50mW at the output terminals is not a whole bunch of power, and one must follow the technical rules and absolutely use certificated equipment. The potential to interfere with a licensed entity is pretty low.

Research the Wireless Microphone report and order...pay attention to the addition to Part 15.3, and the addition of Part 15.238. The waiver is temporary but the FCC, believe it or not, is working on making these rules under the waiver permanent.

Part 15 of Title 47 of the Code of Federal Regulations is proposed to be amended as follows:

1. The authority citation of Part 15 continues to read as follows:
AUTHORITY: 47 U.S.C. 154, 302, 303, 304, 307, 336, and 544A.

2. Section 15.3 is revised by adding a new paragraph (hh) to read as follows:
§ 15.3 Definitions.
* * * * *
(hh) Wireless Audio Device. An intentional radiator that is used to transmit voice, music or other audio
material over a short distance. Transmissions may be either analog or digital. Data transmissions are not
permitted except for short strings such as recognition codes necessary to ensure the functionality of a
system. Transmission of audio material to the public switched telephone network and private and
commercial wireless systems and networks is not permitted.

3. A new Section 15.238 added to read as follows:
§ 15.238 Operation in the bands 54-72 MHz, 76-88 MHz, 174-216 MHz, 470-608 MHz and 614-698
MHz.
(a) Operation under this section is limited to wireless audio devices as defined in § 15.3(hh).
(b) Operation is limited to locations removed from existing co-channel TV broadcast stations by not less
than the following distances. See §73.609 for zone definitions.
(1) 54.000–72.000 MHz and 76.000–88.000 MHz:
Zone I 105 km (65 miles)
Zones II and III 129 km (80 miles)
(2) 174.000–216.000 MHz
Zone I 97 km (60 miles)
Zones II and III 129 km (80 miles)
(3) 470.000–608.000 MHz and 614.000–698.000 MHz.
All zones 113 km (70 miles)
(c) Specific frequency operation is required as follows.
(1) The frequency selection shall be offset from the upper or lower band limits by 25 kHz or an
integral multiple thereof.
(2) One or more adjacent 25 kHz segments within the assignable frequencies may be combined to
form a channel whose maximum bandwidth shall not exceed 200 kHz. The operating bandwidth
shall not exceed 200 kHz.
(3) The frequency tolerance of the carrier signal shall be maintained within +/- 0.005% of the
operating frequency over a temperature variation of -20 degrees to +50 degrees C at normal
supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated
supply voltage at a temperature of 20 degrees C. Battery operated equipment shall be tested
using a new battery.
(d) The unmodulated carrier power at the antenna input may not exceed 50 mW.
(e) The mean power of out-of-band emissions must comply with the following:
(1) On any frequency removed from the operating frequency by more than 50% and up to 100%
of the authorized bandwidth: at least 25 dB.
(2) On any frequency removed from the operating frequency by more than 100% and up to 250%
of the authorized bandwidth: at least 35 dB.
(3) On any frequency removed from the operating frequency by more than 250% of the
authorized bandwidth: 43+10 log P dB where P is the mean output power in watts.

The R&O waiver also states that Part 74 certificated transmitters must be used under the waiver, as there are no Part 15 certificated wireless audio devices on the market yet.

BTW- I forgot to mention that I did qualify for and acquire a Broadcast Auxilliary (Part 74) license, for 76-88 MHz over a year ago. I wonder if that would qualify me for inteference protection? Nah....not according to the last September's TVBD ruling.

"Modulating carriers since the '80s"

What About Scosche

The Scosche FMT4R FM Transmitter, findable at Walmart for around $10, is FCC Certified and includes frequencies 87.5 to 87.9.

In previous blogs we've speculated that some kind of error must have been made, but under the conditions described by tbone903 maybe Scosche was simply a very early entry into this new landscape.

I've been using 87.7 to get vinyl records from one room to another for digitizing and the quality is remarkable.

This (cross-your-fingers) hopeful news is just in time for Thanksgiving.

Carl Blare

Scosche FMT4R

I do think that was a mistake. If you check out the certification paperwork for the FMT4R,

https://fjallfoss.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=372682&fcc_id='IKQFMT4'

it does not include any frequencies below 88.1. At the time of it's certification, it could only be certified for 88.1 -107.9. It was against the rules to utilize 76-88 MHz.

To be used under the waiver, it must be certified under Part 74 technical rules. To be used presently, Scosche woul have to re-certify the FMT4R. In addition. it must comply with the new Part 15.238. That means that you are not able to use those frequencies within 65-80 miles of an exisitng Ch. 6 TV station (LP of Full Service), depending on which FCC Part 73.609 'Zone' you live in.

I have one of these, and it is an effective unit. I did notice, however, that the local Walmart has replaced them with the newer model which does not include any frequency below 88.1.

"Modulating carriers since the '80s"

Inspecting the Details Further

tbone903 I now come to agree with you that in some odd way the first Scosche was mistakenly outfitted for the lower FM channels.

Moving to another question, I ask for opinions on the curious fact that the FCC, during this rule changing cycle, is placing into Part 15 some of the references to items which also come under Part 74. Does that suggest a migration eventually of Part 74 low power devices over into Part 15? Another clue that this might be true is the present "waiver" not requiring a license, as the previous Part 74 situation did.

Carl Blare

50mw = Part 15?

It does seem that the FCC has made a new class of low power wireless audio devices, able to use the TV spectrum, license free and allow them to operate amongst licensed users in the same spectrum. Similar to what is already Part 15 AM and FM. These new rule changes are supposed to inspire innovation, right? A Part 74 license will still exist to allow qualified licensees (not radio hobbyists) to use higher power output, and offer them some sort of interference protection.

Right now, though, it would appear that utilizing a Part 74 certificated wireless audio device with an output of 50mW and below in the TV Bands, equipment which used to require a Part 74 license, to be operated by anyone, license free will soon be the law of the land. I believe that Part 15, and not Part 74 certification, will be available eventually to any new types of 50mW wireless audio devices, too.

"Modulating carriers since the '80s"

Channel 6 (ab)Used for some time...

Here's a little item I picked up at the local discount outlet store a couple years ago prepackaged under the name GIFTXPRESS. It came wrapped as a present with a bow on it.

The item is sold as a Wireless Heasphone Set; transmitter and headphone receiver. The set operates on two different frequency bands: 86.5 to 87.5 mHz and 88 to 89 mHz. The headphone receiver also receives the regular FM broadcast band (mono only.)

At $3.99 I couldn't pass it up. The instructions state a 20 foot range however with it's 1.5 inch transmitting antenna I could hear it up to 100 feet away using the supplied headphone receiver.

Made in China, the US distributor is Synapse Retail Ventures, 4 High Ridge Park, Stamford, CT. No mention of FCC acceptance.

by MRAM 1500 kHz Charter Member - Association of Low Power Broadcasters Chairman - ALPB

Comtek responds...

I, too, have e-mailed Comtek regarding the unlicensed use of a BST-25 transmitter.

Here is the text of my e-mail, and the reply:

Hi there.

Just curious to know if the new Title 47 CFR Part 15.216 disclosure statement applies to some of your transmitters (BST-25).

As you may know, the Federal Communications Commission has temporarily waived some of it’s rules to enable license-free operation of ‘Core TV Band’ Part 74 (50mW) low power auxiliary transmitters.

I know you are a manufacturer of excellent equipment and I would not like to see your company receive an FCC fine, as a result of this new rule, if it does in fact apply to the BST-25.

Here is a link to the new rule, via Hallikainen.com:

http://louise.hallikainen.org/FCC/FccRules/2010/15/216/

Thanks for the help!

"Modulating carriers since the '80s"

Comtek responds...

I, too, have e-mailed Comtek regarding the unlicensed use of a BST-25 transmitter.

Here is the text of my e-mail, and the reply:

Hi there.

Just curious to know if the new Title 47 CFR Part 15.216 disclosure statement applies to some of your transmitters (BST-25).

As you may know, the Federal Communications Commission has temporarily waived some of it’s rules to enable license-free operation of ‘Core TV Band’ Part 74 (50mW) low power auxiliary transmitters.

I know you are a manufacturer of excellent equipment and I would not like to see your company receive an FCC fine, as a result of this new rule, if it does in fact apply to the BST-25.

Here is a link to the new rule, via Hallikainen.com:

http://louise.hallikainen.org/FCC/FccRules/2010/15/216/

Thanks for the help!

And the response:

Hello,

Thank you very much for your email. It's always nice to have people looking out for us! We do have a lot of loyal customers who have used the BST-25 operating in the 76-88 MHz range for IFB and ENG truck applications. Currently, most of the units that we sell on this frequency band are going to Canada, and this is the only product line that we have on this frequency band. However, at the start of the new year we will post the new required statement regarding this FCC regulation on our website along with information regarding the current uses and applications for the BST-25. Also, for your information, we are currently working on a new product line that incorporates digital time division and multiple access (TDMA) to replace the BST-25 series equipment.

Thanks again for your support, and please let me know if you have any other questions or if I may ever be of assistance.

Best regards,

Jon
-----------------------
Jon Belgique
COMTEK, Inc.

As you can see, the answer is somewhat cryptic, but points toward the answer that would be "Yes, it can be used without a license" , if Part 15.216 does apply.

Guess we'll have to take a wait and see approach, in regard to their website and the uses they will post.

BTW: A Comtek BST-25 system, complete with PR-25 receivers is currently up on Ebay-

http://cgi.ebay.com/ws/eBayISAPI.dll?viewItem&item=190482073301&ssPageNa...

"Modulating carriers since the '80s"

And the reply...

Hello,

Thank you very much for your email. It's always nice to have people looking out for us! We do have a lot of loyal customers who have used the BST-25 operating in the 76-88 MHz range for IFB and ENG truck applications. Currently, most of the units that we sell on this frequency band are going to Canada, and this is the only product line that we have on this frequency band. However, at the start of the new year we will post the new required statement regarding this FCC regulation on our website along with information regarding the current uses and applications for the BST-25. Also, for your information, we are currently working on a new product line that incorporates digital time division and multiple access (TDMA) to replace the BST-25 series equipment.

Thanks again for your support, and please let me know if you have any other questions or if I may ever be of assistance.

Best regards,

Jon

------------------------
Jon Belgique
COMTEK, Inc.

"Modulating carriers since the '80s"

Post happy...

Sorry about that...I originally forgot to include the reply in my first post. Then, I went to edit it, and it timed out (but, now it seems it didn't). After that, completed a new post with the reply.

Have a great holiday!

"Modulating carriers since the '80s"

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