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Topics - tybee

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As we all know, the Part 15 realm encompasses far more than just intentional AM and FM broadcasting; The most predominant use of part 15 today is undoubtedly Wi-fi broadcasting.. and/or perhaps our cellphones.

I recently, (while trying to track down some 1938 FCC dockets) had a conversation with Michael Marcus, the FCC engineer who was largely responsible for creating the WIFI band. During our conversation he had mentioned that Part 15 was worth more than $90 Billion a year today...

 That stuck in my head, and though that tidbit of info has little to do with my specific research of Part 15 LPAM history, I was curious if that number was accurate (90 Billion is unfathomable number to me - like the number of sand crystals on a beach!) - While I did not really doubt his knowledge, further conformation is found at the NTCA website (which somehow is an acronym of The Internet & Television Association):

"A new report from the Consumer Technology Association (CTA) estimates that Wi-Fi and other unlicensed wireless technologies generate $95.8 billion per year for the American economy in technology sales alone...

..So what is unlicensed spectrum? The term refers to the radio frequencies set up to drive innovation—they are open to any use and by anyone, as long as devices follow certain technical rules. Decades ago, the US was the first country in the world to create unlicensed spectrum and it was one of the best decisions the FCC ever made..."


Particularly liked their definition of the part 15 spectrum too (shown above.

You know it's kind of interesting.. The very first part 15 devices ever sold were AM transmitters (phono-occilators), they came on the market sometime around November of1938.. about a month before part 15 was created.

So technically they were illegal. The Part 15 rules allowing for intentional broadcasting were literally created to accommodate the legal use of those tinytransmitters, as well as for the upcoming Philco remote control - which went on the market slmost immediate after Part 15 was inacted, as did also electric garage door openers.

But the original part 15 device was LPAM,

Part 15 in general is a multi-billion dollar industry today (I think 90 billion has been quoted). If it hadn't of been for a little 1938 AM transmitter with a range hardly capable of crossing the room over 80 years ago, we might not have things like wifi, cellphones, remote controls and what have you today.

I still haven't pinpointed exactly who was manufacturing phono-occilators in 1938, but they were on the market.

I was just reading a 2014 article about the FCC opening up the 600mhz band (part 15) for tv at https://www.fiercewireless.com/tech/fcc-supports-more-unlicensed-use-tv-600-mhz-bands - - I realize its completely off-topic in regard to AM and FM broadcasting, but the article made mention of something I never knew that I found interesting...

"...Commissioner Jessica Rosenworcel pointed out how three decades ago, the commission was looking at what to do for airwaves that were designated for industrial, scientific and medical (ISM) uses. The spectrum once deemed as "garbage bands" ultimately ended up being spectrum where Wi-Fi was born. Today, nearly one-half of all wireless data connections in the U.S. are offloaded onto unlicensed spectrum..."

What struck me is that control of ISM emissions is exactly the primary reason prompting the creation of part 15 in 1938 (it was not as legend has it, because of the invention of the Philco "magic-eye" remote control, although that and phono oscillators entering the market did play a small part in the decision). I also had no clue that wifi arose from utilizing freqiency bands which had prevously always been considered as completely useless for intentional broadcasting.

Part 15 AM and FM Station Operation / Music licensing concerns
« on: September 26, 2022, 1555 UTC »
I realize probably 95% of part 15 hobbyist don't bother with paying music royalties, and in certain cases it's not even a requirement. But for those utilizing part 15 as a mean of public performance and are concerned about being 100% legal, then a reliable source of information on the subject can be reviewed in the publication "Use of Copyrighted Music on College and University Campuses" (Campus Stations are part 15 operations too)

Part 15 AM and FM Station Operation / What has become of NOUOs?
« on: September 26, 2022, 1403 UTC »
About 2 years ago I noticed there had been only 1 AM NOUO since November 2016, which was odd when you consider there had been an average of 6 to 12 NOUO citations per year since 2002. (There's a list of them at http://part15lab.blogspot.com/2014/04/nouo-notices-of-unlicensed-operation.html

 I hadn't looked in awhile, so today decided to comb through the FCC database http://transition.fcc.gov/eb/FieldNotices/ and discovered two curiosities; It used to be that you could search back 10 years, but now you can search back as far as the year 2000.. But only up to the year 2019 - There's nothing after 2019! Not for AM or FM!

Did I miss something? Has the FCC quit making this information public knowledge    since the pirate war began or something?

In this video this guy explains why this cheap laptop is good for Ham radio and a good alternative to a rasgberry pi....

Cheap $60 laptop Actually Good for Ham Radio

There's a couple other videos praising this as good for hams to. I'm not really familiar with all that but I'll tell you what interest me about this budget laptop.. I'm moving my transmitter to my sailboat again. This laptop runs and will charge with a direct 12v connection, it comes with Windows 10 Educational Pro installed but you can install Windows 7 (better for using Zara) or Linux if you want. it's not fast but it's very efficient on power draw, which is important when running solar power. One commenter said it was drawing only 5watts, but I doubt that's right,, From it's internal battery it can run up to 9 hours on a charge (again I doubt that claim, nevertheless the claim is draws a fraction of the energy a more powerful PC would.. And of course it's very cheap. But you apparently can't get it for $60 anymore, now it's closer to $100 (free shipping Amazon, Walmart, Ebay) Still a bargain.

An interesting and/or entertaining summery of part 15 cases as told by the FCC in their Annual Reports between 1939-1960

 - As a result of the increased use of many different types of low-power radio frequency electrical devices for alarms, phonograph -record -playing and remote- control purposes, an informal engineering conference was held at the Commission's offices in Washington on September 19 , 1938 , for the purpose of considering proposed rules and regulations governing their operation....
 ...The rules and regulations were tentatively adopted by the Commission. The tests of the apparatus made by the Commission's field offices have indicated that if the rules and regulations are strictly complied with the devices may be used without causing interference to established radio services.

A study was instituted to reclassify and to adopt rules for each class of radio frequency generator now operating under the low power rules, such as phonograph oscillators, remote control devices, and college and utility carrier systems. The rapid increase in the number of such devices since the war, and their more varied applications, have made such action necessary....

...A toy transmitter placed on the market during the Christmas season was tested and the field intensity was found to be within the requirements of the low-power rule."

 Page 146 --
"Unlicensed operation....
A wave of unlicensed broadcasting by teen-agers resulted from radio mail order houses and popular magazines advertising low-power radio communication kits intended for operation without a license. These "do it yourself" sets radiated excessively and caused interference when augmented with an antenna:

- In a Massachusetts town, youthful radio enthusiasts were found operating a "wireless broadcast" network built from kits.

- In Grand Rapids, Mich., four miniature transmitters were used by youths to broadcast phonograph records.

- At a western university, boys living in a dormitory operated phonograph oscillators as unlicensed transmitters to serenade the girls in a sorority house.

Advertisers of low-power "broadcast kits" have been requested to include with their sets warnings that the devices may be operated only in compliance with part 15 of the Commission's rules.

(page 122)
"An article which appeared in a national youth magazine about a low-powered broadcast station operated by youths in California was responsible for an increase in unlicensed broadcast operation by youngsters.

 In one instance a young man was conducting a "man on the street" interview program over his unlicensed broadcast station and one of the curious on-lookers was an FCC engineer who promptly terminated the operation.

A youth in New England interviewed on a weekend national network program was heard by an alert field engineer and his broadcast station was subsequently closed, only to have his irate father protest to his Senator.

Low Power Communication Devices
Local interference problems are aggravated by persons who operate low-power communication devices which exceed the radiation limits prescribed in part 15 of the Commission's rules. Unlicensed use of wireless microphones, phonograph oscillators, electronic "baby sitters," home intercommunication systems, remote control of model airplanes, etc., is permitted on certain frequencies but under strict limitations as to power, antenna length and radiation. But many of these operations exceed the limits and interfere with licensed radio services.
This is especially true of juveniles using mail order kits of home-assembled equipment to "broadcast" voice and records to a neighborhood. Besides taking action against violators, the Commission continues to seek the cooperation of manufacturers, sellers, and users of such devices to see that they ate certified as meeting technical requirements.

Carrier Current Broadcast Systems
There is continued interest on the part of colleges, churches, and individuals to establish carrier current broadcast systems or to increase the power of existing systems. However, to avoid interference to licensed broadcast stations, section 15.7 of the rules limits radiation so that associated receivers must either be connected directly to the distribution cable or in close proximity. Sampling investigations over the years have consistently indicated a tendency to exceed the allowable radiation limits.
 Operators have been warned of the consequences that could result from excessive radiation, but there is particular difficulty with colleges because of changing student bodies in charge of so-called "campus" broadcast systems. Lack of personnel has made it impossible to investigate the carrier current systems at all colleges. The Commission is studying proposals in docket 9288 for possible amendments to the existing regulations.

Type Acceptance of Transmitters
The Commission's type-acceptance program is designed to evaluate the technical adequacy of transmitters used in most of the radio services.
Type acceptance is based upon evaluation of descriptive and measurement data usually furnished by the manufacturer, or occasionally by the applicant for license. If such data show that the transmitter is capable of meeting the technical specifications of the rules governing the class of station for which the transmitter is designed, type acceptance is granted.

 If circumstances warrant, the Commission may require that type-accepted equipment be submitted to its laboratory for inspection and test to substantiate its capability of compliance with applicable rules.
The Commission's type-acceptance data and other information on equipment filed for application reference purposes are not open to the public but are useful to the Commission in determining the technical characteristics and capability of transmitters.
Applicants who have once filed such data can iudicate on subsequent applications that the infonnation is already "on file."

An interesting bit of trivia.. Licenced operation in the 900mHz frequency is secondary to unlicensed operation in that band. This is because part 15 in 900mHz came into existence before licenced operation ever did.

900mHz is the only exception in which Part 15 operation actually trump's a licensed operation.

The first certified part 15 AM transmitters came into existence in 1971 which were marketed by Info Systems Inc.There were three different models from 1971 to 1974, they were manufactured by International Telephone and Telegraph (ITT), Digital Thechnologies Inc (DTI), and Technical Systems Inc. {TSI). In 1974 the National Park Service quit buying from the Info-Systems company which caused them to go out of business.

So who was manufacturing part 15 whip and mast transmitters for the next 20 years before the LPB AM-2000 (aka TS-100 Trans-AM) transmitters came out around 1994?.. The use of part 15 whip and mast transmitters continued to increase quite substantially throughout the US by the NPS on through the 1970s-80s, but I could find no mention of where those transmitters came from.. but now I think know..

Around the same time that Info Systems went out of business (1974), a new company arose called Audio-Sine Inc. with their own part 15 whip and mast transmitters. Apparently they came out in 1974 to create "Talking Billboards", but the same transmitters were also utilized by government agencies,

Other than that, don't know much about them, Presumably these were certified units, (wish I could find a picture or something of one).. Anyone know anything about them?

Audio-Sine later became a primary supplier of ten-watt AM transmitters in 1978 shortly after TIS was established by the FCC in 1977, but I only found two specific examples of their part 15 transmitters being used (shown below), but I highly suspect it must also be what the NPS was using during those years. One would think these might turn up occasionally on eBay, but I've never seen one.

Anyway, here are two examples of the Audio-Sine Part 15 transmitters being used:


Star Tribune from Minneapolis, Minnesota · July 26, 1974 , Page 6
Staff Photo by John Croft
(Image shows girl on a bicycle looking up at billboard)
caption: Drivers of vehicles without radios can't hear the talking billboard at 66th and Nicollet.

Talking billboard makes debut on its own frequency
By Don Lewis Staff Writer

At last. A billboard that says something literally. It glares in bold black, white and yellow, boasting its novelty and soliciting listeners. The curious motorist who responds and turns on his car radio is introduced to a male voice accompanied by background music. "This is a talking billboard, the first of its kind in the Twin Cities," the sign declares. "Look for talking billboards throughout this area in the near future."
Described by its conceiver as "a new dimension in sound," the signboard-orator has made its Minneapolis debut performing since Tuesday atop the Hub Shopping Center, W. 66th St. and Nicollet Av.

The concept, according to Mort Garren, vice president of Audio-Sine, Inc., is as easy to understand as turning on your radio. Behind the poster rests a low-power one milliwatt AM radio transmitter and a tape player, which broadcasts a 40-second message. Any motorist within four to eight blocks of the sign can tune his radio to the frequency posted on the sign and hear the recorded message. "There is no equipment like this in the billboard industry," said Garren, who explained that his idea might lead to creative, custom-designed billboard advertising that a driver can receive without taking his eyes off the road.

The sign was activated this week by Audio-Sine, a Minneapolis electronic communications firm, and Naegele Outdoor Advertising Co., of Richfield. "It's a beautiful application" of mobile sound equipment, according to Garren, who hopes the idea will catch on, particularly with public service advertisers.

Naegele president Bob Naegele jr. called the sign a "novelty item" in the experimental stage. Though it is too early to evaluate the idea and its chance of success, Naegele admitted it might have some potential. "Give the advertiser a strong visual and a strong audio, and you get a double," he said.

One obvious drawback, Naegele explained, is that the advertising audience is limited to motorists who own car radios and who then make the effort to tune in. In any case, "it's a lot of fun just driving by," Naegele said. Garren agreed. "We're going to let the board sell itself. And I think it will."


Analysis and Design Guidelines for Highway Advisory Radio: ...
...The other HAR transmitter located on top of the Houston Airport Hotel operates at low power at a frequency of 1100 kHz. It operates under Part 15 of the FCC Rules and Regulations. It, too, consists of an Audio-Sine transmitter and power supply and has a Morad vertical monopole antenna system. Its location ideally covers the main airport parking lots. This frequency was selected for its mid-range on a car AM radio dial. The audio for both systems is supplied via leased telephone lines..



Operational Site Survey and Broadcast Equipment Guide
Report Date April 1979

Houston Airport HAR
In April 1978, the Houston Intercontinental Airport (HIA) was granted an FCC
 TIS allocation to operate a 1610 kHz AM station. Prior to this, the airport utilized an 1100 kHz AM station under FCC part 15. Currently, both of these stations are used to inform motorists of airport parking lot status and provide live "on-the- air" broadcasts in an undue emergency...

The 1610 kHz TIS station consists of a 10-watt AM transmitter and a MORAD
 vertical monopole antenna. The transmitter and the antenna are installed on the air conditioning shroud of an FAA office building on Kennedy Boulevard .

The 1100-kHz AM station consists of a 100-milliwatt transmitter impedance
 matched to a citizens band whip antenna. The 1100-kHz station hardware is
 installed atop a hotel at HIA.

Both AM transmitters are modulated simultane
ously from an 8-track tape recorder situated in the HIA Terminal A operations room. To interconnect the 8-track tape recorder to each transmitter, zero loss leased telephone lines are utilized. Both systems are currently maintained by a local communications firm,.. ..Since HIA was the first operating agency to obtain a TIS authorization, HIA has generated considerable interest in HAR by the airport operations community ....

Part 15 AM and FM Station Operation / Part 15 EAS kinda
« on: October 05, 2020, 1409 UTC »
I first noticed this when it was featured as a new product in the June issue of The Source newsletter (which also features a few part 15 use stories), and I keep going back to it because it's such an interesting product. Its called a Severe Storm Detector, boast a 95% accuracy rate and it cost about a hundred bucks.


Its small, operates on AC or 9v battery, requires no wifi, does not rely on the NOAA or other service. Instead it actually monitors the areas atmospheric conditions via radio waves within a 30 mile radius of your own location and instantly alerts you of severe Storm conditions, often times several minutes before it even gets reported by the NOAA on a weather radio.

It specifically indicates: tornado, tornado risk, severe storm, storm (not severe), lightning, and no threat. It also tells you in real time how close it is. The only thing I don't like about it is that it doesn't make vocal alerts, instead it uses a siren and a flashing light along with a small display.

However, I suppose you could couple it with a silence detector (Angry Audio has a real nice one) and have it automatically interrupt your broadcast with that siren sound..

Anyway, it'd just an idea, a real time, uassisted severe storm alert of some kind would be a great addition for any part 15 station, but utilizing an standard weather alert radio is probably a better option, but still I think this unit is really cool, I just wished it talked.



In a previous thread about the FCC refusal to grant higher part 15 FM limits for churches during the covid epodemic... I mentioned that perhaps the churches should look into how the new Walmart Drive-in movie parking lots are doing it - and the answer is..evidently, they are using the FCC Certified  part 15 AXS-FMTD fm transmitter manufactured by BMV (Broadcast Vision Entertainment)
It cost $299 and boast a range of 'up to 300 feet in all directions.


It seems that 300 foot would be sufficient for most church parking lots, but I suspect those churches are really desiring to reach the surrounding area of homes... But anyway Pia had suggested that if churchs wanted to extend their fm range then simply use more transmitters... With that in mind, a single transmitter could not likely cover one of the Walmart Supercenter parking lots to supply audio of the film's, so, presumably multiple transmitters are being employed for each location..

But wouldn't multiple FM transmitters on the same frequency interfere with each other the same as it does on AM??? Maybe different sections of the parking lot provide different frequencies.. I don't know, but here's what little I do know about the Walmart Drive-in operation:

In 2003 Robert De Niro, Jane Rosenthal and Craig Hatkoff, founded the Tribeca Film Festival, Tribeca Film Festival International, Tribeca Cinemas and Tribeca Film distribution, all of which partake with numerous partnerships with other companies and organizations.. in this case Walmart to provide free outdoor movies in their parking lots -- and what Tribecca uses for its film festivals is the formentioned certified Part 15 ASX-FMTD.

Personally, I still think using AM would be the better option for both Wa!mart and the churches. I wonder why they continue to focus on the FM option.

Part 15 AM and FM Station Operation / FCC vs God
« on: September 18, 2020, 1243 UTC »
Congressman Mark Green request the FCC to allow churches to exceed part 15 limits, Pai says no, just use more transmitters instead.


General Radio Discussion / hfundergrounds wiki pirate list error
« on: February 23, 2019, 0122 UTC »
Hi, I've never been here before, I generally hang out on part 15 hobby forums, but I happened across your wiki page listing pirate stations and noticed "Radio Sausalito" was included in the list, but they are not a pirate station! They legally operate under part 15 and have been doing so for 20 years! It kind of irked me when I saw that.

I'm interested to hear your comments concerning this.

Also, I haven't examined the list closely but am curious how many part 15 stations you might have listed there. Do you not distinguish between legal unlicensed operators and pirates?

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