Topics

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Part 15 AM and FM Station Operation / Rangemaster Crystal's & Lower Frequencies

« on: June 09, 2025, 2023 UTC »

Someone told me (I think it had been Dave) what to look for when seeking crystal's for the older model Rangemasters but now I can't find it again and for some reason not on Rangemaster site either. so I'm not sure what's right..

Anyway I've had thoughts about trying some lower frequencies as an experiment .There at least once existing part15 AM that's been on 1400 for years in Montana, so I'd like to try it for the sake of old radios.

I've seen some AM Crystal's that require a FT-243 socket and also have come across some HC-6/U Crystal's with these frequencies.. what's with the peculiar AM frequencies?

1000
1311.4
1306
1363.6
1400
1572

But my main question is what kind of crystal's is right for the original Rangemasters?

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Part 15 AM and FM Station Operation / Part15AM on 1700 in 1940s?

« on: June 05, 2025, 0318 UTC »

It kind of surprised me to see this 1947 Adaptol Phono Oscillator on ebay that has a broadcast range from 1100-1700.
https://www.ebay.com/itm/197193149980


At first I thought that was odd, since the expanded band didnt come into existence until the 1980s(??), but 1940s advertisements confirm it - then I got to wondering if maybe they simply splattered across the entire AMband (for about 70 feet) and you just tuned to whichever.. like tunnel radio did.

I know there were phono-occilator designed for specific AM bands, but apparently (seemly anyway) also those that covered the entire band?.. I mean surely this thing wasn't tunable, was it?

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Part 15 AM and FM Station Operation / City Dump Growth Blocks Radio Waves

« on: April 24, 2025, 1456 UTC »

This isn't about broadcast radio, its actually reffering to the microwave communication system towers used by the county and city public safety departments, but still I never heard a story like this one..
The city dump is getting so high that officials are having difficulty  communicationing by radio..  It just occurred to me that the top of that landfill would be an ideal place to put a 100% compliant part 15 AM 3 meter whip and ground lead (if used) install.

Landfill growing so high it could block radio waves; City, County OK fix
https://www.wane.com/top-stories/landfill-growing-so-high-it-could-block-radio-waves-city-county-ok-fix/amp/

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Part 15 AM and FM Station Operation / When did Part 15 FM not exist?

« on: March 30, 2025, 1622 UTC »

TheDood's post about cable FM brought this related topic back mind that I fond confusing...

We go back to Bulletin OCE 12 (March 1973) :
https://docs.fcc.gov/public/attachments/DOC-335623A1.pdf

13.0
OPERATION PROHIBITED IN FM BAND.

Due to the physical laws of radio propagation on frequencies in the AM band, operation with low power and a small antenna is inherently short range. Thus, it is possible to set up operating conditions in the AM band that will protect the broadcast service and still provide a reasonable operating range for the owner of a low power communication device.

This cannot be done in the FM band (88-108 MHz). Conditions in this band are completely different and long range transmission is possible even with extremely low power, a fact that is well known and well documented. In the face of this physical phenomenon, the Commission has not found it possible to set up operating conditions on the FM band that would provide a reasonable operating range.

Accordingly, operation without an individual license for low power broadcasting in the FM band is strictly prohibited...."

But here's the thing.. Part 15 FM, so far as I can tell has ALWAYS been permitted! There's no other FCC documentation to indicate otherwise neither before nor after 1973 that says part 15 FM was ever strictly prohibitted, in fact there had been numerous part 15 FM devices on the market, for example this ad in 1966 Popular Mechanics magazine:

So how do we explain the FCCs 1973 Bulletin OCE 12?

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Part 15 AM and FM Station Operation / Merry Christmas! ( and Zeno)

« on: December 25, 2024, 1058 UTC »

Been messing with the free version of Zeno (zeno.fm). They have something called Auto DJ that takes over if your stream fails or if your just offline.
You upload upload to 200 songs and it plays it when your stream is off.

I don't even have a stream, but I uploaded a few dozen original Christmas tunes, wide variety in the genre, but all Christmas.
Some of these are really good. Other meh..
So..
https://zeno.fm/player/end80radio

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Part 15 AM and FM Station Operation / Free to air songs

« on: November 06, 2024, 0604 UTC »

I've been passing these around. I think their great, it about part 15 AM broadcasting. Only problem is that their in stereo. (Sounds ok on one channel, haven't tried downsampling yet)

Female version, catchy upbeat. 3:30:
https://aimusic.so/music/3720298-Can-you-hear-me-over-there-

Male version, heavier, like Nirvana, excellent 5:34:
https://aimusic.so/music/3731647-Can-you-hear-me-over-there-

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Part 15 AM and FM Station Operation / Is a TH essentially also CC?

« on: November 03, 2024, 1908 UTC »

With Talking Houses and similar transmitters which acheive ground via the power outlet..

Doesn't that essentially cause it to also act as a carrier-current station? Wouldn't any receiver near a power outlet receive the signals even if the free-radiating signal was obstructed by walls and floors or whatever?

I realize it's not near the power of a carrier-current transmitter, but wouldn't the signal still travel a long way through the wiring?

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Part 15 AM and FM Station Operation / "Part 15 AM Radio Broadcasting Systems"

« on: October 17, 2024, 1925 UTC »

Today's random clip comes from the
1999 FCC Compilation of Decisions, Reports, Public Notices, and Other of the FCC Volume 4, Part 4 (link below)
 
The history itself is interesting, this was 25 years ago, campus stations were still prevalent, the AM band was expanding, part 15 rules were changing, but something that stood out to me was how the FCC defined these stations as "Part 15 AM Radio Broadcasting Systems", also the arguments for more range and the FCCs response, as well the compromises acheived.



https://books.google.com/books?id=p6tbZWD-98EC&pg=PA3516&dq=%22part+15+am%22

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Part 15 AM and FM Station Operation / LF/MF Short Vertical Antenna calculator

« on: October 17, 2024, 1654 UTC »

Came across this calculator, you have to enter four variables: https://people.physics.anu.edu.au/~dxt103/calculators/Rrad.php

1. Enter.antenna height in metres: 3
2. Enter frequency in MHz: 1650
3. Enter transmitter power output in watts: .01.

But I get stumped when it ask me to
Enter antenna impedance (dominated by ground loss plus inductor loss) in ohms:
It defaults to 40, but what should I be entering there?

https://people.physics.anu.edu.au/~dxt103/calculators/Rrad.php

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Part 15 AM and FM Station Operation / Do part 15 signals kill insects?

« on: October 12, 2024, 2320 UTC »

This is off topic of part 15, and, sorry to say I'm not even sure where this clipping  came from, except to say it was proubally a 1930s magazine like Popular Science, or Radio News or something. I took a screenshot of it one day

https://drive.google.com/file/d/1XasE5e00j2biJ7rsuLbwhgQmQVzpsIwY/view?usp=drivesdk

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Part 15 AM and FM Station Operation / AI does Part 15 broadcasting.

« on: September 23, 2024, 0359 UTC »

On impulse I just spent 30 seconds with an AI song generstor.. it provided two versions, I liked them both, but this one I liked a tad better.. mp3 dwnload:

https://www.dropbox.com/scl/fi/nlttxjk2bbq83h59xj32v/AI-Music-2.mp3?rlkey=jgjh40q89crzhkc7sz8yc4dna&st=bhzifjk4&dl=0

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Part 15 AM and FM Station Operation / AM Radio Knows What's Dead

« on: July 25, 2024, 0132 UTC »

Here's a useless story, just for the fun of it:

AM radio waves, spirit boxes and thermal cameras set up to contact ghosts at John Tomay Memorial Library 
July 18, 2024
https://coloradocommunitymedia.com/2024/07/18/am-radio-waves-spirit-boxes-and-thermal-cameras-set-up-to-contact-ghosts-at-john-tomay-memorial-library/

....The professional paranormal group set up in the basement of the Georgetown library and secured... a “spirit box” (an AM radio set to scan). “We might get voices through the spirit boxes, ...The stuff we’ll set up works off of energy and they are machinery that spirits can manipulate, ...energy stays here and knows that it’s safe and communicates with us. That’s what we’re trying to accomplish,” Hendrickson said...

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Part 15 AM and FM Station Operation / Where did the "Low Power Radio Guy" go?

« on: July 22, 2024, 2326 UTC »

About a year ago the long-running Low Power Radio Blog disappeared. I have no idea who he was but for the last decade I'd been visited his blog a couple times a month.. Until one day it just disappeared.
Here's a link to the archive:
https://web.archive.org/web/20220528044316/https://lowpowerradio.blogspot.com/

So, who is he, and why would he take his blog down? This is a mystery that occasionally nags me. I really liked his blog.

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Part 15 AM and FM Station Operation / First Part 15 AM College Station

« on: July 12, 2024, 0201 UTC »

You might think it was Brown University, but no, carrier-current was not initially a part 15 operation..
Thus, the first part15AM was actually  Dartmouth College... It's a debatable fact. But anyway there's a whole other story behind this, which I elaborate another time.

This article is from TIME magazine April 9 1940

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Part 15 AM and FM Station Operation / F.C.Was Canada first?

« on: July 06, 2024, 0120 UTC »

Often, while researching history of part 15 am, I ponder on how the FCC and the CRTC work together..

I know nothing about the history of Canadas equivalent to part 15AM (RSS-210), but am begining to wonder more about it after noticing some old magazine and newspaper mentions in  the late 1930s, just before Part 15 was created For example, in Radio & TV News - July 1938 page 69 (excerpts)

"THE FCC has taken a decided step toward helping the elimination of interference.. ..The Commission will be glad to furnish an opinion as to the type of filter which may be used for the practical elimination of interference potentialities. "This closely follows the Canadian Commission's system of eliminating interference from broadcasts. The Canadian Commission, however, maintains a group of troubleshooters, who go out and locate the interference and remedy it.
Interference with radio programs in Canada is a serious occurrence, and it is to their credit that the programs in Canada are freer from this annoyance than those of the United States. * *

And this one from August 1938 Radio News:

"...Yielding to the pressure of the millions who enjoy their broadcast radio reception, the F.C.C., on May 28, 1938, submitted a bill to Congress which stated, "no person shall operate or cause to be operated any apparatus which uses r.f. electrical current as an essential to its operation ... in any manner inconsistent with the rules, regulations, restriction or conditions which the Commission may prescribe under ... this section." The Commission, in recommending that Congress pass this bill, predicted that "the use of a large part of the radio spectrum for communications purposes will be destroyed," unless some laws and measures can be passed for the suppression of electronic interference. ...In presenting this act to Congress, the F.C.C. follows the lead taken by the Canadian Communications Commission prohibiting radio interference of any kind...."

Other articles like these about Canada leading the way into establishing interference laws is kind of intriguing.