Messages

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Part 15 AM and FM Station Operation / Re: Hardware vs Software Processing (revived)

« on: September 10, 2025, 2100 UTC »

Well I've now pretty much made the decision to get the SW205 as soon as they're released, had few brief correspondence with Jim Wood in the last few days. As much as I loved my old Aphex pair, they had been manufactured, what, 40 years ago? and I have no experience in servicing electronics if it needs it, so it flat out makes the most sense to buy a brand new Schlockwood that's designed by a reputable (and legendary) manufactured specifically for the purpose - and the price is right.

The more I think about it, not doing so would be just wrong! I look forward to getting a Schlockwood! Maybe I'll find I like it even more than my beloved lost Compellor/Dominator.

Schlockwood it'll be.

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Part 15 AM and FM Station Operation / Re: Armed Forces Radio Network on base via Part 15 ops? Apparently....

« on: September 08, 2025, 2135 UTC »

My Uncle, who served in the US Air force for 20-some years, told me this little tidbit about a Part 15 AM operation:
"In 1979 when I was at Eielson AFB, Alaska they had an on base carrier current radio station.  Run by Armed Forces Radio.  .... ..

Apparently "Mike from Delaware" over at RadioDiscussions worked at that same station during 1972-1973. Somewhere else I saw that it had broadcast on 1490:

https://radiodiscussions.com/threads/afrts-to-drop-talk-radio-broadcasts.473659/

MikefromDelaware
Jun 20, 2006
#6
I worked on AFRTS while in Alaska during the Viet Nam War (1490 AFRN Eielson AFB, Alaska). The movie "Good Morning Viet Nam" is realistic as the other poster mentioned. Sounds like some things have changed as we had only one station which meant "block programming". One hour top 40, then Classical (as in Beethoven and Mozart), then Soul, then Country, then Big Band, etc. Sports were important, at least on AFRN (Alaskan Forces Radio Network) as back then (1972-73) .... .. ... So radio was important for sports as we'd get the network radio feeds from ABC, CBS, NBC, and Mutual live via phone lines so we aired the World Series and the Super Bowl live plus many of their features like Paul Harvey, some CBS and NBC commentaries, plus we'd air hourly news using all of the networks at different times of the day. We'd carry all sorts of sports, which seemed to be very popular with the younger military listeners as well as near by civilians who lived near the base. Of course today, AFRTS may have all the games available live on TV so the demand to listen to the games on the radio may be very small in today's military.

Back then, AFRTS had its own record label. You weren't allowed to use civilian records. Of course, this gave them (the programmers at AFRTS network headquarters in LA) complete control over what songs were available or could be edited if lyrics were offensive (for those who weren't around then, the Viet Nam War was not very popular with many folks so there were a number of anti war songs, etc put out back then). The odd thing though, was we also aired Kasey Kasem's American Top 40, so even though we couldn't play a certain song, Kasey could and did. It was fun to hear what songs we didn't get or if they had edited the version somehow. I wonder if AFRTS still has it's own label today? Of course, if AFRTS drops all local programming and simply goes with satellite syndicated music shows from the civilian world then censorship wouldn't be an issue as they'd not have any control over content of a show say from ABC radio or Westwood One, etc.

....Every now and then, if on an "off shift" when no one else was there, it was known to happen that civilian records were sometimes brought in and played.




Another:

MikefromDelaware
Jul 17, 2007
#2
I was stationed at Eielson AFB, about 30 miles east of Fairbanks back in 1972-73. Back then they didn't have satellites for TV there so the network shows were mailed up and aired about a month later. Yes the Christmas shows aired there in January. The exceptions to this was the news which was flown up from the lower 48 so that Walter Cronkite read you yesterday's news. Also major sporting events like the World Series and the Super Bowl were flown up the next day, making radio a big player then as radio network programming came live over phone lines, which meant you could listen to the Super Bowl on the radio live and then watch it the next day on TV

3

Part 15 AM and FM Station Operation / Re: Armed Forces Radio Network on base via Part 15 ops? Apparently....

« on: September 08, 2025, 1958 UTC »

I don't recall actually ever listened to any part 15 military stations that I recall, but they have certainly existed for decades (ever since the 1940s) at numerous bases, most commonly carrier-current AM.  Military documentations as late as the 1990s (perhaps even later) actually specifically address the operation of part 15 AM on bases.

But no, I've never actually listened to one.. not knowingly anyway.

Google AI provides a good overview of the first military part 15 AM network, which were at numerous locacations around the world at the time. I was known as "The Star Spangled Network:

The Star-Spangled Network was a USO radio network established in 1941 that predated the Armed Forces Radio Service (AFRS) by several months to broadcast entertainment and morale-boosting content to military personnel. It used wired radio systems, where studios in USO clubs broadcast directly to radios on nearby military bases, bypassing traditional radio frequencies. This network was part of early efforts to support American troops during World War II and was a precursor to the later, more comprehensive, Armed Forces Radio Service (AFRS).

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Part 15 AM and FM Station Operation / Re: Hardware vs Software Processing (revived)

« on: September 08, 2025, 1945 UTC »

You say you "like computer aided, not computer dependent". Amen to that. I doubt there are many part 15 stations that operate without a computer, but suspect only for music automation and prep. The general preference always appears to have been hardware processing, and that's all I've used in the past.

But on the flip side, software processing can be a lot cheaper or even free. But that also further taxes your computer which as you point out can lead to problems. Yes, I agree, hardware is the way to go

However, are not most of not all hardware processors today simply all-in-one dedicated software computers anyway? - Yeah I know it's different because it's dedicated, but still, just saying.

Curious if Boomer pre-processes everything with software prior to air, or actually processes in real time during air? Pre-processing it seems wouldn't be a problem... unless of course the programing is actually live.

Well bottom line, I agree. Right now I'm debating between what I'm already familiar with (a used Compellor/Dominator pair), or a brand new Schlockwood SW210.
- Either way you're looking at about $300, but there's always a risk with used equipment, so I'll most likely go with one of the new budget Schlockwoods as soon as they come out. It just seems the most prudent.

But then again, I could pre-proccess everything with free software and save $300. --- But I think that would get old real quick.

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Part 15 AM and FM Station Operation / Hardware vs Software Processing (revived)

« on: September 08, 2025, 0722 UTC »

A real interesting thread from back when the Schlockwood SW200 first came out that talks about it, as well as pro's and cons of using a PC with StereoTool or  plugins to accomplish the same thing. It's a hardware vs software processing debate.

https://www.hfunderground.com/board/index.php?topic=49947.0

 Most interesting I think is where a guy named Kage announced he was scratch building his own processor "loosely designed after the Dorrough DAP 310 from 1973", and then later came back and revived the thread with the completed schematics and video demonstration.

Something that jumped out at me is where chantino said:

Best bang for your buck using hardware, if in fact you want it to sound loud and clean, is the Aphex Compellor/Dominator combo. ... ... .. This is not going to give you a heavily. noticeably processed sound, but it will be quite, again, LOUD, but still pleasing compared to the typical flatlined mid/highs and overbearing bass commercial station...

I used that pair for years with my station  and loved them, wish I still had them. I had sought them out because it was specifically advised in an article on the Rangemaster site about processing (It wasn't written by Hamilton, and he doesn't remember who wrote it). So I found one, then the other on eBay, and was immediately impressed, they made a noticeable difference, definitely better than the 421 and an equalizer I had previously used. -- But anyway, later there were numerous times that Bill over at HB had advised me to get rid of the Dominator and replace it with something else, because the Dominator was not designed for AM. I kind of figured he knew what he was talking about, but I just couldn't bring myself to change something which seemed to be performing so well.. I don't mean range really, I really don't know if it improved range or not l, but the sound quality was great, full. I really liked the Aphex Compellor/Dominator pair and am considering trying to find another set, even thought the Dominator was evidently actually designed for FM. But I'm also still considering the Schlockwood.

Incidentally, in case you haven't heard, the original Schlockwood SW200 has now been discontinued. It is being replaced within the next few months by two different models; one is a $500 professional rack mount version with more bells and whistles, but the other model, the SW210, which apparently is a SW200 with just a faceplate but no encloser,  it's  only going to cost about $300, and that sounds like a very inviting price to me.
https://www.schlockwood.com

But I haven't totally abandoned the idea of just using free plugins either. So I'm curious.. actually I think I know the answer already ..

How many part 15 AM stations use only software based processing?

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Part 15 AM and FM Station Operation / Re: Emcore 2804TK-SCAP/12 CATV VSB/AM Transmitter 1310 nm.

« on: September 07, 2025, 2008 UTC »

Ok, that makes sense (I had no idea what the "nm" signified), but it's called a "VSB/AM", which Google tells me:

"VSB/AM" stands for Vestigial Sideband Amplitude Modulation, a technique that transmits one full sideband along with a small portion ("vestige") of the other sideband to save bandwidth while simplifying demodulation compared to single-sideband (SSB) modulation, and is notably used in digital TV broadcasting like the ATSC standard.

Yeah, well, that's over my head, and why I posed the question here. Since the unit is designed to pass an amplitude modulated signal, does that mean it could be easily modified to utilize as an AM carrier-current system?

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Part 15 AM and FM Station Operation / Emcore 2804TK-SCAP/12 CATV VSB/AM Transmitter 1310 nm.

« on: September 07, 2025, 0423 UTC »

I saw this rack mount unit on eBay and am curious if it could be utilizes as only an AM carrier-current transmitter? I don't know anything about this thing, but could it be the "1310 nm" refers to the frequency for audio?
I personally have no need for such, but if turns out it could be used as such then I'm sure someone would be interested. It's $99 or best offer. There's numerous  pictures in the auction. To be clear, I'm not the seller, just saw it on ebay

Emcore 2804TK-SCAP/12 CATV VSB/AM Transmitter 1310 nm
https://www.ebay.com/itm/156451980138


Item description from the seller
This sale is for a Emcore 2804TK-SCAP/12 CATV VSB/AM Transmitter 1310 nm. Item powers up and it's in good cosmetic condition. We are unable to test it for “full” functionality ourselves at our facility. There are some scratches and/or scuff marks on the item from normal use. It will also come with a power cord.

Item comes with a full 30-day warranty (US Only).

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Part 15 AM and FM Station Operation / Re: Great Part 15 AM Station, TX & Antenna System, from ARF! Plus explaination!!!

« on: September 03, 2025, 1501 UTC »

Now that I've read the rest of it I realize he appears to fully comprehend 15.219 but for whatever the reason his objective was for his designed and constructed "Pantry Transmitter" to simply conform more to 15.209. I guess because from outside the USA.

The PDF is very interesting but I still feel like I'm missing something. I know I'll be taking a second look at it. It stands out as  significant to me, but a little perplexing at the same time. But its it's definitely worth reading.

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Part 15 AM and FM Station Operation / Re: Great Part 15 AM Station, TX & Antenna System, from ARF! Plus explaination!!!

« on: September 01, 2025, 0648 UTC »

I've read the first three pages and only skimmed the rest so far, but those first three pages where captivating!
I don't know who Dr. H. Holden is but like his writing style, and I never knew the term "Pantry Transmitter" is what they call a part 15 transmitter in the UK! That's a cool bit of trivia. However, he said something else that I found peculiar - in that it's flat out incorrect, - or maybe I just missed a context somehow, but here's the quote from page 2:
"•••••
"Although these regulations don’t apply in all countries, the USA’s FCC’s Part 15.219 Regulation Transmitter Specifications do provide a useful “metric” to avoid interference to others.
Obviously any MW band AM transmitter circuits, regardless of their RF amplifier design, combined with some design of Antenna structure, must never be allowed to transmit a higher actual electromagnetic (EM) wave power than the “FCC’s regulation transmitter-antenna arrangement”
"••••••
Am I misunderstanding what he's saying? To me it sounds like he saying that regardless of the circuitry or an alternate antenna configuration that it obviously must still adhere to a certain field strength - "EM wave power" - Is that what he's saying? Or am I misinterpreting?

I mean several FCC documentations clearly state 15.219 has no field strength limits associated with it. I mean that's almost the exact words (I can pull something up in short order if need be). The are no field strength limits associated with 15.219

Or am I making a fool of myself and that's not what he's saying at all? I read the above quote 3 times, maybe I'm just experiencing a brain fart or something.

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Part 15 AM and FM Station Operation / Skinners Tunnel Radio

« on: August 07, 2025, 0343 UTC »

I never heard of this book or know who Rollye James is:
What Am I Doing Here? (when everything I want is somewhere else)
a Radio Repair Manual - for what's not working in your life
https://www.worldradiohistory.com/BOOKSHELF-ARH/Biography/What-Am-I-Doing-Here-James.pdf

I got drew in around the middle of:
Chapter 15
The Value of Creativity – Part One
Winning the Battle

Beginning on page 203, it's telling the story about beginnings of CKLW Detroit-Windsor Tunnel radio (though with incorrect dates) and then follows that with chronicles of Rodger Skinner and his similar low-power ventures with his Tunnel Radio franchise - and then that's followed by the story of station WNOP in Newport,
Kentucky that floated on the water...

I'm not really sure what this book is about, but as far as part 15 goes pages 203-207 are pretty interesting.

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Part 15 AM and FM Station Operation / Re: A free AM Carrier-Current Coupler Unit? You might already just have one. PIC

« on: July 11, 2025, 2132 UTC »

https://www.edn.com/teardown-inside-a-dsl-gateway/  Ya know, ya look for tear-downs of DSL MODEM's, and everyone that has done so, and taken PIC's & VID's, are more interested in the IC's. However, what we are interested in, for our Carrier-Current purposes, is the built-in coupling unit. That link is more promising. From the green RJ-11 connector, follow that to the square block marked MOC. That, appears to be the coupler. Now, if we can get the pin-out INFO on that, this maybe our freebie coupler, as well as those coupling mylar CAP's that I see in there. Hmmmmmmmmmmmm... Me thinks me getting warmer?

To be honest I'm pretty confused about what the guy in the article accomplished, or if he accomplished anything. At the same time I'm also confused over your exploration of how the DSL modem parts can be utilized for AM carrier current coupler.

I dont know much of anything about cobbling together electronic components from scratch or from repurposed parts, but I wonder why a carrier current coupler should be so complicated to make when the greatest majority of the carrier current stations over the last 80+ years had been assembled and put in operation by young inexperienced college students.

Is there really something so complicated about a coupler that the average Joe is unable to construct one himself?

I feel like I'm missing something here. I mean, how complicated can this box be? (LPBs TC2 coupler):


blogs.telosalliance.com/lab-carrier-current-am-transmitter

"The T2C matched the 50-ohm output of the transmitter to the (usually) much lower impedance of the power line, and also isolated the RF output from the AC line. .... The output of the T2C was usually connected to all phases of a building's AC service through a 4-prong plug and mating socket connected to the main breaker panel. 3-amp fast blow fuses provided the last line of defense."[/i]

If I'm missing your point, then I should be excused because I'm quite confused.

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Part 15 AM and FM Station Operation / Re: A free AM Carrier-Current Coupler Unit? You might already just have one.

« on: July 09, 2025, 2110 UTC »

Ever look at this? Says no coupler is needed. Excerpts below

https://k6prk.k6fb.com/CARRIER%20CURRENT%20AM%20TRANSMITTER.HTM

This transmitter makes use of the "neutral feed" system which may extend range over the typical "hot feed" method in certain situations and in any case will reduce or even eliminate the hum which typically plagues carrier current systems using the latter means of coupling to the powerlines. No coupler is needed with this unit; since the injection of RF into the neutral wire is internal, the unit simply need be plugged into an ordinary outlet. ... .. ... This transmitter's final tank values as shown above were designed for the middle of the AM broadcast band (~800-1200 kHz) but can be changed to any desired portion of the band, by simply increasing the number of turns on L1 ....

  .... When moving the unit from one outlet or branch circuit to another, retuning of L1 may be necessary. Also, if
 still is not satisfactory, it may be that your power system neutrals are not continuous throughout the entire grid or area.... ....

If it is desired to make this transmitter a "hot feed" unit instead of a neutral feed, simply unground the cold (grounded) end of L2 and feed via a .01 uF, 2 kV ceramic disc capacitor to the hot 117 v wire in the transmitter between the fuse and RFC3. No other changes need be made. These coupling capacitor values are not "etched in stone" and may be changed to tune out reactance in the lines if found to be necessary (in fact experimentation here is encouraged). ..

At the same link is a ....


A Universal Line Coupler For Carrier Current Use (Both "Hot" and "Neutral" Feed Methods)

Because of the great demand for a coupler design which will serve all methods of feeding AM broadcast energy into AC power circuits, a configuration is presented here which is felt to be about as "universal" as one can get. This ......

But I guess that's getting away from the topic of a free coupler by repurposing existing devices.

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Part 15 AM and FM Station Operation / Re: Tunnel Radio: How Signals Reach Drivers Underground? RW rip...

« on: June 14, 2025, 0325 UTC »

This is a really cool find! (imo)

Ths video is a year old but in it they talk about a 10 mile long tunnel radio system project in the late 1990s that involved 117 different frequencies for underground communications. Nothing like this had been attempted before, big companies like Honeywell and Nada(?) tried, but the ones that came up with a working solution was these two guys of CanAm Technologies a Canadian company; "leading specialists in communication systems for tunnels and other enclosed environments". The two are interviewed by the host here.

Now two of those frequencies involved the broadcast band, and that's where the part 15 AM and FM comes in.

In the late 90s they took on a project for the ten mile long tunnel undet the city of Boston on Intetstate 90 I think. Part of the objective included communication for the drivers. So they set it up the entire 10 mile stretch of tunnel for drivers going Eastbound would tune into the AM broadcast, while those going West tuned to FM (or visa versa), so the information provided would correspond. He also goes into some detail about the leaky cable design and so forth.

It's a long video, I guess the most interesting is between about the 12 minute mark until about 30 min. But I'm going to have to watch it again cause I feel like I may have missed something.

https://youtu.be/WCm0mTjP0Bo?si=coFmuPA8H4IxX4hy

In this riveting seventh episode of Das Talk Podcast, host Peter sits down with Victor Bermudez and Michael Martinez from CanAm Technologies, leading specialists in communication systems for tunnels and other enclosed environments. The conversation delves deep into the nuances and challenges of creating robust communication infrastructures where conventional methods fall short.

Key Takeaways:
Innovative Use of AM and FM Signals: CanAm Technologies leverages both AM and FM radio signals uniquely to ensure that emergency communications reach drivers within tunnels...."

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

« on: June 11, 2025, 2122 UTC »

Just bought a Rangemaster 1690 crystal combined with a Ragemagster audio interface for $18 in Ebay

I grabbed it just to have on hand, but like I said I'm really looking for something below 1600..

PS. Surprisingly those little audio interfaces  for the Rabgemaster are $99 at Progressive Concepts.. What makes them so expensive? that really surprised me.

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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?