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For the Love of Radio

One of the guys I work with is a little bit crazy. Well… actually more than one, but this one person in particular has gone out of his way to fix up a summer camp radio station.  So, the background is this; in a remote region, far, far away from thing else, a summer camp had installed a license free (allegedly FCC Part 15) radio station to cover the camp compound.   Many summers later, said camp management had some questions and concerns about the operation.  This is where our protagonist comes into the story.

Not only did the camp owners have questions about their operation, they also had coverage issues.  Their installation consisted of a Ramsey five watt all in one FM transmitter feeding a horizontally polarized television antenna on the roof of the studio fed with RG-6 coax.  There were several coverage holes within the immediate camp complex and they were asking of a more powerful transmitter was needed.  In light of this, our man Pete did some engineering outreach.  Over the period of several months, Pete scraped together what would have been mostly back shelf backup gear, perhaps a few things destined for the dumpster and other miscellaneous items and built a small radio station for them.

Camp Radio Station equipment rack

Camp Radio Station equipment rack

What was once, no doubt, an illegal operation was brought substantially into compliance by replacing the Ramsey broadcast transmitter with a QEI 675 exciter modified by removing the power amp and connecting the IPA to the output filter.  Thus modified, it runs a maximum of 0.2 watts, which is not necessarily the output power. The antenna was changed to a home made vertically mounted dipole antenna.  The addition of a broadcast quality limiter ensures that the station is not over modulating.  A recently calibrated Belar FM modulation monitor confirms this.  Some Texar Audio Prisms juice up the sound a little bit.  A Urei console, a couple of Shure SM-58 microphones and a computer round out the operation.

Camp Radio Station console and computer

Camp Radio Station console and computer

Now, the camp radio station has the feel of a real radio station.  Kids that come here to do shows get a fairly authentic feel and appreciation for what it is like to be a DJ; selecting music, doing intros, information, weather, etc.  By looking at the sign up board, it seems that radio can still be very popular with teenagers:

Camp radio station sign up board

Camp radio station sign up board, very few openings

Thus the camp owner has perhaps saved himself some grief with the FCC.  A potential interference and intermodulation situation has been avoided.  The new equipment covers the entire camp compound and better still, does not go too far beyond the front gate, which is exactly 121.4 feet away from the antenna mast.  Best yet, a whole bunch of teenagers are interested in doing radio shows and learning about music.  There are very few venues or paths for potential new talent to enter this business and things like this should be encouraged.

Update: A few sentences were changed for clarity.

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22 comments to For the Love of Radio

  • Paul, this is certainly an uplifting story about how radio can provide some benefit to young people. It was a similar situation that led me to build a campus-limited AM and FM radio station for a school district, which led me to create the website. Sadly, the school administration never appreciated what it could be and due to staff and administration mismanagement it withered away. That’s great that both the camp has a commitment to providing this for their visitors as well as a tip of the hat to your engineering colleague Pete for helping them out.

  • Rob

    What a great project, and what a fantastic equipment rack/chain! To see such a level of enthusiasm from the campers in return really ices the cake! Mad props to Pete for his work in making all of this a reality. I hope the camp folks and campers continue to appreciate it for many years to come. Who knows, maybe it will end up being responsible for injecting some new blood into the industry we hold so dear!

  • Chuck Gennaro

    Prisms into a CRL SMP? I bet it doesn’t sound too bad either 🙂 Super job!
    This stuff is important if we’re not going to be the last generation of broadcasters.
    So what do they do over the noon hour and on Monday mornings, sign off? Please not “voicetracking”, lol.

  • The Other Rob

    Fine bidness! It is good to see somebody pushing hands-on tech for kids. It’s the right way to learn, the right way to build enthusiasm.

  • John Mouw

    Very nice story.

  • Very good an FM station that meets part 15 rules and goes the entire camp ground. I’d like to see more of this type of thing. Maybe it will show the need for hobby Radio to the FCC as it does teach young and old about Radio. Wish I could be there to check it all out. Fun stuff reminds me of my WOCR in Olivet, Michigan days.

  • Tim

    I would venture to say there is zero chance that this meets FCC regulations in reference to allowed field strength of 250 uV/m at 3 meters as required by the Part 15 rules. .2 watts into a dipole? No way that’s going to be legal. Someone should get out there with their FIM-71 and check that out.

  • John Mouw

    Maybe Ralph Barlow from the FCC came by, did an interview and had his boys “tweak” the station for “substantial” compliance.

  • Paul Thurst

    Sure, Tim. I’ll get right on it! By the way, in your spare time, perhaps you could calculate the transmission line loss, that would be an interesting data point. Also, what is the return loss on the home made dipole antenna? Any ideas?

  • The only thing the FCC is interested in is whether or not an unlicensed system using the 88-108 MHz band and subject to their jurisdiction meets 47 CFR §15.239, for the maximum radiated field at a distance of 3 meters from the transmit antenna. Transmitter output power, coax loss and antenna gain all are irrelevant to §15.239.

    Also – there is no provision in Part 15 for unlicensed use on a camp or campus for intentional radiators to produce greater field strengths in the FM broadcast band on a campus than otherwise — as is possible for AM broadcast systems under §15.221(b).

  • D.

    Great, inspiring article.

  • Tim

    Paul, it wouldn’t take you long with a FIM. If you’re legal Part 15 FM and getting out more than a couple hundred feet you’re not legal. 250 uV/m at 3 meters is not a variable. The laws of physics tell us that field strength can only go so far. So tell us then, how this installation of a non-certified FM Part 15 transmitter was tested for compliance? The ONLY specification the FCC requires is a FS reading at 3 meters, and that it be at or less than 250 uV/m. Yes, it’s entirely possible that you have a line and antenna system that is so lossy that this is legal. But as was stated above power output, line loss, etc are of no matter. It’s the actual field strength that counts. Experience by many Part 15 broadcasters using certified transmitters has shown that much past 200 feet is simply not possible. You may get a bit further if on the receiving end there is a very high quality sensitive receiver with a good antenna. It’s pretty easy to calculate line line loss — give me the frequency, type of coax, length, and I’ll let you know. Return loss on a home made dipole can be quite minimal depending on the work done. Nonetheless these factors are moot as far as the rules are concerned. Legal FM Part 15 field strength will only go so far.

    I’m not trying to be an ass here, just pointing out that 250 uV/m at 3 meters – the legal limit, is not enough field strength to cover an entire “compound” unless that compound has a radius of about 200 feet with the transmitter at it’s center.

    Tim

  • Paul Thurst

    Tim, I know how to calculate line loss, I was being sarcastic. I was trying to point out that your statement of “I would venture to say there is zero chance that this meets FCC regulations” was made with you not knowing all the variables associated with the issue.

    You also completely missed the point of the story; taking something that was almost certainly out side of the regulations and capable of causing all sorts of problems (in band interference with other FM stations, out of band interference with Aviation and other services) and cleaning it up. It may or may not be fully compliant with the FCC rules, I don’t know. In light of the FCC’s new direction on field enforcement; e.g. not doing it, it may be incumbent on us, the people out the in the field, to make sure that these type operations at least do not interfere with others.

    If you are not trying to be an ass, then try harder. I will pass along your recommendations of making field strength measurements with a FIM-71 to the person who is involved with this (I am only writing about it, I did not do any of the work). In two weeks, the camp closes and the whole thing gets shut down anyway. Perhaps next year, the camp management will bite the bullet and convert to some sort of WIFI steaming system instead of the unlicensed FM band stuff.

  • Al Peterson

    “By looking at the sign up board, it seems that radio can still be very popular with teenagers.”

    And that nobody wants to get out of bed before noon on Monday. I can sympathize.

  • Tim

    I’ve been quite involved with Part 15 broadcasting for the past couple years and working as a commercial radio broadcast engineer for over 40 years. I’m presently doing testing of a variety of certified FM Part 15 transmitters. So far, none of them, in open space, gives reliable reception past 200 feet. Barely 250 if you can walk around with the radio and find the sweet spot and position the radio/antenna just right. But I’m going to test them to see where they fall on the 3 meter field strength rule — my guess is they may be under the limit allowing for a margin of error to be sure they’re legal.

    Yes, I’m certain the previous setup was indeed out of compliance and I’m sure the revised system is far closer to what is legal. I’m all for the kinds learning about radio, and I’m especially in favor of independent localized broadcasting, so don’t get me wrong. If they’d like to accomplish this mission I might suggest use of a certified Part 15 AM transmitter. Depending on conditions you can get a mile out of one without too much trouble. My AM Part 15 does that easily during the day, but I live in the boonies far away from much man made noise so a weak signal can be heard pretty well during the day. At night it’s an entirely different matter when the AM skip comes rolling in 🙂

    Just trying to prevent them with any troubles with the FCC. Usually it’s not the FCC who discovers a violation and goes after someone — it’s another station, often a commercial station trying to stop “competition” (and yes they often consider Part 15 to be competition) who complains, or someone from a music licensing group finds out and things go from there. Or it’s a group of Hams out to save the world by shutting down another “pirate”.

    Tim

  • Chris R.

    Lately, it’s been “no complaint, no problem” with the FCC. The reason why people have run ins with the FCC is that they do stupid things like trying to cover a whole city. Something like this, they would just want them to turn it off. Keep it clean and on your own property and chances are very good you will never hear from the FCC. BUT, they are not kind to repeat offenders!

  • I was wondering when the “Part 15 Police” were going to show up and piss on everyone’s cornflakes. Good gawd we all know the part 15 rules. This is a great story about getting the next generation interested in radio. If you ask any young person these days what they listen to they will tell you Pandora or Spotify. Radio is dying and anything that shows the younger generation there is something else is a big help. This does just that plus makes sure that this operation is not spewing crud all over the band. And if a commercial station is afraid of a part 15 station stealing a handful of listeners then they better take a look at their own house an see what they’re doing wrong. These days probably plenty.

  • The discussion thread just goes to show that the FCC rules for part 15 FM are beyond ridiculously restrictive.

  • Chris R.

    I have a 1/4 ground plane (in the basement!) and one of those ramsey FM 25 kits. What I did was adjust the output power until it just reached the property line (maybe 100 FT at most) and called it good. The signal checked clean and I used this for several years and it’s on only when in use. No idea what the FS is at all.

    Good to see that equipment put to use along with someone with the knowledge to set it up willing to do it.

    Paul , do you have the details on that antenna?

  • Paul Thurst

    Chris, it is a dipole made of 1/2 inch copper pipe. Pretty simple really, two pieces cut to f(MHz)/234, center insulator is PVC. I will see if I can get a picture.

  • Nick Straka

    With all of the pirates clogging up the band with dirty transmitters, overmodulating, sitting in someone’s IBOC carrier (the 95.7 in NYC comes to mind, among others) and generally trashing up the band, to be worried about this little station that covers a campground in the middle of nowhere CT is quite ridiculous.

    Is it FM Part 15 compliant? Of course not because the Part 15 rules for FM make it all but useless unless you want to transmit only across a room.

    This is positive, it’s getting kids interested in radio, and it is being accomplished with minimal interference and impact.

    If this thing doesn’t go much beyond the campground, who is really going to complain about hearing a bunch of kids on the air????

  • Jake

    I’m only curious to know how you (or whoever assembled this station) managed to find CRL Systems gear and Texar (Gentner) Audio Prism’s. I too have a ‘compound’ I’d like to broadcast to. Furthermore, should anymore of it find its way to a dumpster, or resting collecting dust in a backup back shelf, please reach out, I’m interested.

    I realize this is a two year old blog/thread, but, perseverance is just another form of stubbornness and I’m quite stubborn.

    (Admin note: I like your style. I will leave the e-mail addy un-redacted)

    mbkserver (at) gmail [dot] com

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