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An FM Broadcast Transmitter For Your Home
Bruce Perens writes "I wanted to be able to listen to net audio and my ham station around the house and yard. Those iPod FM transmitters don't have enough range. So, I bought a digital controlled, 100 miliwatt transmitter that covered my whole block the first time I plugged it into what was, until then, a recieving antenna."
So what kinda receiver do you carry around that's more convenient than an ipod?
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Some people are good with words, others,
The VHF broadcast band is a regulated resource. What you have created is, in effect, a pirate radio station with all the regulatory and copyright issues that that entails. If the FCC/Ofcom or whatever regulatory authority covers your area doesn't take an interest in your "personal radio station" in fairly short order, I'll be very surprised. The performing rights organisations may take an interest, too.
In short, you will be very lucky if you get away with this for long.
Resistance is futile. Reactance buggers it up.
If you just want a radio station in your home it would seem to make more sense to use a Carrier Current transmitter. What this guy is doing is pretty damn illegal and if you do what he did you can be looking at tens of thousands of dollars in fines!
From what I can tell anyone can setup a Carrier Current station(check for yourself), you can find some pretty cheap kits.
This guy doesn't seem to be all there, he says he has a HAM licence, but is stupidly violating FCC laws. He also says the thing has a BNC type connector but the picture looks like a type RG6 connector.
As mentioned here, the unit is not FCC approved. Once this guy comes onto the radar (by a slashdotting, for example) he might well get a call from the FCC.
How exactly does ones ability to learn morse code relate to ones technical skills?
Its one of those BS arguments you hear all the time about morse code.... Its like saying that they are less technically savvy since they don't even have to be able to speak spanish anymore.
I do agree with you on the technical exam however, I think it is e.g. a good thing to require a HAM to be able to explain WHY morse code is a good mode.
Jeroen
Secure messaging: http://quickmsg.vreeken.net/
The FCC has monitoring stations throughout the U.S.
And for many areas without stations they are quite infamous for little black vans with lots of antennas on top and very small white letters that say "FCC"
The FCC are not idle people, and they not only track you down (if you are radiating RF it's emberassingly easy in case you didn't already know), but they confiscate your equipment also, and you will not see it again. Also, you might have to come up with serious cash for the fines.
Contrary to what you might think, they still chase after CBers with illegal amps too.
I'm someone with a ham license, and am somewhat disappointed with Bruce for advertising something like this, as it goes against the ham ethos of responsible use of technology (esp. radio). If not for his own sake, but for others that will ignorantly decide not to go with the seemingly innocent 100mw version, but those who decide bigger is better and move up to 3 watts, which blows the doors off part 15.
I say seemingly innocent, because if you pump this out your standard home fm antenna as suggested by some, these are almost always a yagi that has gain and will certainly exceed the 250uW at 3 meters.
If enough of these pop up, you can count on NAB to become the next dirty acronym on slashdot, as they become more proactive in squelching (pun convenient) the competition. Except that these guys have a vast amount of caselaw/FCC resources to help back themselves up with.
I truly believe that there is a need for Low Power FM broadcasting, contary to what NAB and NPR propaganda tells you. But breaking the law rather than working to change it is not the way here.
I can't help but wonder if Bruce didn't confuse AM Band with FM band concerning power levels. Without pulling out my calculator, I don't see how 100mW can be legal for FM unless you are using an extremely long length of coax. I believe that the max you can have going to the antenna is around 1 mW.
I hate to take of the rose colored glasses on this one, but it's a bad idea all the way around.
"How exactly does ones ability to learn morse code relate to ones technical skills?"
I don't think it does, but removing the morse requirement would tend to make HAM similar to CB radio in some people's eyes.
Incidentally, I had to fight the temptation to try and answer in morse...
"I think it is e.g. a good thing to require a HAM to be able to explain WHY morse code is a good mode."
And not actually know morse?
Oddly Draconis
Too cynical to live, too stubborn to die.
You forget, Bruce, that we in the UK have the 70MHz band which behaves in a similar fashion to Band II VHF. Propagation, even at these frequencies, can occur via Sp-E and tropo-ducting. Your valley, if it is a valley, is an ideal setting for a temperature inversion-type tropo-ducting event (apologies to non-radio types - I'm not going to explain the mechanism, it would take too long).
;-) ) should be treated with respect. That means regulation. You'd be far better off using unlicensed spectrum and building/buying something more suitable for the job. It's OK if it's just you doing this, but can you imagine whole streets of folks running their own transmitters? Not likely, I hear you say. Well, so what? The *theory* is the same. Otherwise, the *possibility* exists for folks driving around listening to Band II picking up a new station on a particular frequency every few hundred yards. If I can see this, you can bet the FCC can too. That they have dropped the limit from 100mW to a field stregth at the boundary (according to posts on here) means they've already taken a look at the problem.
Point taken on the bandwidth, the power being spread between the components of the sidebands. You also make a good point on the capture effect, but for my side. The way this works, using inverse square law, is that anyone in your immediate vicinity is going to receive you rather than a transmitter using significantly more power but significantly further away.
I still think this is a poor idea to project to the masses. Radio, especially in the broadcast bands where it upsets more than a few zany techie types (we amateurs
Over here, one strike against you with regards the Wireless Telegraphy Act (the all-encompassing law that governs radio in the UK, passed in 1949 and amended in 1988) and you lose ALL your licences until the Rehabilitation of Offenders Act kicks in. For me that is three, for five years minimum. One professional, one marine and one amateur, the former two being a huge problem if they were lost. How about you? Is it a chance you're willing to take?
Resistance is futile. Reactance buggers it up.
Ok, so you willfully violated FCC regulations by transmitting with an unlicensed transmitter in the FM broadcast band in excess of the allowable ERP for unlicensed transmitters.
You also put you amateur radio license in jeopardy.
Any person off the street might violate the unlicensed transmitter ERP and plead ignorance. Anateur radio operators are supposed to know better.
I was really suprised to look at the poster and see it was Bruce.
. there used to be a sig here.....
/. does not let you do a full reply in .- .-- .--
morse.
onepoint
if you see me, smile and say hello.
I bought one of those little consumer FM transmitters (this was a Belkin model) that you're supposed to plug into the audio jack of your MP3 player, but it really sucked. The main issue is that reception was so bad it was unacceptble even if I put it on top of my car dashboard.
So, since the thing was so useless I was out thirty five bucks anyway, I took it apart. The antenna turned out to be a length of wire about two inches long stuffed into the same cable used for the audio jack. Obviously, this was nearly worthless. I drilled a small hole in the case and soldered in a piece of wire the right length for a half wavelength antenna -- a little less than 63 inches for the low end of the FM band. As a result, I can now broadcast all over my house.
Now, since I was using it in a car, a five foot piece of wire was a bit unweildy, so I wound it around a pencil to make a loopstick antenna. I don't know anything about designing loopsticks, but it still worked OK for broadcasting around the house. Basically, I'd guess just about any length of wire a few feet long would work way better than the tiny length of wire they were using.
The only remaining issue is that the volume is very low; you have to jack up the volume on your receiver nearly all the way to get acceptable listening levels. If you're planning on driving around town with your windows down so your car's subwoofers won't blow them out, this is not for you. Also, the sound is a bit muddy. I suspect that in order to avoid any FCC issues, they took a number of steps: using a low transmit power, using a worthless antenna, filtering out the high end audio frequencies, and undermodulating the signal. I could probably desolder and replace some resistors and capactitors or something if I were motivated enough to analyze the circuit. Plus, as an old fogie I'd have to learn to deal with surface mounting (I learned to solder on bakelite terminal strips for chrissakes). Altogether this is too much trouble.
I'd recommend that if you bought one of these consumer MP3 transmitters and found it totally worthless, then you should replace the antenna with any old piece of wire and it will gain enough range to be some use to you. If you haven't bought one yet, don't. Getting a device like this guy is using would be a bit more expensive but probably a lot more satisfactory.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
A ham radio license gives you no special rights outside of the ham bands. (And yes, I have one too.) Last I checked, the FM broadcast band (88-108 mHz) is outside the ham bands.
even if he were using the ham bands, it's illegal to broadcast music over them, unless it happens to be incidental music from a rebroadcast from the Space Shuttle (yes, the regulations are that specific :)
The (part 15) rules do permit low power transmitters on the FM broadcast band, but they're based on effective radiated power (i.e. in the direction with the strongest signal), not total radiated power. Specific regulations here. If your signal can be picked up in your entire neighborhood, you're obviously exceeding the power limit.
Sounds like Bruce doesn't understand the regulations very well. He may not be abusing the ham bands, but the FCC can certainly take away his ham license for it. They probably won't for a first offense, but the odds are very good that this article will be all that's needed to get *somebody* to send in a complaint, and the FCC is likely to send him a nasty letter and require him to respond (that's how they do things.)From the article --
He's right -- that's probably a good deal under 100 mW of power, especially with his good antenna. So if he's only turned it down to 100 mW, he's violating the law. But maybe he mispoke