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I like to use this ABM1 - Passive Air Band Monitor when flying. I keep it discreet as I'm sure most flight crews won't understand how it's different from a typical radio receiver. I regularly hear that "bzz bzz bzz" of cell phones with this device. I then ask my girlfriend sitting next to me if she put her phone in airplane mode. If she hadn't and does it the noise usually goes away. If she had her's in airplane mode then I assume it's someone else sitting near me.

Correct so far.

Phones do cause interference in the aircraft frequency bands (at least at short range).

And... you go off the rails.

GSM phones cause interference in audio-frequency circuits because the phone transmits in regular bursts every 4.62 ms (this is why it doesn't affect CDMA, UMTS, etc., only 2G GSM/GPRS/EDGE, because they use TDMA). It turns out audio amplifiers generally tend to serve as decent wide-band AM receivers, so this is very easily picked up as a 217Hz buzz. However, this is all happening on the audio-frequency side, so calling it "interference in the aircraft frequency bands" is just plain wrong -- it will affect practically any unshielded or insufficiently-shielded device (it's only a couple watts or so transmitter, but within a meter or less the inverse-square law says you do need better shielding than a lot of consumer electronics have) with an amplified audio output, including all sorts of radios, and non-radio devices from MP3 players to cassette players.

(for more on this, google or start here)

Fortunately, it's a really easy problem to solve -- just keep your phone out of the cockpit. Thanks to the inverse-square law, it's really only a practical issue at very short range.

I like to use this ABM1 - Passive Air Band Monitor when flying. I keep it discreet as I'm sure most flight crews won't understand how it's different from a typical radio receiver. I regularly hear that "bzz bzz bzz" of cell phones with this device. I then ask my girlfriend sitting next to me if she put her phone in airplane mode. If she hadn't and does it the noise usually goes away. If she had her's in airplane mode then I assume it's someone else sitting near me. Phones do cause interference in the aircraft frequency bands (at least at short range).

Or they can have Faraday cage boxes made up and pop the phone into a box as part of the standard procedure of picking it up.

They don't even have to have them made up. RF-proof enclosures are readily available off the shelf for a (relatively) low price.

I got myself a ramsey fm transmitter from here and hooked up a cheap dedicated PC with my 3 terabyte music collection and I can hear my music from anywhere in the house or outside on cheap fm radios.

Sometimes people over think things.

Check out back issues of Electronics Now and Popular Electronics magazines. The articles are detailed and fun. Unfortunately they went out of business. However, there are still a few mags out there, such as Everyday Practical Electronics.

A good way to get some chops is to build some kits. By far the best is Ramsey Electronics. I also like Information Unlimited; they have a lot of high-voltage and other stuff. Quite an amusing website if you dig around.

Set up an area, because most anything you do will take time and if you want to get serious about the hobby you'll need a workshop away from wifes (oops, slashdot, not applicable) and kids, pets, etc. You might want some smoke removal for the solder as well.

I built a cheap FM transmitter from a hobby kit and use existing FM receivers in my house to listen (and have a $5 thrift store boom box to go outside).

Yeah, there's a ton of variety out there. Good toy stores (like the one in my sig) have everything from those little block kits to the 500 in 1 electronic springboard kits (remember those). I think you might be looking for something a little more advanced.

I remember putting together a few kits from Ramsey Electronics, including the venerable FM10 stereo FM transmitter. They have a lot of interesting stuff there. Also Information Unlimited is a classic for fun stuff like high-voltage, etc.

Ramsey Electronics has a decent range of kits covering all sorts of subjects and skill levels.

Try Ramsey Electornics, they sell some nice kits. http://www.ramseyelectronics.com/

Ramsey Electronics

Great radio projects - one of the best ones for aviation! Other stuff too and they explain the circuits and how to modify them if you want.

The best way I've found is to use a small FM exciter. The Ramsey FM25B works great!
http://www.ramseyelectronics.com/cgi-bin/commerce.exe?preadd=action&key=FM25B

You will have to assemble it yourself but if you've done any soldering it should only take 5-7 hours. Tune it to an open frequency,
set your output levels and listen on any FM receiver.

I wired it with an input selector to my pc and satellite receiver but you can also connect it directly to your portable mp3 player.
I typically use WinAmp to play from my library or something from ShoutCast.

If you live in a very congested area (apartments) you need to be careful to not step on any commercial broadcasters.

I really can't believe that no one has stepped up to replace them. You would think that there would be a decent-sized market out there.

What about Ramsey Electronics?

--Rob

Here

Ramsey Electronics will sell you a 50 watt LPFM Radio Station In A Box for $4000.

The price of a single high-end laptop. The non-profit may want to reach the audience that doesn't have dial-up service, much less WiFi or broadband cable: the poor, the elderly, the disabled, etc.

These types of kits are still available - just not from Radio Shack. I maintain a concise list of kit (and part) sources. It includes several sources for these type kits, including Ramsey Electronics, which has the "Super-Fun 130 In 1 Electronics Lab" [item PL130], the "Complete 300 In 1 Electronic Lab" [item P300] and the " Advanced 500 In 1 Electronic Lab" [item PL500]. -allen

Ramsey Electronics sells 50 watt LPFM stations in a box starting at $4000. Low power demands. Instant set-up. Freedom from interference.

That powerful AM radio station may be trying to provide regional or multi-state coverage when you need something much more focused. That is the FM advantage.

Get an FM transmitter, broadcast your MP3s, listen on any fm radio anwhere in a 1 block radius.

http://www.ramseyelectronics.com/hk/default.asp?pa ge=amfm

I've an earlier version of the FM25b. I can listed to my MP3s on any $9 FM radio.

My stereo isn't in the same room as my main listening speakers. I have the stereo downstairs in the family room. Upstairs in the living room I have a pair of (reasonably high quality) bookshelf speakers mounted on the wall and a subwoofer. I use a remote repeater to control the volume and selection on the reciever downstairs. So far so good - I can switch sources and control the volume and CD player from upstairs.

So then I have my media computer also downstairs hooked directly to the stereo through the sound card outputs (yes, I know the squeezebox high higher quality outputs, but I can't tell the difference between playing off the computer and a CD, really).

So if I had a squeezebox I couldn't see the display because it has to hook up to the line inputs on the stereo (at least according to the diagram on the web site). So what I would need is a remote head unit that I can put upstairs to control the box hooked up to my stereo. I didn't dig too deep on their web site, but I didn't see it. What I've done to solve this problem myself is to write a web interface to AmaroK so I can control the songs from our ibook that's upstairs. This gives me maximum control for minimum visible equipment.

For listening to the TV, I picked up a Ramsey Electronics FM transmitter and hooked it up to the TV out. Then I tune the radio downstairs and voila! It actually sounds really good - much better than you would think (the FM is not compressed, unlike your basic radio station).

Check out Ramsey Kits. They now have a digital FM stereo transmitter kit for sale (very cool). Specifically look at this page. I see three FM broadcast kits other than the one mentioned above. They cost $45, $140, and $270.

http://www.ramseyelectronics.com/

The equipment you need to feed a radio signal is somewhat bulky and expensive.

Not so. You can fit a transmitter that will broadcast to the entire Astrodome, and several city blocks around it, in the palm of your hand.

Heathkit is gone -if not forgotten- but there are alternatives: http://ramseyelectronics.com/ , for example!

You probably want a Stereo FM Modulator.

Ramsey makes and sells kits like this one for home/hobbyist use.

USE THIS DEVICE AT YOUR OWN RISK -- I'm not taking the heat if you end up with an FCC fine. They're legal devices, but they can be used illegally if you turn up the power too high, so make **SURE** you understand the regulations that cover the use of these things before you plug it in.

Ramsey Electronics Has tons of DIY FM kits, and even some very high end professional equipment.

They also have tons of other hobby kits for electronics.

It is absolutely untrue that unlicensed transmitters at 100mW or less are legal in the FM broadcast band in the U.S.

Well, actually, it is true that some unlicensed transmitters at 100mW or less are legal in the FM broadcast band. But only those that operate at far, far less than 100mW.

I'm really surprised that the person who wrote the original article (i.e., the one who posted on technocrat.net) admits to being a ham operator, but then seems to know nothing about part 15 of the FCC regulations. If you want to know all about the limitations on unlicensed operation, you need to know part 15 -- no excuses. And the 100mW limitation applies ONLY to unlicensed transmissions in the AM broadcast band, and NOWHERE ELSE. Instead, each band in which any kind of unlicensed transmission is permitted is subject to its OWN RULES.

See: FCC rule regarding unlicensed operation in the band 88-108 MHz (Note that although this document is served by akamaitech.net, the source of the document is the U.S. Government printing office)

FCC PDF document with all you ever wanted to know about unlicensed operations under Part 15

Ramsey Electronics kit page with FCC information regarding lawful use of low power transmitter kits

American Radio Relay League (ARRL) information on part 15 of the FCC rules (The ARRL is the largest national organization for ham radio operators)

Note that the actual permitted field strength for unlicensed operation translates into the a signal of only a few nanowatts -- around the single digit range -- certainly not anything even remotely resembling 100 milliwatts!

Thus, the immediate parent of this comment should be modded WAY down -- it certainly isn't "informative." If anything, it is perpetuating misinformation that could get someone into serious trouble.

Especially when you can go with one of these for a fraction of the cost. True, a little modification may be necessary, but hey, we live for that sort of thing, don't we?

Ramsey has what looks to be a gret new kit - see here:

http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=FM30

I have this one already and, though large, it is excellent.

http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=FM100B

Ramsey has what looks to be a gret new kit - see here:

http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=FM30

I have this one already and, though large, it is excellent.

http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=FM100B

What you want is something like this . Plug it into the sound-out of a cabled media computer (or, heck, a Wireless Music/Media Player, if you feel the need to comply with the latest buzzwords). Put the computer wherever you have the space (closet, basement, attic) and keep your stereo clutter-free. Tune the FM transmitter to a free space low on the dial (89.3 or so), and listen to your streams on any stereo in/around/outside the house. So long as you aren't stepping on any other nearby frequencies, and the reception drops off significantly enough before you get more than a few houses away, you shouldn't have much worry about complaints.

Or you can drag your Wireless Music/Media Player out into the backyard the next time you want to host a barbecue. Of course, "wireless" doesn't usually apply to power cables and wall warts.

Uh...

The FCC does exactly what you're talking about. It only regulates stations above a certain wattage, even on the broadcast radio spectrum.

You don't even need a license. Buy one of these and make your own radio station, man. It's easy. And with a few simple modes, you can double the range without irking the FCC. Place your antenna in the right place and you can get up to a mile of broadcast strength for your community station.

Or this if you've got some money available, or this if you've got a small budget, or this if you're cheap, or this if you're really cheap and don't care if you sound like crap and can't be tuned in.

Or this if you've got some money available, or this if you've got a small budget, or this if you're cheap, or this if you're really cheap and don't care if you sound like crap and can't be tuned in.

Or this if you've got some money available, or this if you've got a small budget, or this if you're cheap, or this if you're really cheap and don't care if you sound like crap and can't be tuned in.

Or this if you've got some money available, or this if you've got a small budget, or this if you're cheap, or this if you're really cheap and don't care if you sound like crap and can't be tuned in.

As for subversive news, the article mentioned Democracy Now, I've never heard that one, but I often catch Free Speach Radio News on Pacifica Radio's streaming audio, or if I miss it, download it from FSRN

If you need to cover a little more ground - say, two or three blocks in a city or half a mile in a less built-up area - part 15 AM radio can get the job done without requiring a license.

Mobile station? Did that, several times.

TV production company I worked for used to take the mobile production truck on long trips. We bought a stereo FM transmitter, used an existing mixer, had headsets, and played our personal MP3 collections. We'd put somebody's cell number on a poster on the side of the truck with the frequency we were broadcasting on, and took requests. We chattered like (bad) DJ's, sang along, and talked to those around us listening. We even put a wireless mike in the chase car, so we could all play along.

Our range was typically about 1/2 mile, so we rarely had more than 3 or 4 cars listening. I tell ya, though, it was a real hoot getting that first request!

Posted anonymously to protect the guilty.

Where you want to go wireless is in the FM band. Something like this.

Plug it into the sound-out of a cabled media computer. Put the computer wherever you have the space (closet, basement, attic) and keep your stereo clutter-free. Serve the jukebox control interface via http on the local wireless network and control it via laptop, pda, whatever. Tune the FM transmitter to a free space low on the dial (89.3 or so), and listen to your streams on any stereo in/around/outside the house. So long as you aren't stepping on any other nearby frequencies, and the reception drops off enough a few houses away, you shouldn't have much worry about complaints.

If you're interested in music around the house, might I suggest a low-power FM transmitter?

Then you can buy cheap receivers, and put them all over the place, and listen to the music that's on your server.

Virtually no server configuration required! And if you time it right, you can have it play your theme music while you pull into the driveway ;-)

What you'd need to do is get a tiny camera from somewhere (like this or this one). Then you'd attach it to a strong tini transmitter (like this one) and hook it all up to a battery. Instant spy kite. Not that a kite above a compeditor's company all day every day with no one flying it would ever look suspicous. Still might be too heavy though.

What you'd need to do is get a tiny camera from somewhere (like this or this one). Then you'd attach it to a strong tini transmitter (like this one) and hook it all up to a battery. Instant spy kite. Not that a kite above a compeditor's company all day every day with no one flying it would ever look suspicous. Still might be too heavy though.

What you'd need to do is get a tiny camera from somewhere (like this or this one). Then you'd attach it to a strong tini transmitter (like this one) and hook it all up to a battery. Instant spy kite. Not that a kite above a compeditor's company all day every day with no one flying it would ever look suspicous. Still might be too heavy though.

For what it's worth, many years ago when I crossed paths with some cell-phone product design types, there was a hybrid product concieved, originally to improve service and battery life -- a pager/cell phone. (We're not talking SMS here, but plain old POCSAG paging.)

Anyway, with this approach you could work if you wished to retain positional anonymity -- have a conventional pager (which is just a reciever) notify you of calls, then choose to power up the cell or not.

As practically every other post has pointed out, positioning by radio has no requirement of GPS being present. Any transmitter can be position located. Amateur radio opertators actually have contests to do this -- foxhunts -- and the equipment to do position finding of non-spread-spectrum tranmitters is pretty trivial to make or buy.

If you want your whereabouts to remain unknown, don't transmit. Simple as that.

Well, first I'd point you at the Amateur Radio Relay Leagues's website - www.arrl.org.

That said:

You need to lock the problem in a bit more. If you are just looking for FM radio LO's, you'd be looking in the range of about 70-125 MHz (assuming 10.7 MHz IF, high and low side injection).

For an omnidirectional antenna, you'd be looking at a discone. For a directional antenna, that wide, you'd probably want to use a log-periodic as a yagi would be too narrow band.

Then, if you are looking for signals, a sensitive spectrum analyzer or communications service monitor - I'd suggest looking for a used IFR-1200S, IFR-1200Super, or IFR-COM-120B, but I'm biased as hell since I helped design the 120B. Check eBay (gag). Don't buy a 1200 dash-nothing or 1200-a - it does not have the spectrum analyzer in it. If you can find a 1200SRA that would be even better, but I don't think No Such Agency has given those up.

For DF work - IF you get a strong enough signal, then you can use something like a Ramsey electronics kit DF rig. You can also look up Fox hunting for more information.

Simplest way to scratch that itch - Get a ham ticket, find your nearest club, and sit at the feet of the Elmers.

You'll probably find that, even with light traffic, 802.11b is going to be too slow and unrealiable for 30fps streaming video...

Since you are going to output to a TV anyway, why bother with computers/802.11b and broadcast directly using a small TV transmitter. I would have expected Ramsey to have a transmitter kit, but all they seem to have these days is a semi-cheesey 'cube' transmitter. Even so, the high powered version might be good enough for what you are looking for, especially with a good antenna.

A quick Google search turned up some other kits. Most of these have a fairly short range, but with good antennas, they'll easily transmit further (and with higher quality), than compressed video over 802.11b. Plus, if you get a kit, building it can be a nice little project for an electronically minded student.

You'll probably find that, even with light traffic, 802.11b is going to be too slow and unrealiable for 30fps streaming video...

Since you are going to output to a TV anyway, why bother with computers/802.11b and broadcast directly using a small TV transmitter. I would have expected Ramsey to have a transmitter kit, but all they seem to have these days is a semi-cheesey 'cube' transmitter. Even so, the high powered version might be good enough for what you are looking for, especially with a good antenna.

A quick Google search turned up some other kits. Most of these have a fairly short range, but with good antennas, they'll easily transmit further (and with higher quality), than compressed video over 802.11b. Plus, if you get a kit, building it can be a nice little project for an electronically minded student.

Actually, for most bands (IE: CB), you don't need a license as long as you don't transmit over a predetermined power (4watts for CB). You can actually transmit legaly on the FM radio band (88-108Mhz) up to 1 watt. Ramsey sells several transmitters for doing this. Some can be easily modified to go over the legal limit for use outside the US. They are used alot for things like drive-in theaters and by realtors for "talking houses."

When you can check the weather by going outside http://www.ramseyelectronics.com/cgi-bin/commerce. exe?preadd=action&key=ws5000

Lan Pipe is very cool, particularly if the house is correcly wired with Cat5.

But what if you don't have wires already? FM is MUCH cheaper!

Uses your existing home FM radios recievers in every room, or your walkman. Simply add one of these to your music server, and no pulling cables.

$39.95 FM solution, or that
$189 FM solution.

First person to say "Knoppix" on slashdot?
Mac Refugee, Paper MCSE, Linux wanna be

Lan Pipe is cool, but what about a simple to use Music Server?
Someone please tweak Knoppix boot CD OS into a music server!

PC with, bootable CD drive, as well as Nic and sound cards. Hardisk with digital audio files, normally mounted read only, so hardpower off is no problem.

Samba and Netatalk for music via file sharing and play list creation, and LAN Pipe. Xmms with RF wireless remote and relevant plug in. Also use a webinterface to control the sound card on the server via Xmms command line tool and Web Control interface

LanPipe is nice, but FM Broadcast is MUCH cheaper. It uses existing home radios, and 1 piece serves all, and no pulling cables, with this $39.95 FM solution, or that $189 FM solution.

First person to say "Knoppix" on slashdot?
Mac Refugee, Paper MCSE, Linux wanna be