Low Power Radio on Amazon

All the fun of low power radio with the service and satisfaction guarantee of Amazon. Please visit our
Amazon Search Page
to find low power radio gear!

Scosche FMT4 transmitter update

Scosche transmitter & NOAA receiver. Added
antenna wire forms dipole with audio lead
A quick four years and three residences ago I set up a little NOAA Wx re-transmitter, broadcasting weather info to a few dozen neighbors for fun.
     The technology for that project included an old scanner, an old guitar compressor complete with foot pedal and a very slightly hacked low power FM  transmitter/car adapter from a big box store. 
     The Scosche FMT4 RA transmitter, for around $20.00, provided a bit of extra fun if a short wire (say, a quarter wavelength, for example) is attached to the negative battery terminal.
    Why would that have any effect?   As the circuit diagram shows, the manufacturer used a common, cost-cutting shortcut of connecting the antenna to the audio cable for a handy antenna and connected the RF ground to the ground bus on the PC board. 
     As this was intended to be a battery powered device, that should be the end of it.  The RF out is cleaned up with a capacitor / inductor first order filter before connecting to the audio cable and the RF ground ends at the bus.

Circuit diagram of the RF pins on the transmitter IC
     Unless, that is, someone puts a 1/4 to 5/8 wavelength wire (60" - 74" @ 100MHz) on the negative battery terminal, creating a radiator on the ground side of the transmitter and forming a crude, poorly matched dipole.
     Add a battery eliminator made from a recycled cell phone charger and you have an instant 24/7 operation.
     After four years of delivering NOAA Wx in a more convenient form, the original unit finally went buzz, crackle, hum and fell silent.
     Fortunately, I like the '4RA unit so much I bought two at the time so I had a back up transmitter I could put in service.
     There was some question as to how rugged these units might be when first discovered, now we have the answer - about four years of continuous use - two years longer than this model was on the market.  The FMT 4 RA was superseded by the FMT4 TFM in 2011.  The new model dumps the bank of micro switches for a progressive push button cycle when choosing frequency
     You can read much  more about this $20.00 ticket to low power radio fun in our "Freedom Stik" post.
Scosche FMT4 tuneIN Universal
FM Transmitter for iPod/MP3 Player
or broadcasting

No comments:

Get on the Air with One Click, Buy a Transmitter Bundle from Amazon.com

Many hobbyists agree that the F-S variable power 0.1 to 0.5 W FM Transmitter is one of the best transmitters for the price.  Add the convenience of a selection of premium quality accessories and you can literally be on the air with a single click.
     No need to search the web for FM broadcast antenna, FM transmitter antenna plans or FM broadcast antenna diy, this great combo includes an F-S Electronics RangeBooster 2.0 Ground Plane Antenna. 
     Connect your antenna to the transmitter with your included ultra low-loss  (55.4 db/100m), 8 mm diameter,  rugged class 8D broadcasting cable and add your programming with the included 6 foot heavy duty stereo audio cable. 
     Necessary adapters are included, too - a simple and cost-effective solution to increase your range, minimize signal loss and maximize your broadcasting enjoyment.
     Peace of mind with the lifetime warranty.

Check out these reviews from real users:

• "All components of the bundle are high quality."
• "The Rangebooster antenna definitely extends the range"
• "Signal goes through brick-metal buildings and embankments as if they were not there"
• "The transmitter unit defaults to .1 watts which is how I've been using it."
• "I am able to get more range with the external antenna"
• "Set up was so easy. The sound quality was awesome. I love this transmitter!"
• "The transmitter works well given I am out in the 'bush' away from town"
• "Worked great right out of the box. Very pleased!!"
• "It is a very compact and easy to use transmitter with impressive stereo fidelity"

So quit wishing and waiting, quit struggling with inferior approaches and “Git er dun!”
Click below to order direct from Amazon.com
Bundle Deal #1: F-S 0.1 - 0.5 Watt Long Range FM Transmitter, RangeBooster 2.0 Professional Grade Antenna Kit, Broadcasting and Audio Cables ($300 value!)

Bundle Deal #2: 0.5 W Fail-Safe Long Range FM Transmitter FS CZH-05B + Rangemax 1.0 Antenna ($200 value!)
Bundle Deal #3: Fail-Safe 0.5 W Long Range FM Transmitter + 1/4 Wave GP Antenna Kit ($200 value!)
Power Blaster Bundle Deal #4: Fail-Safe RangeStud 15 WATT FM Transmitter + RangeMax Professional Grade Antenna ($400 value!)