1 watt high power FM transmitter

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giantjoebot Posted: Tue, Aug 15 2006 4:06 AM
EDIT:
Due to presure form the UK government the site that I purchase this from no longer has it for sale on their site. Due to the possible legal issues I have removed most of the links and site names, and have re-posted this review after deleting it by a request. The links that are left are at the bottom.

Let me get some legal stuff out of the way first, but please don't let it scare you.

This was copied from site I bought this from, and the same applies to to this review as well.

"These are FM transmitters. They may be illegal for use in certain countries without an appropriate license.
Please read the warning note & full terms and conditions regarding them, and ensure you comply with the relevant communications laws of your country and use.

These FM Transmitters are sold expressly as for evaluation purposes only in the UK.

WARNING NOTE
It is an offense in some countries of the world to radiate electro magnetic waves at certain frequencies without a license. It is the Customers responsibility to check relevant laws, and regulations regarding their use and licensing before considering using any goods or services listed on this site.

The site does not condone the use of transmitters for illegal broadcasts, pirate radio stations or pirate transmissions or other illegal activity whether bought from this site or otherwise. Please ensure you comply with all the relevant laws governing the equipment and use in your particular country, and any relevant international law.

The site is not responsible for the use or intentional use of the products on this site. The Customer agrees to defend, indemnify and hold harmless the site, its employees and agents, from and against any claims, actions or demands, including without limitation legal and accounting fees, alleging or resulting from the improper or unlawful use of goods commissioned by the site."

Now with that out of the way I can tell you about this amazing extremely hard to find item.

Please read this review in full before purchasing. There will be vital information that you will need to know in order to properly utilize this item. Basically, if you read this you will avoid thee mistakes that I made, and it will save you time and money.

The search for a wireless audio

First let me explain why I'm writing this review. I had an idea about a year ago to broadcast music from my computer to my entire house. That way when I was getting ready for work no matter where I went I could listen to music. Same goes for cleaning and other activities that require going to multiple rooms. I rent so drilling holes all over the place wasn't an option, so it need to be wireless. So I started searching, and looking and different options. Many of which were very expensive. There were a few inexpensive FM transmitters, but they came as a kit. A kit is simply a circuit board with all the parts, and you have to suader it all together, and I'm told its not easy and should not be done by somebody that has not done saudering work before. In fact the majority of FM transmitters that I found were kits, and the ones that were already put together ran $200 USD and up. I ended up buying 2 Kima Wireless 900mhz audio systems (a clone of the US Robotics one). This worked well for a short period of time, but eventually they would only work sometimes. A lot of the time they would work until someone walked by, and then they would cut out for a few seconds. This drove me nuts. So I started looking again at FM transmitters, now willing to pay the higher price for something that worked. Then I found this little beauty that actually cost less then anything I had looked at before.

About the transmitter



cost 16.99 UK sterling or $29.63 USD
The antenna is sold seprately and cost 4.99 UK and $8.70 USD (you will need this)
There shipping cost to the US is very low!

Here is a copy of the descripton on thier site:

1-2 Mile (3.2km) Range Features:
NOTE: RANGE HIGHLY DEPENDS ON ANTENNA DESIGN, ANTENNA LOCATION / PLACEMENT AND OTHER FACTORS, AND IS CONSIDERED A ROUGH GUIDE ONLY.

# 1 Watts High Power FM transmitter
# Range - up to 2 Miles depending on antenna placement and land conditions and suitable antenna design. General expected range 2 miles. (3.2 km)
# Low Power Consumption - Less than 90 mW
# 12v-20v DC powered
# can be powered from any suitable 12v battery source.
# Variable Frequency - Adjustable FM radio Frequency from 88.0 FM to, 108 FM) internal
# low noise & low frequency spread
# Dimentions - Main Unit approx size of box of matches
# Operational LED

Now I tell you what isn't on their site:

This is a MONO non PLL FM transmitter. In case you don't already know a PLL transmitter is one that uses a micro chip for tuning. I will include links to STEREO PLL transmitters, but they will cost a lot more, at the end of the review. I was told by the site that they will have a Stereo PLL transmitter at some point, but it will cost around twice as much.

The 1 to 2 mile range that they describe is only if you mount an antenna on your roof, and I confirmed this with the site.

For the antenna it has a BNC jack

Its smaller than a CD, about 6cm by 8cm



Performance and features

There really isn't much tell about its features. Its a small black box with 2 wires for power, a mini male audio jack, and a BNC antenna jack. The device is tunable by removing the cover and turning a small screw. (I had to use a knife to tune it, but it was very easy to do, and easy to get the desired frequency). the only thing that came with the transmitter was a slip of paper with the frequency that it was set to, the polarities of the power cables, and a note saying to contact them with any issues, and that you can send it back to them for frequency and power adjustments for FREE.



Unfortunitly I did not purchase the antenna from their site. I thought that I might have something that would work like a stereo antenna or wifi antenna, but I was wrong. So I went down to Radio Shack and ended up spending over $30 on a BNC cable, antenna, and coupler. I was told by the site that this is not the proper antenna for this transmitter, and that it would reach much further with a proper one. I will go into more of the details in the next section. The point is that I was unable to test the true potential of this device, but even with the wrong antenna it works great.

I used a $5 sports radio from Walmart to test the distance. I used the same radio connected to a set of 2.1 computer speakers, and a boom box to test the sound quality (because thats how its setup in my house)



It reaches over 100 feet through 5 walls, one of them external. The reception is perfect. I have only had one time when I got 1 second of static, and that was in my bedroom on the other side of the house with the door shut, and the receiving radio was next to the AC unit, and had it's antenna fully descended. I just pulled the antenna on the receiver all the way out, and have not had it happen again. The sound quality is really good. Its not as good as the speakers that are directly connected to my computer. It sounds like a radio station with perfect reception basically. I have found one song that for some reason the vocals are not transmitted. I believe this is because the stereo output on my computer is changed to mono. At first I was worried that maybe only one channel was being transmitted, but when switching the speaker output fully to the left or right it still transmitted sound. So oddly enough there are a few songs that are not compatible with this transmitter, but I have listened to over 100 songs with it so far, and only found that one is had this problem. It is most likely less then 1% of songs that are incompatible with this device. For the price of this device it performs above and beyond. I recommend anyone that is looking for a wireless audio solution, and doesn't have a ton money buy it as soon as possible. It can be one of the coolest things on your computer or audio setup.

EDIT: I bought the proper antenna, and with it it reaches through the five walls and 1 block away.

Instructions

This is the part where you get to learn from my mistakes, and experiences. Before you even buy anything figure out what frequency you are going to be using because they ask you when at time of purchase. The best way to do this is to find some dead air. This was hard in my area because I live close to the San Francisco Bay Area, and there are a lot of radio stations. You can find the frequency by using a digital tuner. I didn't have a digital tuner available to me, and regular turn dial ones are not reliable. But I have thought of a way to determine a frequency using a turn dial. First find some dead air, then find the stations closest to the right and left of the FM dial. Listen to the stations until they say what there frequency is, and you should be able to use that to determine the frequency of the dead air. This is important more for the antenna then the actual transmitter, which can latter be tuned. Order the antenna when you order the transmitter. It is my understanding that you should not operate a transmitter without an antenna, and if you live in the states shipping takes up to 2 weeks. You can make one, but it will most likely cost you around the same amount as what they charge. When you buy an antenna from them they tune it, I believe this is done by cutting it to a certain length, to the frequency that you tell them, for optimal performance.

Once you have the transmitter you will need a 12volt power supply. You can use a 12volt battery or a 12volt adapter that you may have lying around. Radio Shack also sells them for around $10. Just make sure its 12volts. The voltage is always stated on the back. Once you have one you need to determine what the polarity of the wires are. I used a car battery tester that can be bought at any auto parts store. You can also use an old computer case fan by connecting the red (positive) and black (negative) wires to the 12volt adapter. If the fan comes on you have it the right way, if it doesn't then switch the wires and it should come on. Then connect it to the transmitter using wire nuts or butt splices.



You will also need something to receive the signal. If you don't already have something my suggestion is to get a cheap radio, like the one I got at Walmart for $5, and connect it to a set of 2.1 speakers. Creative Labs makes a great set that can be found on sale from time to time. I have found them as low as $20 after rebates. My Sunday Ad Links list may help you find some.

Other FM transmitters

If you have the cash to spend this is a good one to get for your computer because its actually a PCI card.
PCI MAX 2006+ PLL Stereo FM transmitter

Here is a list of links that I found
Link List

Here is a list of stuff I found on ebay
ebay

Something fun to use a FM transmitter for
http://www.mobmov.org/
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 Very useful informationon high power fm transmitters,  It amazes me that you would actually have that removed from your site.

 

 high power fm transmitter 

 

Thank You

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Sounds cool.

"Never trust a computer you can't throw out a window."

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Unless I missed something, I can't seem to find out who sells this transmitter.  I am very interested in purchasing it.  Would you mind telling me who sells it?

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realneil replied on Mon, Oct 12 2009 9:29 PM

www.wholehousetransmitter.com

Sells the unit that I use in my home. it works in stereo too. I have it connected to a music server running 24/7 and it works for the whole house.

You set your own frequency to transmit on so you don't interfere with real radio stations.

My neighbor just told me about the new blues station and gave me the freq I'm broadcasting to. He said, "there's NO COMMERCIALS!" Smile

Dogs are great judges of character, and if your dog doesn't like somebody being around, you shouldn't trust them.

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