Low cost, low power FM transmitter to send audio to stereo?

[Joerg]

Hi Folks,

Is there any low cost FM transmitter or modulator I could use to send
audio from a shortwave receiver, PC or whatever to the stereo in another
room? A low power transmitter would be best since that could also be
heard on other radios in the house. I am thinking about something under
$50, with PLL to select a free FM frequency. And FCC compliant, of course.

Reason I ask: X10 has xmit/rec pairs that do this for about $60 but
these only transmit audio to one destination and you have to use a box
with power supply and all at the receiving end. Not so good for a
portable radio, especially those without line-in jacks. Radio Shack
didn't have anything which surprised me since that is where I bought a
nice UHF modulator for around $40. That one has a PLL which can be set
to any channel and is very stable. No complaints regarding image quality
and audio, works like a champ. I figured there ought to be something
that does the same for the stereo and isn't more expensive.

Regards, Joerg

 

[Jem Berkes]

Is there any low cost FM transmitter or modulator I could use to send

audio from a shortwave receiver, PC or whatever to the stereo in
another room? A low power transmitter would be best since that could
also be heard on other radios in the house. I am thinking about
something under $50, with PLL to select a free FM frequency. And FCC
compliant, of course.

I have an old kit from Radioshack that does this, and I think it cost $20
back in 1995, don't know if it still exists. Max range was about 50 m.

FM Wireless Mike
Radio Shack Cat. No. 28-4030

The kit included the PCB and parts. It uses an electret condensor mic.
Variable coil for tuning; nothing fancy. Works surprisingly well

 

[Joerg]

Hi Jem,

Seems they discontinued that. But there is another problem with it: The
frequency isn't very stable on those, it is no PLL but is tuned in via
either a coil or variable capacitor. That drifts quite a bit. Most of
the modulators to bring audio onto a car radio are the same, when it
gets hot their frequency runs away.

Regards, Joerg

 

[TC]

What about the little transmitters now available to send your portable MP3
player output to your car FM radio?

 

[Joerg]

What about the little transmitters now available to send your portable MP3
player output to your car FM radio?

Well, the ones I have seen are free running simple oscillators and that
is not very stable. If you have come across one where the frequency can
be programmed please let me and this news group know.

Regards, Joerg

 

[Joerg]

Hi TC,

What about the little transmitters now available to send your portable MP3
player output to your car FM radio?

After some searching I found one that has a PLL, offering four frequencies: Thge Irock from www.myirock.com

As long as one of the frequencies isn't occupied that might do. But they only state 10-30 feet range. That ain't a whole lot and won't work between rooms too well.

Regards, Joerg

 

[Bill Bailley]

Hi Folks,

Is there any low cost FM transmitter or modulator I could use to send
audio from a shortwave receiver, PC or whatever to the stereo in another
room? A low power transmitter would be best since that could also be
heard on other radios in the house. I am thinking about something under
$50, with PLL to select a free FM frequency. And FCC compliant, of course.

You need a mate in Australia. Built two. Work great.

Micromitter Stereo FM Transmitter Kit

STOCK-CODE: KC5341

http://www1.jaycar.com.au/


Bill.

 

[Wouter van Ooijen]

Is there any low cost FM transmitter or modulator I could use to send

audio from a shortwave receiver, PC or whatever to the stereo in another
room? A low power transmitter would be best since that could also be
heard on other radios in the house. I am thinking about something under
$50, with PLL to select a free FM frequency. And FCC compliant, of course.

http://www.voti.nl/shop/p/K-DIY-32.html

to order: http://www.riccibitti.com/tinyplanet/tiny_intro.htm


Wouter van Ooijen

-- ------------------------------------
http://www.voti.nl
PICmicro chips, programmers, consulting

 

[Allan Herriman]

You need a mate in Australia. Built two. Work great.

Micromitter Stereo FM Transmitter Kit

STOCK-CODE: KC5341

http://www1.jaycar.com.au/

It uses a BH1417F from ROHM, and features a stereo modulator and a
PLL for the carrier.


Or roll your own using these parts:
http://www.rohm.com/products/shortform/06audio/3high.html#1e
(You will need a 7.600 MHz crystal.)

Regards,
Allan.

 

[mike]

It uses a BH1417F from ROHM, and features a stereo modulator and a
PLL for the carrier.


Or roll your own using these parts:
http://www.rohm.com/products/shortform/06audio/3high.html#1e
(You will need a 7.600 MHz crystal.)

Regards,
Allan.

You can buy these things all over.
Sometimes marketed as devices to play your walkman in thru the car
radio.
BUT!! They're low power and depending on where you live, there may
not be any clear channels wide enough for range more than a foot.

Does it have to be the stereo? Baby monitors work great for this
application.
mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[Joerg]

Hi Bill,

There isn't much detailed info on the Jaycar site. They do ship int'l
though but state that it must be airmail which gets expensive. Thanks
for the hint, I'll look if someone in the US makes a transmitter like
this. No problem to build my own but if I can buy one that would be less
work.

Regards, Joerg

 

[Joerg]

Hi Wouter,

That's not a PLL solution. When you live in California where it can be
anywhere from -5C to +45C free running oscillators can drift more than
Camembert cheese.

Regards, Joerg

 

[Guy Macon]

Get a copy of Nuts and Volts magazine. There are several ads in every
issue for what you are looking for, and it's a magazine you should be
reading given your interests

 

[Joerg]

Hi Guy,

When I get into town I'll pick one up. We live in the country and
magazines like that are hard to come by around here. But, you can get
everything about trucks, horses, ranching etc.

Anyway, I checked Nuts and Volt's advertisers index on RF transmitters
and it came up with only three companies. Abacom, Lemos and Matco. It's
all the usual WLAN and ISM datacom stuff, no FM band gear.

Regards, Joerg

 

[Mark Zenier]

Well, the ones I have seen are free running simple oscillators and that
is not very stable. If you have come across one where the frequency can
be programmed please let me and this news group know.

Ramsey has a kit with a synthesized frequency control but it's in
the $150 price range.

Mark Zenier [email protected] Washington State resident

 

[Tweetldee]

Hi Guy,

When I get into town I'll pick one up. We live in the country and
magazines like that are hard to come by around here. But, you can get
everything about trucks, horses, ranching etc.

Anyway, I checked Nuts and Volt's advertisers index on RF transmitters
and it came up with only three companies. Abacom, Lemos and Matco. It's
all the usual WLAN and ISM datacom stuff, no FM band gear.

Regards, Joerg

Why wait until you go into town? Go to http://www.nutsvolts.com and click
on the Advertiser Links. Most of the advertisers that have web sites are
there, ready for you to surf.

--
Dave M
MasonDG44 at comcast dot net (Just subsitute the appropriate characters in
the address)

Never take a laxative and a sleeping pill at the same time!!

 

[Joerg]

Well, that's exactly what I did. Came up with the three I mentioned. All
WLAN and ISM stuff.

Regards, Joerg