Sunday, November 21, 2010

CZH-05B 500mW FM transmitter

I like to listen to the VK2WI Sunday broadcast. It's part of my weekly routine. This week I was able to listen to it lying in a hammock thanks to a new arrival, a small FM transmitter purchased on eBay.

Front.jpg

It's synthesised for frequency stability. At 500mW it saturates the house but doesn't go much past the neighbours. On the back there is a BNC connector and it comes with a little antenna. No doubt an external antenna would extend the range.

Internally, construction is of a very high standard:

Internal.jpg

It came with an over the top switched giant power supply. There is some hum evident in the signal but no doubt that could be improved with a regulated supply.

Over the years I've built many little FM transmitters but they always drift to some extent. It's nice to have something stable like this.

I think there could be a market for a radio station that broadcasts selected podcasts, my latest discovery is The Changelog. Now I can just make my own.

8 comments:

  1. I have recently received the CZH-05B and for "Audio" input it works great. My question is how to use the "Mike" input correctly. I bought and tested a microphone, but cannot get it to work on the CZH-05B "Mike" input socket. When I connect the "Mike" input to an audio source it barely comes through, but with lots of static and crackle. Could I have inadvertently damage the "Mike" input by feeding into it an audio source???? Rob

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  2. Anonymous2:56 AM

    when I ordered it I was really. skeptical but it sounds very good.
    The Audio input works great but is very sensitive: a careful setup of input level is required.
    I also tested the Mic input (unuseful for my purposes) but... believe me... forget it.
    with the short antenna I receive receive the audio up to 1 km. For sure better results with an external antenna.

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  3. I bought one of these specifically for the mic input, with the intention of using it in my van when I give tours. When I plugged in a mic I get absolutely nothing. Has anyone gotten the mic input to work at all?

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  4. I bought one of these specifically to use with a microphone, but I can't get the mic input to work. Has anyone had any luck with this?

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  5. I've only used the line input but I'll try the mic and let you know.

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  6. Lighthouser,

    I tried it out and the mic input does work - but not very well (at least with the mic I tried).

    Two things might trip you up: First the socket is stereo and if your mic plug is mono it could be shorting one side to ground, second you might be using a PC mic which requires DC power (normally provided by a sound card). I don't think this unit provides that.

    Best wishes,

    Peter

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  7. Anonymous7:15 AM

    about 3 out of 100 the mic jack will work I got in side of them its
    not the jack it its in the board they make in the far east for about $3.00 and the U.S. dealer mark them
    up from $15.00 tp $100+
    If you buy the ST-7A 7 WATT OUTPUTT
    the mic jack work real good
    + you can turn the power up and down
    just hold the power button down
    and plug the power jack in and thin you will see low and high power

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  8. Anonymous6:54 AM

    The Mic input on the CZE-05B takes a "Computer" type that needs power from the unit to work.
    Shimples.

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