Simple & Powerful FM Transmitter(only one transistor)

[ajex]

Its very simple one and powerful, working in 5Km radius circular range..

https://sites.google.com/site/ehobbyprojects

 

[vfone]

Re: Simple & Powerful FM Transmitter(only one transistor

2SC1162 is an Audio Frequency power transistor. Hard to believe that will oscillate at 100MHz FM broadcast band.

 

[betwixt]

Re: Simple & Powerful FM Transmitter(only one transistor

Please don't use it within 5Km of me!
It has no frequency stabilization whatsoever, it will drift frequency as the battery discharges, it is both AM and FM and I would guess it produces as much of its output in harmonics as in the fundamental frequency. There is no RF filtering or decoupling on the supply or input connections and it will shift frequency as objects or people move close to the antenna.

Brian.

 

[FvM]

Re: Simple & Powerful FM Transmitter(only one transistor

"They're Coming To Take Me Away, Ha-haaa." (from a pop song)

 

[betwixt]

Re: Simple & Powerful FM Transmitter(only one transistor

Now you are showing your age!

Brian (sadly, I remember it too!)

 

[ajex]

Re: Simple & Powerful FM Transmitter(only one transistor

Please don't use it within 5Km of me!
It has no frequency stabilization whatsoever, it will drift frequency as the battery discharges, it is both AM and FM and I would guess it produces as much of its output in harmonics as in the fundamental frequency. There is no RF filtering or decoupling on the supply or input connections and it will shift frequency as objects or people move close to the antenna.

Brian.

yes ur correct Brain. Its not a stable one. But it would be helpful for beginners to get some experience.

Added after 4 minutes:

Now you are showing your age!

Brian (sadly, I remember it too!)

Brother all we r not in the same age. but sometimes I'll be pass ur age..!

 

[ajex]

Re: Simple & Powerful FM Transmitter(only one transistor

2SC1162 is an Audio Frequency power transistor. Hard to believe that will oscillate at 100MHz FM broadcast band.

Sure, its a Audio frequency power transistor. but it can oscillate up to 180Mhz..

 

[flatulent]

Re: Simple & Powerful FM Transmitter(only one transistor

I will show my age. The triode audio amplifier valves used decades ago would work to 100 MC/s.

 

[Audioguru]

Why do NOOBs make garbage circuits?

 

[vfone]

Re: Simple & Powerful FM Transmitter(only one transistor

When Lee de Forest invented the “Audion” triode in 1908 the maximum frequencies used for radio communications were medium waves, not even short waves.

The parasitic internal capacitance's in audio tubes are much lower than internal capacitance's of audio power BJTs.

Audio pentodes which have much lower capacitance than triodes (due to the screening of the additional grid) can be used to amplify signals up to 50MHz, but not higher than this.

 

[betwixt]

Re: Simple & Powerful FM Transmitter(only one transistor

Don't they just.

I get a sense of using Edaboard that there are four distinct types of user:

1. Ones who have learned the hard way but are now proficient and aware of the pitfalls in this industry. Without boasting, I would put myself in this category.

2. Ones with enthusiasm and inquiring minds who genuinely want to learn. These are the ones who will make something of their lives.

3. Freeloaders who post scans of their homework and complain bitterly when nobody does it for them. These people should be discouraged, if that's the best they can do they will never stand on their own feet.

4. An 'unclassifiable' group of people who are just non-starters. The ones who haven't a clue what they want to do or how to do it but they have a hair-brained idea that they think SHOULD work and persist in extolling the virtues of the impossible. You know the ones: "I've got this great idea for harnessing lightning and storing it watch batteries so I can generate three phase PWM with a Z80 and use it to flash an LED - can someone post schematics"

Going back to the original topic - I have equipment here which can sniff nanovolt signals from DC to tens of GHz, the thought of someone nearby with a transmitter firing several Watts of square waves into the spectrum really horrifies me.

Brian.

 

[zlatkoMM]

Re: Simple & Powerful FM Transmitter(only one transistor

Like always Audiguru is a smart ass....
Garbage project- how you can say that someone work is garbage?
This is just beginner project so if work ....ok for me.

 

[Audioguru]

Re: Simple & Powerful FM Transmitter(only one transistor

Like always Audiguru is a smart ass....
Garbage project- how you can say that someone work is garbage?
This is just beginner project so if work ....ok for me.

Its frequency will drift all over the place if something moves toward or away from its antenna and as the battery runs down.
It will sound awful without treble frequencies.

It will cause frustration to the beginner because it doesn't work properly.

 

[betwixt]

Re: Simple & Powerful FM Transmitter(only one transistor

I have to side with Audioguru here.

Yes, it is a simple project and a beginner could easily build it, but equally, it is a very bad example of electronic design and highly polluting to the radio spectrum.

Surely, teaching someone bad practice and making them unpopular with the rest of the neighborhood is to be discouraged.

Brian.

 

[zlatkoMM]

Re: Simple & Powerful FM Transmitter(only one transistor

You can hold em something else if you wish.
Of course that this simple circuit is not perfect.

 

[amjadali56]

try this one ! and u can replace th e 2C1971 with 2C1972 for a larger area.

 

[pranam77]

Re: Simple & Powerful FM Transmitter(only one transistor

try this one ! and u can replace th e 2C1971 with 2C1972 for a larger area.

The given schematic is of a Rf amplifier whereas the discussion here is about a simple FM transmitter. There are ample good FM transmitter circuits on the web with one coil or with coil printed on the PCB. Guess such designs are ideally suited for newbies..

 

[ajex]

Re: Simple & Powerful FM Transmitter(only one transistor

try this one ! and u can replace th e 2C1971 with 2C1972 for a larger area.

oh..... this is not a FM tarnsmitter. this is a RF amplifier.. We r discuss abt a FM transmitter here..

 

[ajex]

Re: Simple & Powerful FM Transmitter(only one transistor

Its very simple one and powerful, working in 5Km radius circular range..

https://sites.google.com/site/ehobbyprojects

Finaly I want to tell something. I tried to make a powerfull FM transmitter before 2yrs, I collected lot of circuits and try to build its and couldn't make a working one.<I think these r little advance> But after that I found a simple one from a book and 1st time i'm able to make a transmitter to transmit FM signals to more distance. This is the circuit that I build. Just think sometimes if I didn't try to build garbage circuit <This is not my word, actually I dn't like to tell that> like this, i'm unable to get experience with a FM transmitter.. there is a elegant thing in every garbage..! :|

<sorry for my bad English>

 

[betwixt]

Re: Simple & Powerful FM Transmitter(only one transistor

Ajex, the point we are making is this is not a good schematic and it will cause interference to other people. The signal it produces is not 'clean' and it is not stable. How would you feel if nearby emergency services could not use their radio links or telephones because someone used this schematic, maybe it was you that needed the emergency services.

For a few components more, a MUCH better transmitter can be made that will not cause interference, give better audio and have a predictable frequency. Before you ask, I have qualifications, a certificate and license to use radio transmitters and I do so between 125KHz and 10.4GHz so I appreciate the complications of radio transmissions. Unless you also have a license to transmit, I will not help you build equipment of this kind.

Brian.