FM transmitter (mod4)

[Hero999]

Don't forget that it's a squaare law so to double the distance you need quadruple the power.

You could try a high gain aerial on both the transmitter and receiver which will boost the range in one direction only.

 

[MALLI]

i want to build this fm transmitter please help me how long it can transmit

 

[MALLI]

what is maximum distance that no need to take licience

 

[MALLI]

please send working & circuit diagram of this fm transmitter

 

[Hero999]

Use the EDIT button, it looks like this:

The distance this transmitter can cover depends on how sensitive the receiver is and if there any objects obscuring the path.

We don't know what the laws are in your country because you haven't filled your location in.

Look at the start of the thread for schematic of this transmitter.

 

[sang_fajar]

thanks dude

 

[Rippey574]

Whats the bandwidth on this transmitter? What would it take for me to adapt it to 2M?

 

[audioguru]

Whats the bandwidth on this transmitter? What would it take for me to adapt it to 2M?

My Mod4 FM transmitter is wideband on the FM broadcast band.
The 2m band has audio that is narrowband and sounds awful like a telephone.

 

[Rippey574]

My Mod4 FM transmitter is wideband on the FM broadcast band.
The 2m band has audio that is narrowband and sounds awful like a telephone.

I does the fm follow the standard of 200kHz band with? If you have a good transmitter you can adjust the bandwidth for 2 meter, I heard some people claim they are on 300kHz bandwidth on 2 meter.

 

[JimB]

Whats the bandwidth on this transmitter?

Far too wide.
It is designed as a kiddy toy to play music in the FM broadcast band.
You can however turn down the deviation by reducing the amplitude to the audio.

What would it take for me to adapt it to 2M?

Just need to reduce the number of turns on the coil.
However, other than a learning exercise on the bench, dont bother!
All you will find is that it is totally unsuited to narrow band operation, it will drift off frequency as soon as you look at it, and if you touch it, woh!! it will scoot half way up the band.

JimB

PS dont worry about AGs comments about poor audio quality on 2 metres, he has a HiFi fixation, fo him all audio systems must have a flat frequency response from DC to daylight.

 

[audioguru]

PS dont worry about AGs comments about poor audio quality on 2 metres, he has a HiFi fixation, fo him all audio systems must have a flat frequency response from DC to daylight.

I normally hear from 20Hz to 20kHz and narrow-band does not sound the same. The important sounds in speech (consonants) are well above 3kHz.
Didn't you hear the "ducks quacking" on the SSB radio recordings on a thread here?

My son recently got an i-phone with all the bells and whistles. But it transmits extremely distorted square-waves and is very hard to understand what is said.

 

[JimB]

I normally hear from 20Hz to 20kHz

I believe that you are 60+ years old, in which case your hearing is exceptional.
When I was 20 I could hear 18kHz, I could still hear 18kHz when I was in my mid 30s.
Now I am 59 and at the last hearing test I had (1 year ago) the best I could do was 5.5kHz.

Didn't you hear the "ducks quacking" on the SSB radio recordings on a thread here?

I listen to SSB on the air every other day, have done for the past 40 odd years, sometimes it helps the intelligibility of a signal swamped with noise to adjust the pitch to be slightly higher than normal.

Just give it a rest mister golden ears, not all sounds need to be full hifi, 300 to 3000 hz is good enough for most speech provided it is not all distorted to hell with overdriven super miniature speakers (i-phone?).

JimB

 

[audioguru]

When I was 20 I could hear the "ultrasonic" motion detector at the museum. It played 24/7 because it was "not audible". It was deafening.
No, I am not a girl and am not a dog. Instead I am a dirty old man.
I can still hear some CRT TVs whistling at 15.7kHz.

I could hear that the new speakers at the concert hall and stadium sounded bad.
I could hear huge differences between different tweeters.
I have never had my hearing tested because they don't test higher than only 8kHz.

 

[srinivaas ganesan]

hi.. can anyone reccomend me a good book for communication systems...
is simon haykin good... i d like to learn a lot about communications and networks... wat are the good self study books..

 

[mvs sarma]

hi.. can anyone reccomend me a good book for communication systems...
is simon haykin good... i d like to learn a lot about communications and networks... wat are the good self study books..

Kennedy is a known good book on Communication systems Ganesan.

Here is a link
**broken link removed**

the book approximately costs Rs310/-

 

[mvs sarma]

When I was 20 I could hear the "ultrasonic" motion detector at the museum. It played 24/7 because it was "not audible". It was deafening.
No, I am not a girl and am not a dog. Instead I am a dirty old man.
I can still hear some CRT TVs whistling at 15.7kHz.

I could hear that the new speakers at the concert hall and stadium sounded bad.
I could hear huge differences between different tweeters.
I have never had my hearing tested because they don't test higher than only 8kHz.

better remove the word "old" as we still feel that you are younger in technical abilities & mindset compared to youngest. long live AG

 

[flat5]

AG, I played a gig this evening you would have left before you took your coat off. Some guy rented a room with speakers that were classic bad sound. No midrange and cheap piezo tweeters (much worse than even Motorola). They did not have a clue. No mid so they must have set the treble all the way up. Incredible distortion for 4 hours until I could get out of there. I did not bother to say anything to the people in charge. I know better.
A band member did and told me I was right. They just got upset.
However, the whiskey was free and I did not have to drive!
Sometimes in situations like this or worse I put toilet paper in my ears but tonight I did not think of it. Weird...

 

[srinivaas ganesan]

can anyone tell me hoe to do a technical paper.......
what s expected from engineering students,...
and what brings the winning strategy...

 

[srinivaas ganesan]

thank you mvs sarma... does the book start from the very basics...
is it good for self study....

 

[hussam]

its a useful thing