[Moved] FM TRANSMITTER with a distance of at least 1km

[rodzrods]

how to increase the range of an fm transmitter? my transmitter ranges only from 20-30 meters.. i need at least 1km.. thanks

 

[srizbf]

how to increase the range of an fm transmitter? my transmitter ranges only from 20-30 meters.. i need at least 1km.. thanks

trasmission reach depends on 1) output power and 2) height of the antenna above ground.

if yours is a bought one , then you may have to get incresed output power module , if it is modular.

increase in height alone to reach 1 km from 20 m is not feasible. depends on terrain and mountain ....

 

[BradtheRad]

This topic comes up occasionally. See the list of related threads at the bottom of this column.

Also try a search on 'fm transmitter'.

 

[davenn]

This topic comes up occasionally. See the list of related threads at the bottom of this column.

Also try a search on 'fm transmitter'.

agreed

and to the OP

be prepared to pay large type approval and licence fees if you want it to be legal
else risk the repercussions of fines etc if you are caught5 by the authorities in your country

Dave

 

[jiripolivka]

how to increase the range of an fm transmitter? my transmitter ranges only from 20-30 meters.. i need at least 1km.. thanks

a typical mistake of many tinkerers.
FM transmitter power is not the only quantity in a communication SYSTEM design.
To get a 1 km range, one MUST know:
- transmitter power,
-transmitting antenna gain and radiation pattern,
- receiver noise figure,
- receiving antenna gain and pattern.

For FM modulation, also RF frequency, modulation deviation.

Increasing only transmitting power twice can be costly while improving on antennas is low-cost and more profitable.

 

[rodzrods]

trasmission reach depends on 1) output power and 2) height of the antenna above ground.

if yours is a bought one , then you may have to get incresed output power module , if it is modular.

increase in height alone to reach 1 km from 20 m is not feasible. depends on terrain and mountain ....

I already have tried to increase the height of my antenna but it was still the same. I personally made the circuit, I just copied the schematic from the google.

 

[BradtheRad]

An old-timer emphasized the importance of tuning the antenna to match the output stage (or maybe it was output frequency).

He said that's how he could 'work the world' with his low power transmitter, while he noticed other hams had trouble getting a signal out even with several watts, due to mismatched impedances.

 

[Audioguru]

The sensitivity of the FM radio is very important for good range.
My FM transmitter has an 80cm piece of wire for its antenna. The transmitting and receiving antennas must be parallel. Its range is more than 2km across a wide river valley to my very sensitive car radio and home stereo tuner. Its range is about 200m down the street to my cheap Sony Walkman portable radio and cheap clock radio when there is nothing in between. Its range is across the street (30m?) to a cheap FM radio from The Dollar Store.

The FM transmitter probably will not work if it is built on a solderless breadboard because good RF wiring practice must be used for low capacitance between parts and a compact layout with very short wires for low inductance.

How can we tell you how to increase the range of your FM transmitter when you did not even post its schematic, parts list and photo?