Some More Simple FM Transmitters

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audioguru said:
The tuned circuits and the amplitude of the modulation determine the bandwidth, not the wire gauge of the antenna.
Click to expand...
What I meant by bandwidth is the precision of the tuneable range ie 108Mhz to say 110 Mhz. for fine wire as opposed to sau 106Mhz to 113Mhz for thicker wire . See what I am asking?

I take it you are probably not a radio ham?
Wire cross -section is quite a factor at HF. The cross section of the driven element can change the sharpness of bandwidth of a beam antenna by as much as 30%.
 
I know that very high frequency RF travels on the surface of a conductor and if it is thicker then it has a larger surface and therefore its RF resistance is less.
You mention "driven element" and "beam antenna". We were talking about just a single whip antenna. I used 22AWG wire.
 

Pardon me- A person of like AudioGURU, with his exposure to electronics and RF engineering, need not, I fear, be a radioHAM to be able to answer me or us in the field of RF.

In technical society, there are eminent persons in in RF and AudioGURU is no less. . RadioHAM is only a practical experimentation of RF theory.
 
I have made only two transmitters in my life. They were both FM transmitters.
The first one was from a magazine.
The second one was when I fixed then improved a defective one and copied things from others.

An RF expert on another website boosted the output power of my transmitter 10 times and reduced its harmonics by adding many parts. I don't want more output and I don't want more parts.
 
Fair enough mate.
I just wanted to see if you had tried . I might do so and I fear you will be pretty right anyway. I will not be able to discern any appreciable difference.
Same applies to verticals and horizontal antennas of all kinds- people using dipoles get the same effect with smaller diameter wire.
Thanks
 
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dear audioguru

i have builed many sort rang transmetere but i have no idea how can i increas range of transmeters suppose i want 5km range of thansmeters than what i do for this. so pl send us suggestion for this.
 
One question...

Hi,

One question has always been with me...

I can get a resistor , can get a capacitor of a certain value...

Can we get an inductor of 0.1 uH as shown in first picture..

Regards,

Simran..
 
simrantogether said:
Hi,

One question has always been with me...

I can get a resistor , can get a capacitor of a certain value...

Can we get an inductor of 0.1 uH as shown in first picture..
.
Click to expand...

You 'could', but it would be a pointless exercise, paying good money for a few turns of wire round a pencil!.Toko make such coils.
 
anilgupta said:
dear audioguru

i have builed many sort rang transmetere but i have no idea how can i increas range of transmeters suppose i want 5km range of thansmeters than what i do for this. so pl send us suggestion for this.
Click to expand...
Why take the risk of being caught by cops and move around courts stopping your education or job, Sir?
 
If you transmit a powerful FM signal then its harmonics will cause TV interference to many people. Then you will be in trouble.

It will be easy for the RF cops to find you. Then they shoot you and chop off your head.
 
A cheap walkie talkie is a child's toy. its range is only 100m.

Good tranceivers are made, are inexpensive and have a range of 13km and more. You won't find the parts to make them and won't be able to design and align the complicated circuit.
 

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Hi,

If you are looking for more ideas about building FM transmitters, look here:

https://pira.cz/eng/

PiRa = Pirate Radio

I haven't built any transmitter from that site but I believe it would work - just be careful that operating such transmitters can be illegal ...

There is a description on that site of a very simple frequency counter which I have built a few years ago and it works very well so I believe the transmitters would work as well.

Petr
 
What kind of board is your circuit assembled on? I have never seen one like that. Is it soldered or wire wrapped? It looks really cool.
 
locust said:
What kind of board is your circuit assembled on? I have never seen one like that. Is it soldered or wire wrapped? It looks really cool.
Click to expand...
My FM transmitter is made on Stripboard. It is perforated and has parallel copper strips. The copper strips are cut at a hole then the remainder of the strip is used for another part of the circuit. The strips make half a pcb and the parts and a few jumper wires make the remainder of the pcb. Each hole has a single wire in it.
 

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