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How can RF cops find you? Is there any special tool for it like Tracker transmitter?
You don't understand that most transistors have the same voltage gain. The old 2N3866 is in an old metal case so a clipped-on heatsink can keep it cool. Since it has the same voltage gain as a tiny 2N3904 transistor then for more output power its needs more input power. It needs a driver transistor to provide it with more input power.hi audioguru
i powered ur transmitter circuit using a 3.7v mobilephone battery so how much k-ohm can be the value of biasing resistor of 2n3866? A nokia 3.7v battery has high current so it will work perfectly
My FM transmitter is fairly low power so a BC547 will work the same as my 2N3904.
"How many long it could be reach" does not make sense in English. Maybe you are asking how far away it can be received which we call "its range"?
I tested it across a large river valley with nothing in between. It was more than 2km to my expensive very sensitive FM stereo and my very sensitive car radio, it was about 300m to a cheap portable Sony Walkman FM stereo radio and it was across the street to a cheap FM radio from The Dollar Store (it uses a TDA7088 FM radio IC). The Dollar Store sells very cheap Chinese and Indian junk). In my neighbourhood houses and trees reduced the range a lot.
The transmitter antenna was 80cm long and hanged vertically out an upstairs window. My FM stereo and car radio antennas were also long and arranged vertically. My Sony Walkman radio uses its earphones cord as the antenna (not good) and the radio from The Dollar Store has a whip antenna that is much too short at about only 12cm (it picks up only strong local stations but is also overloaded by many of them).
Many cheap FM radios are overloaded by strong local stations so the range will be reduced a lot. My cheap Sony Walkman radio has a local-distant switch that attenuates the antenna input when switched to local. When overloaded a station appears at many points across the dial.
When my transmitter is close to a cheap radio then it appears at many points across the entire dial.
This is my FM transmitter circuit. I built it on stripboard and I cut the strips with a drill bit. The strips form half of a pcb.
1mm wire is thick. It might be 14SWG. They have 9 turns. It has enamel insulation.Dear guru,
Is L1 and L2 by 10 turn of 1mm wire on 3mm former in your this FM? Is 1mm means 20 SWG?
The RF amplifier separates the oscillator from the antenna so things moving toward and away from the antenna do not change the oscillator's frequency.1) Oscillator and RF amplifier separated circuit (like your) gives more RF power and long range too?
A buffer will not work unless the supply voltage is increased and a higher power RF amplifier transistor is used.2) Is it possible to make different another RF buffer stage using 3904 for great range? Please guru, design or show me a circuit like this.
The Chinese datasheets give no spec's for use at VHF radio frequencies.3) I heard that S8050 gives more RF output power better than 3904, is it true?
The Chinese datasheets give no spec's for use at VHF radio frequencies.
Weitron in Taiwan make an S8050 NPN transistor. Wing Shing in China make an S8050 PNP transistor. Which one is correct?
Use a S8050 NPN transistor made by Weitron of Taiwan. I think Wing Shing of China has a translation problem with their datasheet.I think that is s8050 is NPN. Please check this FM transmitter circuit of s8050
https://ziddique.wordpress.com/2011/12/28/simplest-fm-transmitter/
Can it transmit more than 1km? Is it reliable circuit? Please check the circuit and tell me true please! Is both s8050 PNP and NPN in same size? How to know which is NPN?
This is my FM transmitter circuit. I built it on stripboard and I cut the strips with a drill bit. The strips form half of a pcb.
This is my FM transmitter circuit. I built it on stripboard and I cut the strips with a drill bit. The strips form half of a pcb.
It is the LM2931A 5.0 which is a 5V low-dropout voltage regulator in the same small plastic case as the transistors. There are many 5V low-dropout voltage regulators available today.1) in your circuit diagram, there are 3 transistor but in real built transmitter figure, there are 4 transistors and other additional devices. What is that? Which is this another one transistor?
I wound them on a 3mm diameter drill bit.3) are L1 and L2 in 3 mm former?
Can you solder to aluminum? I can't.4) Can i wind aluminium insulated wire instead of copper wire?
My wire is solid copper wire that is stiff and stays coiled. Maybe you are using stranded wire that is flexible.5) How to wind coil correctly? When i wind coil, it stretches immediately.
You did not post your detailed schematic so we cannot calculate its maximum collector current.ASKING TO YOU AGAIN:
I've built a Fm transmitter
using single transistor
bf494. If i powered it with
12v, 45 amp. battery, will
my transmitter damage
due to high ampere or
not??