tag:blogger.com,1999:blog-14285638534500245712024-03-05T02:07:47.095-08:00FM Transmitter Circuit Diagram & Project Kitsimonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.comBlogger10125tag:blogger.com,1999:blog-1428563853450024571.post-6564045432839020642011-06-26T23:31:00.000-07:002011-06-26T23:36:10.555-07:00Build very low cost FM transmitter, use your TV antenna and transmit upto 4km range!!<span style="font-size: large;"> </span><span style="color: green; font-family: Arial,Helvetica; font-size: large;"><b><u>Here is the specification of the transmitter</u>: </b></span><br />
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<div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: small;">1. No. of stage: 4</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: small;">2. Frequency of operation: About 100MHz</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: small;">3. Antenna type: Folded 300 ohms dipole.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: small;">4. Range obtained in free space: Up to 4km with dipole antenna 30 feet above ground level. More range with yagi antenna.</span></div><div align="left"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEga-hFAs_r9Cv_20K9tZ63ZweNvPs33uH3yjV94uW0T4Bb97kCTz9c1AQ0bvZ8-rHrsDUj5-n7QcBFfNJnVyvmPf5WLbwKShLxXAif-NbzLGkoZQRZTBkVlmDg0HJ9MEi5VqLjtuLRSEXE/s1600/2kmtx_ckt.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="102" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEga-hFAs_r9Cv_20K9tZ63ZweNvPs33uH3yjV94uW0T4Bb97kCTz9c1AQ0bvZ8-rHrsDUj5-n7QcBFfNJnVyvmPf5WLbwKShLxXAif-NbzLGkoZQRZTBkVlmDg0HJ9MEi5VqLjtuLRSEXE/s320/2kmtx_ckt.gif" width="320" /></a></div><div style="text-align: center;"><span style="color: red; font-family: Arial,Helvetica; font-size: small;"><b>Fig: </b></span><span style="color: red; font-family: Arial,Helvetica; font-size: small;"><b>Circuit diagram of the Transmitter</b></span></div><div style="text-align: center;"><br />
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</div><div align="left"><span style="color: magenta; font-family: Arial,Helvetica; font-size: large;"><b><u>Brief Description:</u></b></span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">The transmitter is built on a Printed Circuit Board. This board uses track inductor for L1, L2 and part of L3. The section built around Q1 is the oscillator section. Oscillation frequency is determined by L1, C4 & C5 which forms the tank. Actually C5 is the feedback capacitor. This is required to sustain oscillation. This also influence the operation of tank formed by L1 & C4. Modulation is directly applied to the base of Q1 via C2. A microphone is connected here to serve this purpose. You can alternately feed direct audio here after disconnecting the microphone biasing resistor R1. Q2, Q3 & Q4 gradually raises the output power up to the desired level.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">As most of the inductors are PCB etched, there is practically very little frequency drift provided you use a highly regulated and ripple free power supply.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">RF output from the transmitter is taken from the junction of C11 & C12. This is unbalanced output of around 75 ohms impedance. But a folded dipole is a balanced type antenna of around 300 ohms impedance. So we need to use a 'BALanced to UNbalanced transformer' or 'BALUN'. A 1:4 type BALUN is employed here for this purpose. Antenna connection is taken from this BALUN via a 300 ohms flat parallel feeder cable commonly used in television to receive terrestrial broadcast. No coaxia is used to feed antenna. This saves cost. Also a parallel feeder cable provides much less signal loss compared to a coaxial.</span></div><div align="left"><br />
</div><div style="text-align: center;"><div style="text-align: center;"><span style="color: red; font-family: Arial,Helvetica; font-size: small;"><b> <span style="background-color: blue; color: yellow;">Click 'Read More" to see details with pictures</span></b></span></div><span style="color: red; font-family: Arial,Helvetica; font-size: small;"><b></b></span></div><div style="text-align: left;"><span style="color: red; font-family: Arial,Helvetica; font-size: small;"><b><a name='more'></a></b></span></div><div style="text-align: left;"><br />
</div><span style="color: magenta; font-family: Arial,Helvetica; font-size: large;"><b><u>Design of BALUN</u></b></span> <br />
<span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">The BALUN is made using a two-hole binocular ferrite bead as shown above. You need to use parallel insulated twin wire to construct this. This wire is commonly used to wind TV BALUN transformer. If you want to get rid of this, then buy a ready-made TV BALUN that is generally used at the back of your television set for interfacing with feeder wire.</span> <br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5HjYfEOpTSerln7x0wztDjAKsf8KrcK9B-0pGyrKQbDJMKcRPhA3y5E2ovmUdtAICq-zxek_5x5wavCSEvdXAB2tBet_IBJsZ53HrT_vlfMkNQPV3G3GYC2SCJNtGbQPdex19IRGDrJ0/s1600/Bal_cir.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5HjYfEOpTSerln7x0wztDjAKsf8KrcK9B-0pGyrKQbDJMKcRPhA3y5E2ovmUdtAICq-zxek_5x5wavCSEvdXAB2tBet_IBJsZ53HrT_vlfMkNQPV3G3GYC2SCJNtGbQPdex19IRGDrJ0/s1600/Bal_cir.gif" /></a></div><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">If you prefer to build this yourself, the circuit diagram is given above. You need to carefully construct it keeping in mind about the 'sense' & 'direction' of turns. See there are four coils. Two coils in the upper section, which are red and blue, required to be wound on left side of the BALUN and the remaining two (blue & red) in the lower half to be wound on right side. Connection marked 'A' and 'B' at the left side of the circuit is reqired to be connected to the PCB at the shown point. As dipole antenna is balanced type, so you need not to worry about its connection.</span> <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMpjU8NrH1pXxW3_22mpD8FSgPzM99RF8SAB3U-0tzNNYr78-MCxLIxBQ2S7tcXNIzGNdNV1J221fwQ9sCnIVJ5W_kU_dQghV_6IfZYZg6E_lKtnDO3i35f2kuQh9GmqNBengRkEx1_ms/s1600/balun.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgMpjU8NrH1pXxW3_22mpD8FSgPzM99RF8SAB3U-0tzNNYr78-MCxLIxBQ2S7tcXNIzGNdNV1J221fwQ9sCnIVJ5W_kU_dQghV_6IfZYZg6E_lKtnDO3i35f2kuQh9GmqNBengRkEx1_ms/s1600/balun.gif" /></a></div><br />
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<span style="font-size: large;"> </span><span style="color: magenta; font-family: Arial,Helvetica; font-size: large;"><b><u>PCB design details</u></b></span><br />
<span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">The transmitter is built on a single sided PCB. As mentioned earlier, this PCB has a number of etched inductors. For this reason, you need to very carefully construct the PCB as mentioned below.</span><span style="color: magenta; font-family: Arial,Helvetica; font-size: x-small;"><b><u> </u></b></span><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsXM1_kETdjRSV-6Tm69ERPVlCtp-O5rwyRrR7ctmTWLeYLj7TahgbGv63JOgFXv4FX3ILTD1YrZ7srRSl0HHKVa-zHmG0u08i1xvuzVsFgTKn_E5ZUcM2ewd_ZZqrdrmX2Ld-245CRKM/s1600/2kmtx_pcb.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsXM1_kETdjRSV-6Tm69ERPVlCtp-O5rwyRrR7ctmTWLeYLj7TahgbGv63JOgFXv4FX3ILTD1YrZ7srRSl0HHKVa-zHmG0u08i1xvuzVsFgTKn_E5ZUcM2ewd_ZZqrdrmX2Ld-245CRKM/s1600/2kmtx_pcb.gif" /></a></div><br />
<span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">The above drawing is the copper side and below shown is the component mounting plan.</span> <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXtqM1RZDBrpu_Gu0_cOfoeXqQVWoOdErgZ8In5e3688nZstTZuUDtrx8LFK2vxCc6ovEqSUT0PuIXLP6ezrSXrJRKhY93k0v8lIuBQRQtNCAq9DvF1sr35iRDf1BI1foiW7dB5ow7rAo/s1600/2kmtx_lgd.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXtqM1RZDBrpu_Gu0_cOfoeXqQVWoOdErgZ8In5e3688nZstTZuUDtrx8LFK2vxCc6ovEqSUT0PuIXLP6ezrSXrJRKhY93k0v8lIuBQRQtNCAq9DvF1sr35iRDf1BI1foiW7dB5ow7rAo/s1600/2kmtx_lgd.gif" /></a></div><div align="left"><br />
</div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">In the copper side view, you can see that there are three track etched inductors that resembles <b>'RCL' </b>Every corner and track width/length are calculated and then they are drawn so that each 'RCL' section becomes an inductor of required value. Never play with this; otherwise, optimum result could not be achieved.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">You need to use a laser printer or a high quality printer to get a printout of the drawings. First, save the picture to disk. Now try to print it from such a software which permits you to control print size. 'Paint Shop Pro' is such a software. Of course you can use any other software. Print the drawing so that copper side drawing is exactly 59mm X 59mm. Few trial will give you the perfect print. Now construct the PCB using 'Photo-etching' method so that all the tracks becomes exactly same as you are now seeing. Now drill the PCB carefully. The PCB is now ready to populate.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Start population according to the component mounting plan. You can also get a true size copy of this plan printed and glued to the PCB. This will help you work fast.Part of L3 is required to be constructed. This is described in parts list.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Please note that in the picture of the transmitter kit, capacitor C1 & C10 are not mounted by mistake and the kit is filmed. Please add these two capacitors. Try to keep all component leads as short as possible.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Now you need to design the dipole antenna to use with the kit.</span></div><div align="left"><br />
</div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;"><i>N.B: Believe it or not, a 2N2369 from Philips, used in the final power amplifier section, can give this much of range.</i></span><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;"> </span><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;"></span></div><div align="left"><br />
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</div><div align="left"><span style="color: magenta; font-family: Arial,Helvetica; font-size: large;"><b><u>Detailed Parts List:</u></b></span></div><div align="left"><br />
</div><div align="left"><span style="color: #ff0080; font-family: Arial,Helvetica; font-size: x-small;"><b><u>RESISTORS</u></b></span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R1 - 22K</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R2 - 100K</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R3, R7, R9 - 1K</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R4, R8 - 100E</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R5 - 390E</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R6 - 330E</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R10 - 15E</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">R11 - 10K</span></div><div align="left"><span style="color: #ff0080; font-family: Arial,Helvetica; font-size: x-small;"><b><u>CAPACITORS</u></b></span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C1, C3, C10 - 1n</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C2 - 100n</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C4,C8,C9 - 47pF</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C5, C11 - 10pF</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C6 - 100uF/25V Electrolytic</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C7 - 100pF</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">C12 - 3pF</span></div><div align="left"><span style="color: #ff0080; font-family: Arial,Helvetica; font-size: x-small;"><b><u>TRANSISTORS</u></b></span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Q1, Q2, Q3 - BC548</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Q4 - PN2369 (Plastic casing) or 2N2369 (Metal casing)</span></div><div align="left"><span style="color: #ff0080; font-family: Arial,Helvetica; font-size: x-small;"><b><u>MISC.</u></b></span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">L3 - 7 turns, 22SWG wire, 3mm ID, Close wound, Air core.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">Two hole binocular BALUN core, BALUN wire, 300 ohms TV feeder wire, </span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">JP1 to JP5 - All jumper wires.</span></div><div align="left"><span style="color: black; font-family: Arial,Helvetica; font-size: x-small;">This completes the Project. Please mail me with your feedback. It will really encourage me to give you more & more project like this.</span></div><div align="left"><span style="color: magenta; font-family: Arial,Helvetica; font-size: x-small;"><b><u> </u></b></span><span style="color: black; font-family: Arial,Helvetica; font-size: small;"> </span></div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com220tag:blogger.com,1999:blog-1428563853450024571.post-27497680943113346552011-06-26T23:12:00.000-07:002011-06-26T23:12:55.876-07:00Success story, making of my FM Transmitter.<div style="background-color: black; color: white;"><span style="font-size: large;"><b>I've tried to build (make) my own Fm transmitter from the very beginning of my boyhood but failed failed and failed. My first successful Fm transmitter was aired in 2001 when i was a student of class 12. After a long run of 4 years from class 9.</b></span></div><div style="background-color: black; color: white;"><span style="font-size: large;"><b><br />
</b></span></div><div style="background-color: black; color: white;"><span style="font-size: large;"><b>here i'll show you my recent 10 watt Fm transmitter testing circuit (battery powered exciter only due to security matter) and finally assembled cabinet (AC powered). </b></span></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiS9SZFm7aU0i0nmBQdlGa1sUx_ZG-fF3Bd_DDNULE6CshrNqs-3RTS-lvzHjDwXgE8hyNieyHY8DJOj-6BqNxj1iVl4EfAcYTQr-Foeq81XBr-EtSn9jpYmF_2879Obg_ra3zAEaX1ddg/s1600/2.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhljn2mUkNpPonC9M4FFRVg90V1blJafyIDHopyCtC9UEkWXUa4nM2pCZ0vZxz0YurrOl4pJdnZz6SGIMg2XqsdSJrq5ZbMuonc7mai-7uknxcqmLzLMqvKwjioVhDKp_NDOePeLqz9Uyc/s1600/1.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhljn2mUkNpPonC9M4FFRVg90V1blJafyIDHopyCtC9UEkWXUa4nM2pCZ0vZxz0YurrOl4pJdnZz6SGIMg2XqsdSJrq5ZbMuonc7mai-7uknxcqmLzLMqvKwjioVhDKp_NDOePeLqz9Uyc/s400/1.JPG" width="400" /></a></div><div style="text-align: center;"><span style="color: red;"> Transmitter after assambled</span></div><br />
<span style="font-size: x-large;"><b><span style="background-color: black; color: white;"> Click "Read More" to see the other photos........</span></b></span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiS9SZFm7aU0i0nmBQdlGa1sUx_ZG-fF3Bd_DDNULE6CshrNqs-3RTS-lvzHjDwXgE8hyNieyHY8DJOj-6BqNxj1iVl4EfAcYTQr-Foeq81XBr-EtSn9jpYmF_2879Obg_ra3zAEaX1ddg/s1600/2.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiS9SZFm7aU0i0nmBQdlGa1sUx_ZG-fF3Bd_DDNULE6CshrNqs-3RTS-lvzHjDwXgE8hyNieyHY8DJOj-6BqNxj1iVl4EfAcYTQr-Foeq81XBr-EtSn9jpYmF_2879Obg_ra3zAEaX1ddg/s1600/2.JPG" /></a><div style="text-align: center;"><span style="color: red;"> close view</span></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcqXeDQ-_Q4M-kU5cB3C9omYLI-eEcVqP_qizhdr4jGawyD_eFx5x0e7uI-rBEDJinKKpYdiubG4zrtztRquq-wC5_GPRCKO46JMig9LiFRknIxmqxHPEMN05FxjAdibI_hORgYNkZcME/s1600/3.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcqXeDQ-_Q4M-kU5cB3C9omYLI-eEcVqP_qizhdr4jGawyD_eFx5x0e7uI-rBEDJinKKpYdiubG4zrtztRquq-wC5_GPRCKO46JMig9LiFRknIxmqxHPEMN05FxjAdibI_hORgYNkZcME/s1600/3.JPG" /></a></div><div style="text-align: center;"><span style="color: red;">Heart of FM transmitter (the exciter)</span></div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com28tag:blogger.com,1999:blog-1428563853450024571.post-42245824119741238102011-06-17T02:09:00.000-07:002011-06-17T02:13:46.482-07:00ANTENNA DESIGN FOR FM TRANSMITTE<div align="center"><u><span style="color: red; font-size: medium;"><b> ANTENNA DESIGN</b></span></u></div><div align="center"><br />
</div><div style="background-color: yellow; color: black; text-align: left;"><b>There are two types of antenna for FM TRANSMITTE </b></div><div style="color: black; text-align: left;"><b>1. Ground pole Antenna </b></div><div style="color: black; text-align: left;"><b>2. Half-Wave Dipole Antenna</b></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJWihW_IABStT2Gnd2CsjmPEt_Nnax_jXd1Au8WYH4FIIkeS9qqFX19BOmO88T8oXdqIBWVztqBvw-GDAB8PGIiFNhoivEcBxCf7hJcN7rnj6U9A5jZewf7fj2BinsCvgEaQFLsMAspOk/s1600/GP_Antenna_A0.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJWihW_IABStT2Gnd2CsjmPEt_Nnax_jXd1Au8WYH4FIIkeS9qqFX19BOmO88T8oXdqIBWVztqBvw-GDAB8PGIiFNhoivEcBxCf7hJcN7rnj6U9A5jZewf7fj2BinsCvgEaQFLsMAspOk/s320/GP_Antenna_A0.jpg" width="240" /></a></div><div style="color: black; text-align: center;"><b> A ready made GP Antenna. </b></div><div style="color: black; text-align: left;"><br />
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</div><div style="color: black; text-align: left;"><u><span style="color: red; font-size: medium;"><b>1. Ground pole Antenna(GP)</b></span></u><b> </b></div><div style="color: black; text-align: left;"><b><br />
</b></div><div style="color: black; text-align: left;"><b>This Antenna is most widely used all over the world. For example, when you<a name='more'></a> see a police car it has a transmitter with Ground Pole Antenna The body of car serves as ground). It accepts load from 50 ohm source and has larger power output than Half-Wave Dipole Antenna.</b></div><div style="color: black; text-align: left;"><br />
</div><div style="color: black; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0dRfu2XYEZN9jJqRrdVhmFCC7KAOMzGGWkzZpMock3csIny1QJV1-gJMnH_glXSvFDzQ3JU0yOpY_qOJ30d6QLOe_ZtAIiq5Cn5MtJoLiYePdEzSPZ6ulumfjeA3kKzXw97P3I5o4cFM/s1600/gp_ant.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj0dRfu2XYEZN9jJqRrdVhmFCC7KAOMzGGWkzZpMock3csIny1QJV1-gJMnH_glXSvFDzQ3JU0yOpY_qOJ30d6QLOe_ZtAIiq5Cn5MtJoLiYePdEzSPZ6ulumfjeA3kKzXw97P3I5o4cFM/s1600/gp_ant.jpg" /></a><b><i> </i></b></div><div style="color: black; text-align: center;"></div><div style="color: black; text-align: center;"><br />
</div><table border="1" cellpadding="0" cellspacing="0" class="MsoNormalTable"><tbody>
<tr><td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">Frequency</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">Radiator - B</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">Radials - A</span></b></div></td></tr>
<tr> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">108MHZ</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">660</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">693</span></b></div></td></tr>
<tr> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">104MHz</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">684</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">720</span></b></div></td></tr>
<tr> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">100MHz</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">713</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">749</span></b></div></td></tr>
<tr> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">90MHz</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">792</span></b></div></td> <td style="padding: 1.5pt; text-align: center;"><div class="MsoNormal"><b><span style="color: black; font-family: Verdana; font-size: 10pt;">819</span></b></div></td></tr>
</tbody></table><div style="color: black; text-align: left;"><br />
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</div><div style="color: black; text-align: left;"><span style="color: red; font-size: medium;"><b> 2. <u>Half-Wave Dipole Antenna Or Open Dipole </u></b></span><u><span style="color: red; font-size: medium;"><b>Antenna</b></span></u></div><div style="color: black; text-align: left;"><br />
</div><div align="justify"><b>It accepts load from 75 ohm source and has much smaller power output than Ground Pole Antenna. Use this antenna only when you don't have GP Antenna.</b></div><div align="justify"><b>Construction: Two aluminum rods ,each of length "L" in meters are joined together through an insulator as shown in fig. From center, 75 ohm cable is feeded just like ordinary TV antenna.</b></div><div align="justify"><br />
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</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmUAyCynhEiVDBXE9yH3T6jlDPAjE_XVOfx9f0gLOJMXq4gt0olfSrpA66QULwnS8zvGxqeZ_OuFqp1fQrlpW-s4WZXXZHsZhYxkLpQ4Z9gpwEibmrTmhZkJdi-DTq1POsjp8GW-dyOi0/s1600/dipole.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmUAyCynhEiVDBXE9yH3T6jlDPAjE_XVOfx9f0gLOJMXq4gt0olfSrpA66QULwnS8zvGxqeZ_OuFqp1fQrlpW-s4WZXXZHsZhYxkLpQ4Z9gpwEibmrTmhZkJdi-DTq1POsjp8GW-dyOi0/s1600/dipole.jpg" /></a></div><br />
<div class="separator" style="background-color: white; clear: both; color: yellow; text-align: center;"><span style="font-size: large;"><a href="http://www.blogger.com/goog_1977092651" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><br />
</a></span></div><div class="separator" style="clear: both; text-align: center;"><span style="background-color: black; color: yellow; font-size: large;">I'll discuss the design, calculation of length, wire to be used and set-up details of FM TRANSMITTER Antenna very soon in this blog. so stay tuned.</span></div><div class="separator" style="clear: both; text-align: center;"></div><div align="justify"><br />
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</div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com20tag:blogger.com,1999:blog-1428563853450024571.post-47444528568956013182011-06-16T23:46:00.000-07:002011-06-16T23:49:58.280-07:001 Watt simple FM Transmitter with 1-2 km range!<h2 align="center" style="font-weight: normal; text-align: center;"><u><span style="font-size: large;"><b>1 Watt FM Transmitter</b></span></u></h2><div align="center" class="MsoNormal" style="text-align: center;"><br />
</div><span style="font-size: 18pt;">This is simple 1 Watt FM Transmitter circuit. This circuit will be able to cover 1-2 KM range with a single pole antenna of 20 feet! </span><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwIC8GNc-45_5hhoRYmTbODN0gsg0tXir93dW_2MTLFJ2rSvUMuJlWnfKnSfT9q2MDwx7Ed5Y54fSiALaA9SUD_UZQSf1LlM8nVa3rZ3YKBxAGC0gQIYlO1nJPqqfOp0a30VtsoNh3bx0/s1600/1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="188" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwIC8GNc-45_5hhoRYmTbODN0gsg0tXir93dW_2MTLFJ2rSvUMuJlWnfKnSfT9q2MDwx7Ed5Y54fSiALaA9SUD_UZQSf1LlM8nVa3rZ3YKBxAGC0gQIYlO1nJPqqfOp0a30VtsoNh3bx0/s320/1.jpg" width="320" /></a></div><div class="separator" style="clear: both; text-align: center;"></div><div class="separator" style="clear: both; text-align: center;"><b><span style="color: red;">Click on picture to view the large size</span></b></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: left;"><u><b><span style="font-size: large;">Descriptions</span>:</b></u></div><div class="separator" style="clear: both; text-align: left;"><span style="font-size: 18pt;">P1 act as condenser microphone volume level. For FM, coil will be small. Use thin<a name='more'></a> gauge enamel magnet wire. the diameter of coil will be a couple mm: use ink tube from pen to form, and try 8-12 turns. Small inductance coils make for much guess work.</span></div><div class="separator" style="clear: both; text-align: left;"><br />
</div><h3><u><span style="font-size: 18pt;">Components/parts List:</span></u></h3><table border="0" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="margin-left: 7.5pt; width: 100%;"><tbody>
<tr><td style="padding: 0.75pt;"><div class="MsoNormal" style="margin-bottom: 7.5pt;"><span style="font-size: 18pt;">R1=220K<br />
R2=4.7K<br />
R3,R4=10K <br />
R5=100ohm</span></div></td> <td style="padding: 0.75pt;"><div class="MsoNormal" style="margin-bottom: 7.5pt;"><span style="font-size: 18pt;">C1,C2=4.7uF Electrolytic<br />
C3,C4=1nF<br />
C5=2-15pF<br />
C6=3.3pF</span></div></td> <td style="padding: 0.75pt;"><div class="MsoNormal" style="margin-bottom: 7.5pt;"><span style="font-size: 18pt;">Q1=BC547C<br />
Q2=2N2219A<br />
P1=25K MIC=Electret Condenser Type</span></div></td></tr>
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</div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com55tag:blogger.com,1999:blog-1428563853450024571.post-91520527963827478642011-06-16T23:25:00.000-07:002011-06-16T23:29:28.189-07:00Construction of Air Core Coil for FM transmitters<div style="color: red;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjyFtiw-pViNVTiWQonH-95jjJwCrzmlEJ3Wv2KI1v5-sv1x5PVFybsjkB_wFfKosvPybMiUFUvA1_JYsgLeW8pnH4VE9txiAwbDt3_kRYhpjSDDX9mqaQi_mVGHtjDvhIsxp0iimEi98/s1600/10.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjjyFtiw-pViNVTiWQonH-95jjJwCrzmlEJ3Wv2KI1v5-sv1x5PVFybsjkB_wFfKosvPybMiUFUvA1_JYsgLeW8pnH4VE9txiAwbDt3_kRYhpjSDDX9mqaQi_mVGHtjDvhIsxp0iimEi98/s1600/10.jpg" /></a></div><b><span style="font-size: large;"><span style="font-family: Verdana,sans-serif;">Just follow the steps as shown in the following pictures to make the air core coil for your Fm transmitter</span></span></b><span style="font-size: large;"><span style="font-family: Verdana,sans-serif;">. </span></span><br />
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<div style="text-align: center;"> <span style="font-size: large;"> <b><span style="background-color: yellow; color: blue;">Click "Read More" to view details</span></b></span></div><br />
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</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQAAI477X5mWNk1gSthSbiQDws7ed4GrgQ7fUFbKhdvYz98vP8K9HgHxYuQAXlic3gewJGQ-YY5b1hcFk4NBaNVVzx-zCmINDBp2o_yqCjjUmwaeKR_7XREQ3V5dFcKkelsxaSMM4tXOk/s1600/1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="138" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQAAI477X5mWNk1gSthSbiQDws7ed4GrgQ7fUFbKhdvYz98vP8K9HgHxYuQAXlic3gewJGQ-YY5b1hcFk4NBaNVVzx-zCmINDBp2o_yqCjjUmwaeKR_7XREQ3V5dFcKkelsxaSMM4tXOk/s320/1.gif" width="320" /></a></div><div style="text-align: center;"><span style="background-color: white; color: red;"> </span><b style="background-color: white; color: red;">1. Select magnet wire of specific gauge as described in circuit (buy from motor/fan repairing shop).</b></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIef51FuMnvwpVYL6wYsC2HkR9APs1gl71XHevl1ea2L1zoBTqlRh-N9myNBecAZ_8hD5OhyS0iFxQ2veXlY32kmaWih86yBJL06MZJ5194kwpsAGfUFUV4rLfH9DqpAk1UZeP-FWIOqQ/s1600/4.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIef51FuMnvwpVYL6wYsC2HkR9APs1gl71XHevl1ea2L1zoBTqlRh-N9myNBecAZ_8hD5OhyS0iFxQ2veXlY32kmaWih86yBJL06MZJ5194kwpsAGfUFUV4rLfH9DqpAk1UZeP-FWIOqQ/s1600/4.JPG" /></a></div><div style="text-align: center;"><b style="color: red;"> 2. wound (round up) the wire on a pencil, pen or screw driver of correct diameter as stated in circuit diagram.</b></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizATSOH9eNi9Lf-vjfT3PrMtNfiKKbKpXKQ6NoohYyvMa9H19ExTTT0PTBaxxTSW-zZUvBYnpbf5_eCRVhC2ZQ7kjzgXWk2FvrDFZvNKTnrEVJM3yTlcBRvbEX0c6rdV5C1KuBS1P7-Nk/s1600/5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizATSOH9eNi9Lf-vjfT3PrMtNfiKKbKpXKQ6NoohYyvMa9H19ExTTT0PTBaxxTSW-zZUvBYnpbf5_eCRVhC2ZQ7kjzgXWk2FvrDFZvNKTnrEVJM3yTlcBRvbEX0c6rdV5C1KuBS1P7-Nk/s1600/5.jpg" /></a></div><div style="text-align: center;"><b style="color: red;"> 3. don't make any half turn without any guide from your circuit text. Remove the pencil, pen or screw driver .</b></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrqXKA8yPLVQGjV3lYXQI2xqD8vUrzOMTTsa5QhjOTsTsmQ4iZ1DHWVqn_nyt7zjrRSLp-zOiqEpkpOe9Sr-tyfnQ5AcBTwJ5rp2a5Ek4JyiXYeLxK4zE502WDNgCmLsPmg5xgCPsh5Xg/s1600/7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrqXKA8yPLVQGjV3lYXQI2xqD8vUrzOMTTsa5QhjOTsTsmQ4iZ1DHWVqn_nyt7zjrRSLp-zOiqEpkpOe9Sr-tyfnQ5AcBTwJ5rp2a5Ek4JyiXYeLxK4zE502WDNgCmLsPmg5xgCPsh5Xg/s1600/7.jpg" /></a></div><div style="text-align: center;"><b><span style="color: red;"> 4. Your Coil is almost ready, Cut the extra length of leg's and solder the both leg (pins) of your coil. try to keep the length of leg as minimum as possible. it'll give stability of your frequency.</span></b></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJb4HvdnmimkgHbma0nvA8oCOg4GEISFTj1pJLRkLZ5C1lWFhx2rGcagbw4oeoeDgAWWnBhg4cq0rcGlkknc86ewRTjK90npj5_FR67nYS9TAdh-_VUyUnEJ85NzyEaWkN3KncDwVl4l0/s1600/8.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJb4HvdnmimkgHbma0nvA8oCOg4GEISFTj1pJLRkLZ5C1lWFhx2rGcagbw4oeoeDgAWWnBhg4cq0rcGlkknc86ewRTjK90npj5_FR67nYS9TAdh-_VUyUnEJ85NzyEaWkN3KncDwVl4l0/s1600/8.jpg" /></a></div><div style="text-align: center;"><b><span style="color: red;"> 5. Shrink or expand the coil as the required length as stated in your desired circuit text.</span></b></div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikbS1zcPsRcgcmWceM2-ktNAk0-iA-a1LAj4uQZaQ9p71O3leRqKlycvjrhm00FUGtPS1n-8Cg_4MSrZ6tZSCVVzjjOBxy5L0dBviAcGUqeySr3GsT8JjUCaPDuoEwMlpFpFNHxu5rSHU/s1600/9.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEikbS1zcPsRcgcmWceM2-ktNAk0-iA-a1LAj4uQZaQ9p71O3leRqKlycvjrhm00FUGtPS1n-8Cg_4MSrZ6tZSCVVzjjOBxy5L0dBviAcGUqeySr3GsT8JjUCaPDuoEwMlpFpFNHxu5rSHU/s1600/9.jpg" /></a></div><div style="text-align: center;"><b><span style="color: red;"> 6. Here is your coil</span></b></div><br />
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</div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com7tag:blogger.com,1999:blog-1428563853450024571.post-68322343137633425802011-06-16T02:03:00.000-07:002011-06-16T02:17:33.794-07:00USB FM Transmitter Circuit for PC and Laptop<div class="separator" style="clear: both; text-align: left;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvDp4ksz2KsvWY5aXtbTrayilHVPZRNW2BaI5KGUlt9riwCxSwkjelt3yZ7MumLhheQSIoAD_RhZatGimvM-P7V3YDZL0Ec0Ectba6Axx8KvFaJE8dbybFUGrFxDpY9oAtV3gce0tOdPw/s1600/USB_FM_Transmitter_Prototype.jpg" imageanchor="1" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjvDp4ksz2KsvWY5aXtbTrayilHVPZRNW2BaI5KGUlt9riwCxSwkjelt3yZ7MumLhheQSIoAD_RhZatGimvM-P7V3YDZL0Ec0Ectba6Axx8KvFaJE8dbybFUGrFxDpY9oAtV3gce0tOdPw/s1600/USB_FM_Transmitter_Prototype.jpg" /><span style="color: black;"> </span></a></div><div style="text-align: justify;"><span style="color: black;">Here's a small FM transmitter ciruit for your desktop or laptop to enjoy the movie and music from a distance. This FM transmitter, which is powered by USB, recovers output on your computer or your MP3 player to the relay on the tape FM (frequency 108 MHz). For Assemblying this FM transmitter kit, an electronics hobbyist will have built in about 30 minutes.</span><br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7TqPGW5eZAWA3JiGOpAzhQeMOYKureh-6a4DYJgUnIIvH3y_BXnv-ZzMZtuIJgj8niJK_zZr1M9UnpXBYP7FJ0WXhdynTpBZpkU2RUhQElETv9Nar08oM1CUCyjwSL9RRxDlGwWI9zME/s1600/USB_FM_Transmitter.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="195" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7TqPGW5eZAWA3JiGOpAzhQeMOYKureh-6a4DYJgUnIIvH3y_BXnv-ZzMZtuIJgj8niJK_zZr1M9UnpXBYP7FJ0WXhdynTpBZpkU2RUhQElETv9Nar08oM1CUCyjwSL9RRxDlGwWI9zME/s320/USB_FM_Transmitter.jpg" width="320" /></a><span style="color: black;"> </span></div><div class="separator" style="clear: both; text-align: center;"></div><div style="color: black;"><br />
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</div><div style="color: black;"><b>FM Transmitter Construction</b><br />
It is not necessary to drill the transmitter PCB. All components will be soldered to the plate with their legs folded. </div><br />
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The two transistors and the LEDs are polarized:<br />
The transistor has a flat side, the LED a foot longer than the other is the anode (A), the other is the cathode (K). The audio cable (minijack) must be transformed from a stereo cable into a cable.<br />
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Mono Sound:<br />
Soldering together the white and red cables, leaving aside the yellow cable (mass). The frequency setting will be turning the variable capacitor gently with a screwdriver or thin cardboard but rigid.<br />
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<b>FM Transmitter Parts List</b><br />
* 1 Ohm resistor 510 (green - brown - brown)<br />
* 100 resistor 1 kOhm (brown - black - yellow)<br />
* 1 MOhm resistors (brown - black - green)<br />
* 1 capacitor 0.1 uF (0.1)<br />
* 1 nF capacitor 47 (0.047)<br />
* 1 capacitor 4.7 pF (479)<br />
* 2 pF capacitors 22 (22)<br />
* 1 variable capacitor 1.5 pF ... 15<br />
* 2 transistor BF 246 (F246A)<br />
* 1 red LED<br />
* 1 audio cable (minijack)imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com15tag:blogger.com,1999:blog-1428563853450024571.post-67640365805589005272011-06-16T01:45:00.000-07:002011-06-16T02:23:30.671-07:00Simpliest 2 watt FM transmitter with PCB and details<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5wVtV4B4NogEh0kGhT3e_GDvlspkMbbYtnDNqujwUyuHz8yJVyyN-YnyL5lbt-cHomnfQv5b6c50NxcAHNhYs2xGp-UIJRRxwHxJE6cjHPBk6U_CfgVzuLlbIppS0iubM0lfRM4LP5mc/s1600/FMX3.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="124" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5wVtV4B4NogEh0kGhT3e_GDvlspkMbbYtnDNqujwUyuHz8yJVyyN-YnyL5lbt-cHomnfQv5b6c50NxcAHNhYs2xGp-UIJRRxwHxJE6cjHPBk6U_CfgVzuLlbIppS0iubM0lfRM4LP5mc/s320/FMX3.JPG" width="320" /></a> <br />
USE DIPOLE ANTENNA FOR MAXIMUM RANGE (COULD BE UP TO 10 KM IN GOOD WEATHER). TUNE BETWEEN 88-108 MHz WITH C5. BB-204 COULD BE REPLACED WITH CONVENTIONAL LED (BIG) WITH REVERSE BIAS (NO LIGHT GIVEN IN CORRECT POLARITY). 9V POWER FOR 2KM WITH GOOD SOUND QUALITY AND GRADUALLY UP TO 18V FOR 10 KM RANGE WITH POOR QUALITY OF SOUND. BEST OF LUCK. </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOpJYtkbzw2Z7nqP8osJAbg4nWOW2fT-rR6TCUCi6Lvc4LR9MooCx2kBEfQl6ooYff8MPxCfv1PxyvDRyrmzCQsIFTPg9fVqQc6w1ugSXWDoIdKjtMADeQELC3IafcMdrHZUMOs8gCH9c/s1600/FMX0.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcXnYmn8LBNyDBtKUBF2KvcWSGClLXLLNxA5A_pBZzo4puhyMeUjj7VLg0T0Ve6mciE10ui3FczPoxiM6djRvGcUvXxabSGPUzwKeag_6qKl7lZYggLpAixiGjC0yQ0fxHTotd-MF-e8E/s1600/FMX4.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="124" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcXnYmn8LBNyDBtKUBF2KvcWSGClLXLLNxA5A_pBZzo4puhyMeUjj7VLg0T0Ve6mciE10ui3FczPoxiM6djRvGcUvXxabSGPUzwKeag_6qKl7lZYggLpAixiGjC0yQ0fxHTotd-MF-e8E/s320/FMX4.JPG" width="320" /></a></div><div style="text-align: center;">www.fmradio-transmitter.blogspot.com</div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com75tag:blogger.com,1999:blog-1428563853450024571.post-49629400771669492442011-04-16T00:28:00.000-07:002011-04-16T00:36:33.847-07:00Coilless FM transmitter !<div dir="ltr" style="text-align: left;" trbidi="on"><div style="color: purple;"><span style="font-size: large;"> If you are in the problem to make perfect coils for FM Transmitter then this is your time to go on..... See this coil less and easy FM Transmitter.</span></div><br />
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The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.<br />
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Since these inverters are in parallel the output impedance will be low so that it can directly drive an aerial of 1/4th wavelength. Since the output of N4-N6 is square wave there will be a lot of harmonics in it. The 9th harmonics of 10.7Mhz (96.3Mhz) will hence be at the center of the FM band .<br />
N1 is working as an audio amplifier. The audio signals from the microphone are amplified and fed to the varycap diode. The signal varies the capacitance of the varycap and hence varies the oscillator frequency which produce Frequency Modulation.</div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com2tag:blogger.com,1999:blog-1428563853450024571.post-83504911052152269352011-04-16T00:13:00.000-07:002011-04-16T00:34:06.698-07:001 km. FM Transmitter<div dir="ltr" style="text-align: left;" trbidi="on"><span style="font-size: large;">Description</span><br />
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This one is a high power long range (use yagi antenna) FM Transmitter that provides very good frequency stability in about 1km range and very good microphone sensitivity. It can be used inside guitars, as a part of remote control systems or in other similar applications.<br />
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The features said above are achieved by including an RF amplifier stage with 10dB gain and AF preamplifier stage to boost the modulation.<br />
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The circuit construction is simple. L1 is integrated into the PCB with 3.25 turns. Transistors are not critical. The BC547s can be replaced with any small signal NPN type transistor and BC557 is a general purpose PNP transistor so it can also be replaced easily.<br />
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The power consumption is low. The finished circuit draws about 30mA. A single 9V battery is ample to power the FM wireless microphone.<br />
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The PCB file is given in the download section of the project page. You should check Harry's page for more detailed information about the components, PCB modifications and the other features of the circuit.<br />
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if you need more details then post a comment below </div>imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com38tag:blogger.com,1999:blog-1428563853450024571.post-72274259296192805852010-12-30T03:33:00.001-08:002010-12-30T03:33:41.092-08:00Site will be presented with minimum 20 fm transmitter and bug circuits of different range and power. Coming soon. . .Fm transmitter of 20 km range to 100 meter range will be available here very soon.imonhttp://www.blogger.com/profile/06883384816184244952noreply@blogger.com2