If you have built our FM exciter or EN1619 or another VFO exciter (we have proposed a lot) broadcasting in FM in the 88-108 MHz band, you'll be able to increase its power and carry up to 15 W in order to cover a far greater distance than you reach with your 250 mW. You'll find it easy to build yourself this linear amplifier and you can attack it with any FM generator, provided that its output signal (which will connect to the power amp) has a power not exceeding 300 mW. That's what sound to a large property, and if you get the permissions, create a small FM station in a village or township.
Specifications PD55015
Max Signal Input: 300 mW in the FM band
maximum drain-source voltage: 40 V gate-source voltage 
Maximum: 20 V Current drain maximum
: 5 A Maximum: 20 V Current drain maximum Maximum power output: 16 W average power
Gain: 14 dB Frequency average working: 500 MHz
Maximum frequency: 900 MHz When performing the exciter EN1619, we recommend that you use, but if you needed to bring power to about twenty watts, to benefit from a broader or even create a small radio station in a village or quartermaster broadband hybrid module 88-108 MHz PHILIPS-MF20 CTS (input ⇒ output 100 mW to 20 W power 12 VDC typical), in fact, we kept some of the 80's and it works very well ... unfortunately, this component is now found, even among specialists in ancient and obsolete components. We surfed for hours on the sites most improbable and, lo and behold, even Philips seems to have forgotten this module once he made when he was allied to France with La Radiotechnique Compelec (CTS): if we did not even a handful on hand, with all the above references not erased, we would believe to have dreamed! We remember it well were two others: the ML20 for the range below 68-88 MHz and another for a higher range that we have forgotten the name and the range covered. If one of our readers have any information on the MF20 (and a fortiori if he knows a way to get them), it contacts the writing and we would appreciate him. Once this phase despite past we left in search of a worthy component of modern follow an exciter to DDS in order to increase the signal strength that synthesizes so well and we found the gem of the Power MOSFET SGS-THOMSON PD55015 (see above technical characteristics) is more economical than a VHF power transistor TRW, Motorola and Philips. It is capable of delivering 16 W at 900 MHz (we will work to a tenth of its peak frequency) of more ... this component is very well-stocked as long as it lasts! We feed it with a DC voltage of 12-15 V, which will consume about 2.2 to 2.5 A for an RF power output of 10 to 15 watts ... not bad for a component available within fifteen euro! Go and see the price of a Philips BLY87, 88 or 89 (knowing it takes two to gain a comparable 60) ... Indeed, PD55015 has a gain (100 MHz):
G = Pout: Pin
with Pout and Pin W or mW
15: 0.25 = 60 (this stage amplifies the input signal 60 times).
Figure 1: Appearance and pinout (top view: gate-source-source-drain) MOSFET PD55015, only the semiconductor assembly (except the controller).
note, the mark-keyed U indicates that integrated circuit one blade spring (when it is below, as shown in the figure, the trigger is on the left and right drain).
Figure 2: Photograph of a prototype of the amplifier linear FM of 10-15 W. All components are soldered directly on the slopes of tinned copper and top ground plane (the printed circuit board that is a double sided plated through holes in the ground plane is less than the entire surface of the back is not seen Here one sees the holes and connect the two ground planes above and below).
The wiring diagram of linear amplifier All the wiring diagram in Figure 3 expands on this power MOSFETs MFT1. First problem to implement it and learn everything he is able give us: to adapt the value of its input impedance around 4-ohm characteristic impedance at the output of our EN1619 exciter which is 75 ohms.
Note: If you use an exciter or other VFO or RF generator whose output impedance is 50 ohms, do not despair because the combination of these two impedances 75 and 50 ohms produces only a SWR of 1 , 5:1, which is absolutely ridiculous in terms of loss of power (especially as you will in this case may reduce your Pin-excitation power is adjustable so it is perfect) . To achieve this adaptation, we must interpose a circuit that lowers the impedance of 75 ohms 4-ohm MOSFET. It must also adapt the value of the output impedance of the latter (around 6-8 ohms) to the characteristic impedance output, that is to say, the characteristic impedance of the coaxial cable that we intend to use to power (also called attack) the selected antenna (for starters we recommend a half-wave dipole): 52 or 75 ohms? This time the matching circuit will raise the value of the impedance of 6-8 to 52-75 ohms.
If we go further the need for these two adapters impedance entry and exit of the MOSFET, the bulk of the signal would be lost and the power available at the output to the antenna would be zero (this floor would be more an attenuator amplifier). Note: If you want more information on impedance matching, review your e-Learning courses from scratch (Part Two) ... or make the acquisition as a CD. Although few components around the IC. Let's start with BNC input, the left, as shown in Figures 3, 4, 5, 6, 13 and 14. It receives the signal from the exciter or VFO or RF generator and the signal taken off our EN1619 exciter has an output of 250 mW. Be careful though, if you use another exciter latter, know more than a few mW (that the 250 mW) output power will exceed a few watts (remember, the gain is 60! ) and it may damage or destroy the MOSFET power dissipation capability which is certainly high but not infinite.
However, with less than 250 mW excitement you can get the output signal power below 10 W. The BNC input is connected to the trigger PD55015 through the C1-C2-C3 and L1 (the four inductors L are winding and it is very easy, as shown in Figures 8, 9 and 10): these are the components that realize the impedance matching entry we talked about earlier (75 to 4 Ohm). To operate as a MOSFET RF amplifier (we say more RF for Radio Frequency), we need to polarize its gate with a fixed voltage of about 2.7 V to get it, we climb a bridge of resistors R2 -R3 to the stabilized output of the regulator IC1 MC78L05 providing a voltage of 5 V. The source of this MOSFET consists of two blades located in the same axis (see Figure 1) are grounded (as shown in Figure 4a, they are connected to the shortest, VHF forces, that is to say on the top ground plane, covering the entire surface left by trail used by the signal and those that carry the polarization of the trigger). And here we are on the other side of the power MOSFETs, that is to say, already on the side of the BNC output. The output pin-the-drain is connected to L2 and L3. JAF1 the choke (the good old VK200 core multitrou who needs no introduction) prevents any residual RF (oh sorry, HF) to enter the track positive and go to self-oscillate and the external power regulator IC1. C10-C11, connected to the junction of L2 and JAF1, are used instead to prevent the same RF going to lose the weight she did anything useful to do.
On the drain was installed L3 with C12 and C13, is used to adjust the output impedance of the MOSFET (6-8 ohms) to the characteristic impedance of coaxial cable (52 or 75 ohms). L4, with C14 and C15, is a lowpass filter that passes only frequencies below 120 MHz and prevents all those above 130 MHz to achieve l’antenne et de risquer de perturber les fréquences voisines (par exemple de créer des interférences pouvant être gênantes pour l’aviation civile).
Cet ampli linéaire de puissance RF peut être alimenté par une tension continue comprise entre 12 et 15 V et il consommera un courant allant de 2,2 à 2,5 A (environ, cela dépend entre autres de la fréquence de travail, de la puissance d’excitation et de l’adaptation de l’entrée et de la sortie).
Figure 3 : Schéma électrique de l’amplificateur linéaire FM.
Figure 4a : Schéma d’implantation components of the linear amplifier FM. The MOSFET is mounted MFT1 cue-keyed U down (legs source "watch" the two holes of the heatsink). The regulator IC1 is to assemble flat-keyed reference-oriented C6. The JAF1 JAF2 and the famous VK200, are core multitrou (they avoid the HF does self-oscillate or even food regulator found upstream). As for the impedance of the BNC coaxial cable from the dipole antenna (50 or 75 ohms), it did not matter too much: the difference between 50 and 75 ohms produces only ROS of 1.5:1, which is very acceptable. By cons, if you choose a directional antenna, Yagi or log-periodic or collinear, take the 50 ohm coaxial cable (or 52, it is the same), 10 mm in diameter if the cable must exceed a length of several meters (a BNC / N are required) and take the "Pope" low losses beyond 10 meters (and even below).
Figure 4b-1: Drawing to scale 1, double-sided PCB with plated through holes of the plate of the linear amplifier FM, solder side, where all components. 
Figure 4b-2: Drawing to scale 1, double-sided PCB with plated through holes of the plate of the linear FM, side and bottom ground plane facing the sink (this must all face well be burned because the lower ground plane passes the hot spot of the two BNC I / O). 
Iist R1 ........ R2 330 ........ R3 220 ........ 270
C1 ........ 4.7 nF ceramic VHF C2 ........ 51 pF ceramic VHF
C3 ........ Adjustable 7-105 pF (purple) C4 ........ 100 nF multilayer C5 ........ 1.5 nF ceramic VHF C6 ........ 100 nF multilayer C7 ........ 100 uF electrolytic
C8 ........ 100 nF multilayer C9 ........ 220 uF electrolytic C10 ....... 4.7 nF ceramic C11 VHF
....... 100 pF ceramic C12 VHF
....... 51 pF ceramic C13 VHF
....... Adjustable 5-65 pF (yellow) C14
....... 27 nF ceramic C15 VHF
....... 4.7 nF ceramic VHF
L1 ........ air coil turns on three 7 mm diameter (see Figure 8)
L2 ........ air coil turns 5 on 7 mm diameter (see Figure 9)
L3 ........ air coil turns on three 7 mm diameter (see Figure 8)
........ L4 air coil turns 6 on 7 mm diameter (see Figure 10)
JAF1 ...... choke VK200
JAF2 ...... choke VK200
MFT1 ...... MOSFET PD55015
IC1 ....... regulator MC78L05
TAA ....... dipole or other assistance from 88 to 108 MHz
Figure 5: Installation in plastic housing with front and rear drilled and etched aluminum, seen from behind. The plate is fixed to the bottom with four adhesive spacers.
Figure 6: Installation in plastic housing with front and rear aluminum punched and screen printed seen before. The two BNC input (left) and output to the antenna (right) are not screwed on the front but mounted directly on the PCB. The supply voltage of 12-15 V between the rear panel using a flat cable R / N via a password-son.
Figure 7: Pinouts of the regulator transistor TO92 type case "half moon" (the flat-keyed provides a benchmark) and bottom view of the adjustable capacitor (M are the two pins short-circuit and are welded to the top ground plane, the pin is welded C chokes on the slopes, see figure 4a). 
The practical realization of the linear amplifier This is not surprising for you if you have already mounted an RF power amplifier: two sides of the printed circuit includes a ground plane connected by holes metallized, and the lower ground plane covers almost the entire surface of the plate (it will be turned toward the flat surface of the sink, as shown in Figure 12) and the top ground plane fills the seat left vacant by the tracks or positive carrying the signal. It is on the face, one would tend to call "components", that all components are in fact mounted, but also on that side they are welded (or this is not a CMS!) When you have completed the double-sided PCB with 4b-1 and 2 shows a scale drawing or you you have purchased, immediately mount the plate on the heatsink fins, using two bolts located near the MOSFET source pins, as shown Figures 11 and 12 and let this set aside. Make the four inductors (L1 and L3 are identical), as shown in Figures 8, 9 and 10 by winding the exact number of turns on a rigid cylindrical (Like a tail bit) than 7 millimeters in diameter and spacing them regularly turns to the solenoid has the required length (after welding, you can "fix" this somewhat spacing). Use copper wire 1 mm in diameter, you can take a single strand wire insulated rigid plastic strip that you carefully without scratching and you can solder to the iron. You can also buy tinned or silver thread.
Resume platinum with its heatsink and attach great detail the power MOSFETs, without mistakes in its orientation (see Figures 2, 4 and 13): its source pins are welded on both sides of the enclosure to the mounting holes sink to the plate, the trigger is on the left and right drain. Do good welds (no welding or cold bonded in excess and then remove the excess of flux with an appropriate solvent): Solder the trigger and then wait until it cools; solder pin below the source, then wait until it cools ; solder the drain and wait until it cools, then solder the pin above the source and cool the area. The bearing surface of the power MOSFETs must be flush with the surface of the PCB, please not to be coated with a thin even layer of thermal paste with silicone (white).
Solder the four coils L1 to L4. First, make sure to weld the ends are not oxidized (if they are, revive them and galvanize them). Then shorten these ends that you solder on printed circuit tracks, so that the solenoid coils that are to be maintained at about one millimeter from the surface of the plate. Solder these coils according to the best length, and center it well over the ends on the slopes of destination, as shown in Figure 4a. Once sealed properly, edit if necessary spacing of the turns to make it regular, while respecting the length of said coil 8, 9 and 10. Before welding L1, R1 solder (having shortened legs) against any surface: the endpoints of the two components are the same. In the aftermath, go to R2 and R3 shorter against the surface. When done and that these welds were tested, get the two trimmers: the three legs (see Figure 7) must be shortened and flattened so that these components are very close to the surface of the PCB. C3 (purple) has a welded pin C in the angle of the track where you have soldered the end of L1 and C2 where you weld (see Figure 4a), M solder the pins on the earth plane. In the process, solder (still with remnants of legs as short as possible) C2 and C1 then insert the BNC input (model PCB) and solder it in five points. You're done for the input circuit (trigger side).
C13 (yellow) at its C pin welded into the corner of the runway at 90 ° between L3 and L4 and pin M on the ground strip (all still in short). In the process, solder the shorter C12 C14 and C15 and then turn up the BNC output (model PCB) and solder it in five points. You're done with the output circuit.
Note: As the figures show, the two side mounted BNC will lower ground plane and are welded onto the tracks and the ground plane above.
Refer now at the top of the plate and solder the choke coils and JAF1 JAF2 (their nucleus presses against the surface of printed circuit board). In the process, solder C10 and C11 and C5 and finally C4, C6 and C8 (this order is not imperative, but our list, you can not forget anything). Now solder the regulator IC1 Landmark flat-keyed "looking" C6, which his leg E is connected by the trail of the top edge of the plate. M is the pin to ground (as the other end of C6) and the welded pin S on the track up to the gate G. Finally solder the two electrolytic capacitors, + on the track and power - in terms of mass.
Note: If you have trouble identifying the capacity of capacitors on which it is not written in clear, here are some useful information.
- brown capacitor marked 104 is a 100,000 pF (= 100 nF)
- scored 102: is a 1000 pF (= 1 nF)
Check at least twice that you made no mistake (inversion of components, resistors and capacitors) and your quality of welds and connections are very short. Remove
well the rest of flux (amber and crystalline appearance) with an appropriate solvent (if necessary, ask our advertisers).
Figure 8: For winding the inductors L1 and L3, take a 7 mm drill bit on its tail and wrap 3 turns of bare copper wire 1 mm in diameter, the space often turns to get a head coil of 10 mm (naturally, then remove the drill!).
Figure 9: For the choke winding L2, take a 7 mm drill bit and wrap its tail 5 turns of bare copper wire 1 mm in diameter, the space often turns to get a length of coil of 10 mm (naturally, then remove the drill!).
Figure 10: winding the coil L4, take a 7 mm drill bit and wrap its tail 6 turns of copper wire 1 mm in diameter, the space often turns to get a length of coil of 12 mm (naturally, then remove the drill!). 
installation in the housing As shown in Figures 5, 6 and 14, is a plastic box with front and rear aluminum drilled and silk-screened (together with the exciter EN1619). Mount the plate and sink (secured by two bolts near the MOSFET) at the bottom of the cabinet with four adhesive spacers (see Figures 5, 6, 11 and 12). The two BNC then leave the front. Hole in the rear panel, install a password-son and made into rubber cord R / N that you solder (note the polarity reversal would be fatal to any MOSFET that is not protected): the black wire directly on the top ground plane and the red wire on the runway positive supply (see Figures 5-6). Do not close the lid of the box, because you'll have to make adjustments also. Do not turn on but preparing a stabilized power supply capable of providing a voltage of 12-15 V at a current of 3 A (5 A if you like having a margin of order 2). Indeed, your edit will consume 2.5 A. To perform these settings, you'll use, not an antenna, but a probe of charge and first you will have to realize it. 
Figure 11: Under the circuit board (where the lower ground plane covers the entire surface), attach the heat sink fins (to dissipate heat generated by the power MOSFET) with two through bolts, as shown also Figure 12 (the two holes for fixing this are indeed very close MFT1 to ensure good mechanical contact / local thermal). The other four holes of the plate are then used to fix the bottom of the plastic casing with four self-adhesive plastic spacers, as shown in Figures 5 and 6. Figure 12: Photograph showing the attachment sink under the ground plane below the deck with bolts. The BNC I / O models for printed circuit, as also shown in Figure 6.
probe load of 15 W EN1637 A probe load, what for?
It is not easy to find commercially non-inductive resistance of 52 ohms power, or whether to settle a transmitter output stage, we need to apply the output load fictitious (that is, not radiant, purely resistive). Remember that 50 or 52 ohms is the standard value of impedance characteristic of coaxial cables used to attack the transmitting antennas. The other normalized value, rather used for cable reception is 75 ohms. As we wanted to give you the choice of the characteristic impedance of coaxial cable you use to feed your dipole antenna (see Figure 15), we will easily allow you to select the impedance of your dummy load (52 or 75 ohms) as a function of the coaxial cable that you will eventually. Very simply, because the version 75 ohms is obtained by 3 resistors in less amount (that tell you how it will be easy to pass from one version to another two shots soldering iron, just six strokes!). Indeed, we have solved the problem of availability of power resistors anti-inductive 52 ohm or 75 ohm amount in 9 or 6 parallel resistance of 470 ohm 2 W. powers and thus add to our load of 52 ohms will dissipate
9 x 2 = 18 W
and the 75 ohm 6 x 2 = 12 W
therefore, in settings once you feel that resistance heat, you turn the amplifier off and wait for the group of resistors parallel cooling (especially in 75 ohms), you can also consider breaking down your load with a small fan axial or tangential.
professional expenses are immersed in special oil and bogus includes cooling fins, but they are quite expensive and do not use a simple meter to adjust the trimmers of the amp (you must use a RF power meter, the most famous is the famous Bird 43).
By choosing resistors of 470 ohms 2 W, inexpensive and mounting them in parallel, we obtain a total resistance from
which is perfect for 52 ohms and
which is not bad at all for 75 ohms, especially given the tolerances of such resistance.
As shown in the wiring diagram in Figure 2, after rising 9 or 6 parallel resistance of 470 ohms 2 W we have mounted in series in one the two branches of their group with a diode DS1 (1N4150 or 1N4148), this type of diode is capable of straightening up to 150 MHz RF signals and a maximum power of about 25 to 30 W.
The rectified voltage is filtered by DS1 C1-C2, before being measured by a multimeter (Size 50 VDC) passes through the choke JAF1, which all pass filter residue of HF to this meter. At the exit
P = (U x U): (R + R). If, for example, with a load of 52 ohms, we read a voltage of 38 V on the meter at the end of adjustable tuning capacitors, we have a power output of:
(38 x 38 ): (52 + 52) = 13.88 W.
But this is a theoretical power because DS1 introduces a voltage drop of about 0.65 V and the resistance heated, the value of the load from 52 to 50 ohms, the actual power is So in fact:
If, for example, we have an RF power amplifier to deliver 15 W with a load resistance of 52 ohms, we should read the meter:
But in practice we will read a lower voltage of 0.65 V due to voltage drop in DS1.
At the output of a RF output stage 15 W, if we put a load resistor of 78 ohms, we read on the meter voltage:
Again, the voltage actually read is less than 0.65 V
If you chose a load resistance of 52 ohms, then climb the 9 resistors of 470 ohms into two layers, one resistances of 5 and the other 4 resistors.
Between the two layers, leave a space of one or two millimeters (but not more because you would increase the inductive component of the total) for ventilation.
Latest advice To connect the input of your sensor output load of the linear amplifier, use pieces of copper wire tight. At the end of the probe, use the probes R / N on your multimeter set to a size VDC (DC), 50 V or more.
Figure 13: To adjust the two trimmers, you will first need to construct the probe load EN1637 (see Figures 16, 17 and 18) of 52 or 75 ohms. When connected as shown in the figure (the polarity: red hot signal wire, black wire ground), feed the line with a voltage 12 to 15 V. Then connect your FM exciter EN1619 (or another, provided that its output does not exceed 300 mW) feed it. Slowly turn the C3 axis (with a screwdriver HF preferably, that is to say plastic with or without steel edge) to read on the meter maximum voltage, turn the axis of C13 to obtain gauge maximum (of the order of V 25-30-35) You can slightly alter C3, C13 and again, always read on the meter maximum voltage.
Figure 14: BNC input (left) use the output of the exciter FM EN1619 and BNC output (right) from the coaxial cable to the dipole antenna, as shown in Figure 15 (for details, see Figure 4a).
Figure 15: The transmitting antenna easiest to build is the half-wave dipole. It consists of two parts of equal length (73 cm) attacked, one by the shielding braid of the coaxial cable and the other by the soul of the coaxial cable. One can, as in the figure, use copper wire 1 mm in diameter or larger, single or multi-strand flexible (no need to remove the plastic or ceramic sheath, except for welding the ends) and three insulators insulating material (nylon, Teflon, Plexiglas, Lexan, etc.).. In this case the external insulator can have a length of 10 centimeters and the center will allow the two son a space of two centimeters (then drill two holes an inch apart). But you may prefer to make the rigid dipole, this will allow you to place it in vertical or horizontal polarization and direct it towards the area where is the receiver you want to achieve. In this case, take the aluminum tube 5 to 10 mm (there are lengths of a meter that you shrink to 73 cm) and drill in a block of nylon or Teflon or Plexiglas ... a through hole of the hole diameter and a larger diameter (15 or 20 mm) at 90 ° of the preceding and ending in the previous (two holes will form a T), then cut this piece into two symmetrical parts by a plane passing through the axes of holes, you now have two half shells in one have two small diameter tubes, leaving a space of two centimeters and crimp two pop rivets copper on which you solder the core and the braid of the coaxial cable (the latter comes from the larger diameter hole through an aluminum tube of 80 centimeters in length for securing the dipole to its mast and support, with a double jaw at 90 °) that you just coat the inside of the two half shells of epoxy glue and put everything in a press for a few hours (you get something that looks like a T of 1.50 meters by 0.80 meters), set it high enough to have a good clearance to surrounding obstacles (if you're the dipole in vertical polarization, place the wire connected to the braid down) and if you want a light directivity (gain in the direction of the radiating portion relative to the mast) you can fix the retaining tube 15 or 20 mm aluminum tube of 80.5 cm (regardless of its diameter) parallel to the radiating dipole and 73 cm of it (no need to isolate this new tube support tube). You've built something that looks like a large TV antenna or a cross of Lorraine. Note: the characteristic impedance of a dipole of this type is about 75 ohms and if we place the possible reflector (the name of the tube of 80.5 cm) to one quarter of wave (L / 4, or 73 cm) away from the radiator (the name of the radiant tube twice 73 cm) this impedance is not changed.
Figure 16: Photograph of a prototype sensor load EN1637 to dissipate RF power of about 15 W. This replaces the dummy load antenna during the adjustment phase. In addition, it rectifies the RF voltage and draws a DC voltage whose amplitude is proportional to the power supplied by the transmitter and the receiver (using a simple multimeter, then you can simply set the two trimmers for maximum output voltage, as also shown in Figure 13). The 9 resistors of 470 ohms 2 W which are are in parallel, with two lateral tracks of the PCB. This is an impedance of approximately 52 ohms. If you prefer then use a 75 ohm coaxial cable to feed the antenna is not mounted as 6, which is about 78 ohms (so the amp is set for this output impedance).
Figure 17: Diagram of the probe charge EN1637 version 52 ohms (9 resistors). For 75 ohms, does that rise 6 (remove three).
Iist R1 ..... 470 R2 ..... 470 R3 ..... 470
R4 ..... 470 R5 ..... 470
R6 ..... 470 R7 ..... 470 for 52 ohms R8 ..... 470 for 52 ohms R9 ..... 470 for 52 ohms C1 ..... 10 nF multilayer
C2 ..... 1 nF multilayer C3 ..... 10 nF multilayer JAF1 ... 10 uH choke
DS1 .... 1N4148
Figure 18a: Schematic implementation of the components of the probe charge EN1637 version 52 ohms (9 resistors). For 75 ohms, does that rise 6 (delete those of the second for better dissipation, see article).
Figure 18b: Drawing scale 1, the printed circuit the platinum probe load EN1637 side seams.
settings is very simple now that you have the right tool, but you should expect a meticulous and patient. You will indeed have to set two trimmers: the C3 input (purple) and the C13 output (yellow) and you will, after setting C3 and C13 for maximum output voltage, back to C3 for editing, then retouch C13 (always for a maximum output voltage) and back to C3, etc.. Remember, if after a few minutes you notice that the block of load resistance heater, turn the amplifier straight off (you can also put off the exciter), but never remove the sensor when the exciter and the amplifier are especially energized. But first things first. On the workbench in your lab, have left to right the exciter EN1619 and diet. Set to the center frequency of 98 MHz if you do not already know about how often you work (you'll get an average setting giving fairly good results in terms of power output over the range 88-108 MHz) and if you know (eg you have noticed a "hole" in the FM band at 95.2 MHz where no station seems to be issued), set the frequency you set the amplifier to optimize the output power on the precise frequency that will be your working frequency. Connect with a short coaxial cable BNC / BNC, the output of the exciter to the input of the linear amplifier. Connect as shown in Figure 13, the output of your linear amplifier to the input of your probe load (which you have chosen the value of impedance as a function of the impedance characteristic you want to choose for coaxial cable output to the antenna, see Figure 15) with son two very short.
Connect the output of your sensor probes to load the meter with its crocodile clips. For connecting the amplifier to the probe charge and the probe load meter, you must observe the correct polarity (see Figure 13): You see, the + is high (red son) and mass low (black son). Make sure that the chain is complete and properly prepared and, if so, feed the linear amplifier EN1636 (12 to 15 VDC) and the exciter EN1619.
You get first a low voltage on the meter, do not worry not. Take action (preferably with a screwdriver HF that does not disturb the settings) on the adjustable capacitor C3 (entry) to get the maximum deviation of the voltmeter multimeter set to DC and then act on the adjustable capacitor C13 to obtain the maximum deflection of the meter; back towards C3 and try to improve the result, then return retouch C13 to improve the result, then back to C3, etc.. until the optimum setting (in terms of output voltage) is achieved. And feel free to take breaks to let the load resistors cool (during breaks, cut power amplifier and possibly exciter). Do not disconnect the probe load when you cut power to the amplifier and the exciter uncoupled entry. During the settings, the exciter should not be connected to a source modulating BF (the pure carrier is required). Binding to the antenna Remove the probe load, raise the deck any amp in its case and connect the BNC output to the coaxial cable of 75 ohms or 52 (depending on the impedance of the load you used to run the settings) that will drive the antenna.
To achieve the said antenna, see the box in Figure 15. Reconnect the exciter to the input of the amplifier and, after verifying that the antenna is properly connected and placed high enough to be clear of obstructions near, turn on the amplifier and the exciter.
Listen on FM tuner or a radio carrier (a hush!) In you stalling on the transmission frequency.
You can then connect an audio source (eg a CD or the output of a mixer or blender BF) to input the exciter EN1619 (mono or better in stereo) and listen to the post the result.
Then, with a post-cell portable or car radio, you can go to the neighborhood you account for the increase in the scope of your ... FM broadcasting station.
is what you just created and now you can cover several kilometers in radius (this is highly dependent on the size of the chosen frequency and the release of the transmitting antenna, it is certain that a high point like a hill or a water tower, here is ideal, but it became very difficult to find one that is not already occupied by a mobile telephone relay). Finally, remember that in France this type of activity is required to obtain permits and allocation of frequencies by the legislature.
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