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3 W Broadband Amplifier For UHF TV Transposers 2008-03-07 11:15:37 A broadband linear amplifier design is presented, suitable for application in TV transposers, operating in band IV and V(470 - 860) MHz. The design is based on a BLW898 bipolar transistor. Typical results at the recommended class-A biaspoint (25 V/1.1 A) for the total module include a 3-tone IMD level of -64 dB (fvision = -8 dB, fsideband = -16 dB and fsound = -10 dB) and an average gain of 10.5 dB at 3 W peak-sync output power in the (470 - 860) MHz frequencyrange.The BLW898 is a bipolar linear power transistor designed to operate in the (470 - 860) MHz range. The transistor isencapsulated in a SOT171A 6-lead rectangular flange package with a ceramic cap. The specified output power is 3 W peak-sync in class-A. The intermodulation distortion level (IMD) < -63 dB (fvision = -8 dB, fsideband Read more:Amplifier
Microwave Homemade Outdoor Antenna 2.4 GHz 2008-03-05 22:48:52 DimensioningThe very first point in antenna dimensioning is to calculate the wavelength (the Lambda character has been replaced with letter L ):L /mm = 300 / (f/GHz) at 2.45 GHz L = 122 mm.Antenna
picture without mast fasteners: Main parts can been found even in mama's dish cabinet but maybe safer to buy them from a department store. The Reflector is made from an aluminium cake pan and the Cover from a plastic microwave bulb, both 240--250 mm dia. The pan must be straight and smooth without profilations and the sides will be orthogonal with the bottom. If you find a pan made from stainless steel may be that may be better. I used a pan from italo ottinetti code 140024 , whose sides were 60 mm and I cut them to 32 mm.Other parts needed:A piece of copper water conduit, internal dia 10 mm,
FET Audio Limiter 2008-02-18 10:34:23 This applicationis a very high specification peak control limiter. It has fast become the essential deviation limiter for FM radioThe application divided into two parts :Broadband LimiterSplitband LimiterActive component : FET 2N5457 and Ics NE5534, 2N5532, TL071 TL072.Download schematic and component mounted in Coreldraw 12 Format. Read more:Audio
Wideband Amplifer 470-860 MHz For TV Transmitter 2008-02-18 10:22:49 INTRODUCTION The construction taken from the application report NCO8101 two amplifiers for band 4/5 with BLV57 transistors have been described. Reactions on this report proved the necessity to give more information about the construction of these amplifiers. This construction has been based on a heatsink with a printed-circuit board at the upper side and the bias circuits and a forced air-cooling at the lower side. (download datasheet for schematic and instruction)PRINTED CIRCUIT BOARD In the printed-circuit board rectangular holes have been made to mount the BLV57 transistors on the heatsink. For fastening of the printed-circuit board on the heatsink by means of screws, 7 holes of 3.1 mm Æ and for fastening of the hybrid couplers 8 holes of 2.6 mm Æ have been made on the indicated place Read more:Transmitter
, Wideband
BLV859 UHF Linear Push Pull Power Amplifier 2008-02-18 10:21:20 A broadband linear amplifier design is presented, suitable for application in TV transposers operating in band IV and V (470 to 860 MHz). The design is based on two BLV859 bipolar transistorscombined with quadrature hybrids. Typical results at the recommended class-A bias point (25.5 V/9.1 A) for the total module include 40 W peak sync output power at -54 dB three tone IMD level (fvision = -8 dB, fsound = -10 dB, fsideband = -16 dB) and an average gain of 10.5 dB in the (470 to 860) MHz range.The BLV859 is a bipolar linear push-pull power transistor designed to operate in the 460 to 860 MHz range. With a specified output power of 20 W peak-sync in class-A it is the largest device in the new generation of transposer transistors. The intermodulation distortion level is < -54 dB (fvision = -8 Read more:Power Amplifier
, Linear
, Amplifier
100 Watts UHF Band IV-V TV Power Amplifier 2008-02-06 20:33:20 The TV amplifier has been tuned under class-A small-signal conditions and characterised under large signal class-AB conditions from band IV - V in UHF. (All Datasheets)Amplifier
Circuit The total description of the amplifier is given in Figs 6 and 7 and Table 8 (in datasheet). The amplifiers input and output matching networks contain mixed microstrip-lumped elements networks to transform the terminal impedance levels to approx. 25 W balanced. The remaining transformation to 50 W unbalanced is obtained by 1 : 2 balun transformers. The baluns B1 and B2 are 25 W semi-rigid coax cables with an electrical length of 45° at midband and a diameter of 1.8 mm, soldered over the whole length on top of microstrip lines. To keep the circuit in balance two stubs L1 and L8 with the same length have been Read more:Power Amplifier
, Watts
Microwave Power Meter 2008-02-03 22:25:06 Article from Hans Wagemans, ON4CDU A sensitive power meter is a very useful instrument when doing experiments. A few years ago when I started my microwave radio hobby up again, the first project I undertook was building a 23 cm transverter. During the development, a diode in front of my analog meter (VOM) was used to tune the microwave circuits to the resonance frequency. During the experiments, the need for a more sensitive and precise power meter was recognised. After some experiments it turned out that, based on the principle of the diode rectifier with a cheap amplifier behind it, a simple, but also sensitive and accurate power meter could be built. The circuitThe input circuit consists of a 'wide dynamic range' RF diode detector. This 'wide dynamic range' is obtained by applying a bia Read more:Meter
Oxygen FM Manager 2008-01-31 05:07:40 Oxygen FM Manager is designed to give you full control over Nokia phones FM Radio. Load FM station presets from the phone to the PC's memory, easily edit them and upload back with just couple of clicks. Create custom FM presets, save them on disk and send them to the phone anytime you want. Oxygen FM Manager grants access to the Oxygen Online FM Stations Library that contains information about FM stations in cities all over the world.Compatibility :Program supports the following phones: Nokia 2255, 2300, 2355, 2855, 2855i, 3152, 3155, 3155i, 3200, 3205, 3300, 5100, 5140, 5140i, 6030, 6070, 6101, 6102, 6103, 6111, 6112, 6125, 6126, 6131, 6133, 6136, 6151, 6155, 6155i, 6165, 6165i, 6175i, 6200, 6220, 6225, 6230, 6230i, 6233, 6234, 6235, 6235i, 6236i, 6255, 6256, 6265, 6265i, 6268, 6270, 6275 Read more:Oxygen
14 Watts UHF TV RF Amplifier 2008-01-27 11:53:02 This amplifier work in frequency 470 - 860 MHz Band IV DAN V with power out 14 Watts
with input power 1.5 Watts. SchematicPart Lists:C1 = C6 = C16 = 4,7 pF (500 V) multilayer ceramic chip capacitorC2 = C3 = C20 = C21 = 33 pF multilayer ceramic chip capacitorC4 = C9 = C13 = C19 = 1,2 to 3,5 pF film dielectric trimmerC5 = C7 = C15 = C17 = 100 nF multilayer ceramic chip capacitorC8 = C10 = C11 = C12 = 220 pF multilayer ceramic chip capacitorC14 = C18 = 6,8 mF/40 V solid aluminium electrolytic capacitorC22 = C23 = 1 pF (500 V) multilayer ceramic chip capacitorL1 = L2 = L13 = L14 = Coax. 50 Ohm with diameter 2,2 mm; lenght 29,0 mm, soldered on striplines75 W (1,1 mm ´ 28,0 mm). inner L1 dan L13 not connectedL3 = L4 = 52 W stripline (2,0 mm ´ 16,5 mm)L5 = L8 = 470 nH microchokeL6 = L7 = 39 W s Read more:Amplifier
100mW VHF TV Transmitter #1 2008-01-27 11:14:40 For many years, various electronic newspapers on many aspects of audio radio production, and radio and television signals on the production of not too many, a very important factor is the launch of TV signals than the production of audio radio more difficult to bigger. Forum on the recent request for easy system and television signal transmission devices voices high, in order to meet the requirements of enthusiasts, the time to test this television transmitters. The circuit design guiding ideology is not any RF equipment will be debugging, performance professional equipment Although it is impossible to achieve the target, but its basic properties should be able to meet lovers experiment, audio-visual transmission effect should not be inferior to the universal-type machines level.The trans Read more:Transmitter
100mW VHF TV Transmitter #2 2008-01-27 11:03:24 Practice ChapterThe 100 mW transmitter board after the completion, we have to find a friend five students to experiment, to do a one-person, mainly through practice to check this board to the production of difficulty.Experimenters are not voluntary and not the whole experience in the production of electronic technology-loving, we will of this board divided into several steps to do.The first step Modulation of the installation, the following components in the circuit welding good. 1. TA7673 11 feet measured voltage is 3.8 V should be about.２．TV will be the input RF (antenna port) between the RF modulator output, TV should be able to receive RF signals, the screen showed very pure white grating. Note: I should be separated from direct antenna function, and if not should be connected in s Read more:Transmitter
FM Transmitter 300 Watt 2008-01-27 06:51:45 This FM Transmitter
generates frequency 88-108 MHz by PIC PLL Program and built in oversampling Stereo Encoder (PIC Program) with LM13700 limiter audio. In manual book, transmitter amplified with one Mosfet Transistor. This Transmitter produced by broadcastwarehouse.In construction, FM Transmitter divided into three blocks :1. Audio Processing (Limiter + Oversample Stereo Encoder) BlockLimiter is a standard of audio processing in transmitter block. It limits the audio input level to stereo encoder. LM13700 Chip from National used as Variable Control Audio.2. RF Generator (VCO+ PIC PLL) BlockVCO (variable control oscillator) generates a range of working frequency 88-108 MHz controlled by PIC Phase Locked Loop.3. Amplifier and Filter Block.This block amplify signal from 1 Watt from PLL Exci
Simple RF Amplifier Protector Circuit 2008-01-18 04:56:00 This circuit protector is so simple, but it has big function in protecting your rf amplifier device. The input part signals for protecting are :Termo Switch (Heat Sensor Resistance) from your active component, RF Power transistor/FET.Forward and Reflect (reverse) from your directional coupler after your Low Pass Filter Output.Over Drive from directional coupler at the input of your rf amplifier to limit power input in normal condition.Relay (12v DC) for disconnecting power supply of your RF amplifier if condition for protecting happened.Attention :Do it manually before you install it in real condition. Don't forget to adjust 50K resistor for every input parts. Read more:Circuit
, Simple
, Amplifier
CONVERT AV TO VHF TV RF Signal 2008-01-16 21:58:54 Small Circuit to send your Audio Video from DVD player or satellite receiver to VHF RF signal. This circuit connected to TV RF input via 75 ohm cable or telescopic antenna. Don’t use this circuit for more power without filter and use antenna only to transmit. Frequency range on vhf band about 50-250 MHz.You can change the transistor for transmitting on UHF band. Keep the components lead shortly. Recommended use crystal or PLL technic for stability of frequency.
How To Stack Your Antenna On FM Broadcast Band 2008-01-14 05:31:39 Stacking your broadcast antenna will make your antenna have more gain. If your antenna have more gain, more ERP (Emmittion Radiating Power).What do you need for stacking antenna?- More antennas that identical each others.- Power divider to distribute your RF power to each antenna.- Jumper cables to connect antennasFor Stacking 4 Antenna
Antenna : prepare 4 identical antenna. Tune the antenna for Matching on the working frequency.Power Divider : prepare 1 power divider with 1 port input and 4 ports output. Jumper Cables : any length of coax cable with 2 N connectors to connect between power divider and antennas.Determinate Range between Antennas • When you install the antennas in collinear system, you must observe the distant “D” (see drawing of follow page) between two antennas. The Read more:Broadcast
, Stack
MRF317 FM Amplifier 88-108 MHz 2008-01-13 03:56:00 FM amplifier is used for amplify signal from exciter in broadcast radio station. In this page, RF FM Amplifier
uses solid state material with minimum gain 9dB. Input FM Amplifier needs 5-10 watt with power output about 100 watt. The Block schematic and datasheet
FM LowPass Filter For 88-108 MHz 2008-01-13 03:54:20 Filter used for eliminate unwanted harmonic frequency at second and third. Notch filter, Band Pass Filter, and High Pass Filter sometime combined in constructing LPF design. Schematic below for FM Broadcast Lowpass Filter 88-108 MHz. It has tested with good result.Note : Make the coils at 74 nH and trim them to adjust exact value. Read more:Filter
Power Electronics Tutorial 2008-01-13 00:41:39 Interactive Power Electronics Online TextOnline course that includes diode circuits, fully controlled 1-phase and 3-phase bridge rectifiers, semi-controlled rectifier circuits, and switch mode power supply.Florida Power Electronics CenterA power electronics research and development center at the University of Central Florida. Publications archive, courses notes, links.Power Electronics GroupPower Electronics Group of Ben-Gurion University. SPICE models downloads, tutorials, papers and theses.Electrical Machines and Power ElectronicsResearch in power electronics, electrical machines and drives. Contains abstracts of theses and papers.3M Electronics ManufacturingManufactures materials and components for PCB manufacturing and assembly, semiconductor manufacturing and electronics products. Onl Read more:Tutorial
Satellite Antenna Alignment v2.38.0 2008-01-11 06:45:19 The program "SatelliteAntennaAlignment
" is used to calculate the angles necessary for installing satellite dishes. The main difference from similar software is the possibility to calculate the position for all satellites at once. Thus, you get a clear picture about what satellites can be physically visible from the location where the dish will be installed. Additionally, the program has a mechanism for calculating the azimuth of the sun and you can do everything without a compass now! Windows VistaLicense: Freeware Size: 988 Kb DownloadPlatform: Windows XP, Windows NT, Windows Me, Windows 98, Windows 95, Windows 2003, Windows 2000 , Windows VistaKeywords : Satellite - Dish - Antenna - Alignment - Sat-Satellite Dish - Satellite Dish Descrambler - Form Alignment - Dish Tv - Dish Network -
ALDEMURA The Basic Path Loss SOFWARE FOR FREE 2008-01-09 20:11:04 A forecast model allows to avoid long and expensive measure campaigns.An efficient forecast model represents a valid tool to obtain attenuation estimates.Okumura's model was developed using measurement data taken at several frequencies in the Tokyo urban and suburban area.This method is most appropriate for urbanized areas where the study distance is relatively short (less than 30 km), the effective transmit antenna height is less than 200 meters, the effective receive antenna height is less than 10 meters, and the terrain is relatively flat. Download ALDEMURA 1.8 Mb from ALDENAIn 1980 Masaharu Hata simplified the consideration from Okumura (Empirical formula for propagation loss in Land Mobile Radio Services).These simplifications led to the restriction that only region with less than 20 Read more:Basic
VHF TV Transmitter Band I 2008-01-05 23:44:15 Need to try building this old schematic! I take this schematic from my chinese friend in 1992. This TV Transmitter
works in VHF TV Band I and you need crystal for generate the frequency. The final amplifier uses one 2SC1971 and 2SC2053 as buffer/driver stage. If you are creative, you should change crystal with PLL oscillator. Below is UHF VCO for Wideband 470-860 MHz.
FM Broadcast Antenna 88-108 MHz 2008-01-05 23:21:40 IntroductionAntenna
is final device for sending any information from your transmitter. In fm transmitter you need signal transmitted to any direction so you need antenna type that transmitted with polarized circularly. Gain Antenna -3.2 dB, bandwith 500 KHz with maximum power handling 500 Watts. In order to use antenna on 88-108 MHz, broadband antenna type must be designed with no tune involved.How Your Signal AmplifiedAmplification of signal to transmit based on antenna gain in Decible. Signal from transmitter be able to doubled, tripled or even become more power. The value is called ERP (Emmittion Radiating Power). For Doubled your transmitter power to be ERP Power need stacked 4 antennas (3.12 dB gain antenna), 6 antennas (5.12 dB), 8 antennas (6.4 dB).ERP = Transmitter Power x Antenna Read more:Broadcast
TV RF Amplifier 470-860 MHz 2008-01-04 16:30:41 TV Linear Power Amplifier
for 470-860 MHz taken from Philips Aplication Note (AN_BLW32_33). Please download file in PDF format.The Wide-Band UHF Power Amplifier for TV Transposer band IV/V designed with transistor BLW32 and BLW33. In this case, my RF Amplifier design replaced them with 2 pieces BLW34 have good result. For combine two BLW34 download file here
Two ports 2.4 GHz RF Power Divider-Combiner 2007-12-26 10:56:30 This Power Divider Combiner not only use for dividing or combining RF power on RF amplifier constructions, but also use in dividing RF power if you use more than one antenna for higher gain.The Construction of simple power divider combiner with the equation below : Z = 1.38 x log (1.08 x (D/d)) for square tube Where, D = The Inner Width of the tube d = The Outer Diameter (OD) of the inner conductor Z = Impedance The Equation of Impedance Approach : Z = 1.38 x log (1.08 x (D/d)) Z = 35.88 Ohms A = Chasis mount N Jacks B = Solder the N center connectors pins directly to the inner of the copper conductor C = 12.7 mm (1/2 inch) outer diameter (OD) copper conductor D = 25.4 mm (1 inch) square aluminium tube, with wall tickness of 2 mm For ¼ wave power divider, the impedance theoritical needs Read more:ports
Attenuator Design Tutorial 2007-12-23 13:52:36 IntroductionAttenuators are devices used to adjust signal levels, to control impedance mismatch and to isolate circuit stages.Passive designPassive attenuators consist of two types ‘pi’ and ‘Tee’ attenuators.1. Pi AttenuatorThe circuit for the Pi attenuator is shown in Figure 1. 2. Tee Attenuator The circuit for the T attenuator is shown in Figure 2 3. Bridged T AttenuatorThe circuit of the bridge T attenuator is shown in Figure 3 This circuit is commonly used with PIN diodes to form an electronic attenuator, as only two variable resistors are required (instead of 3 for the Pi or T attenuators). Read more:Tutorial
1W Linear Power Amplifier 2.4 GHz 2008-03-12 17:39:25 The following single-stage transistor linear amplifier possesses a gain of approximately 7 dB and an output power of 1 W in the 13 cm band (approx. 2.4 GHz). It is thus suitable for use, for instance, together with the 13 cm transmit converter. This hybrid power mixer equipped with a varactor diode type BXY. This mean that the described power amplifier can provide linear output power in the order of 1 W.CIRCUIT DESCRIPTIONA transistor type F1E6 manufactured by CTC is used. In this case of this transistor, the emitter is internally connected to the cooling bolt. This ensures that there are no problems with respect to the high-frequency grounding of the emitter. The circuit diagram of this amplifier is given in figure 1. The matching of the transistor input and ouput impedance to 50 Ohm is Read more:Linear
, Amplifier
UHF VHF PLL TV EXCITER MC44BS374TI 2008-03-09 04:41:00 This UHF VHF PLL TV TRANSMITTER use a MC44BS374TI from Freescale. MC44BS374 is audio and video modulator for use in Transmit Video and audio and similar device. These IC are the next generation of the MC44BC374TI with the following new features :- TV output level 83dBuV- 5V and 3.3V compatible I2C bus- Logic Output Port pin (pin 3) availableMC44BS374 IS a PAL/NTSC Modulator with Integrated VCOThe channel is set by an on-chip high-speed I2C compatible bus receiver. A Phase-Locked Loop (PLL)tunes the modulator over the full UHF range.The modulator incorporates a sound subcarrier oscillator and uses a second PLL to derive 4.5, 5.5, 6.0,and 6.5 MHz subcarrier frequencies. These frequencies are selectable by bus.The picture-to-sound ratio may be adjusted using the bus. In addition, an on-chip v
BH1415F FM Stereo PLL Transmitter 2008-03-09 03:45:55 This is FM PLL Stereo
based BH1415F IC from Rohm, it's has built in PLL and Stereo Encoder. You can download the schematic, pcb layout and Hex code. The transmitter menu display with LCD, and this have step 100Khz, 200Khz,.....1000Khz and have Mode menu (stereo/mono). In Action, LCD Display can solder directly on the bottom.Download : schematic, PCB all layer, top layer, bottom layer, hex codeBuy all components for this application here Read more:Transmitter
Understanding TV Modulators 2008-03-14 12:09:30 INTRODUCTIONThe Modulator is an indispensable part of any Headend or control room. Most CATV technicians accept the use of Modulators and the fact that each channel requires a Modulator at the Headend. However often, details of why modulation is necessary to beginwith or the differences between various Modulators topology such as Saw Filter, single PLL, Double PLL and Frequency Agile Modulators, is often not fully understood. This article sets out to address these matters, in simple, easy to understand language.MODULATIONWhile we all understand that a Modulator is required to modulate each channel at the CATV Headend, why do we need tomodulate ? If we were to pass a single RF signal on a Cable TV network, the coaxial cable is well suited for the application. However, even one channel actu Read more:Understanding
TV Modulator Circuit 2008-03-13 13:48:08 The MC1374 includes an FM audio modulator, sound carrier oscillator, RF oscillator, and RF dual input modulator. It is designed to generate a TV signal from audio and video inputs. This TV modulator based MC1374 IC From Motorola with wide dynamic range and low distortion audio make it particularly well suited for applications such as video tape recorders, video disc players, TV games and subscription decoders.The IC features:Single Supply, 5.0 V to 12 VChannel 3 or 4 OperationVariable Gain RF ModulatorWide Dynamic RangeLow Intermodulation DistortionPositive or Negative SyncLow Audio DistortionFew External ComponentsFor more info download datasheet - application note Read more:Circuit
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