Saturday, May 14, 2011 by Rangkaian Elektronika
Radio communication transceiver is a radio transmitter at the same time the plane doubles as a radio receiver used for communication purposes.
It consists of the transmitter and the receiver are assembled in an integrated way. In mulamula generation, the transmitter or receiver or transmitter and receiver sections are assembled separately and is part of a stand sendirisendiri and can work well sendirisendiri Currently employed both parts are integrated in turn.
Aircraft simple transmitter consists of an oscillator generating radio vibration and this vibration after vibration boarded with our voice, in a technique called dimodulir radio, then by the antenna is converted into radio waves and transmitted. As we know that the sound waves we can not reach long distances, although its power is quite large, while the radio waves with a relatively small force can reach a distance of thousands of kilometers. In order for our voice can reach a far distance, then our voice superimposed on radio wave radio results from the vibration generator, called a carrier wave or carrier and the carrier wave was going to deliver our voice to distant places.
In a place far earlier, the radio waves emitted by the antenna received our speaker. By the antenna, radio waves had, in the form of electromagnetic waves is converted into electrical vibrations and into the receiver.
In our speaker receiver plane, vibration and vibration carriernya then discarded and then raised our voices be accommodated through the speakers. With this technique it is possible modilasi an audio vibrations reach a far range.
We sound vibrations enter the transmitter through a microphone, microphone output was often needs to be strengthened first with an audio amplifier is called a microphone preamplifier can be superimposed on the carrier for the modulator.
To increase the transmission power of a transmitter, vibration of the oscillator was before the emitted amplified first with a radio frequncy amplifier. Strengthening can be done once and can also be done more than once. Transmitter is not reinforced is called a level transmitter and the reinforced one called two-level and beyond. In general, to reach 100 Watt transmit power need to strengthen the 3 times, the first amplifier is called predriver, the next amplifier called the driver and final amplifier called the final amplifier.
Block Diagram of SSB Transceiver
If we're talking about the Single Side Band, then we touched more on amplitude modulation (AM). At each modulation we do we actually do the mixing between the radio frequency to audio frequency. Any mixing of two frequencies will occur the second summation process and at the same frequency reduction process occurs from both frequencies.
So every time we memodulir carrier, will produce two frequencies at once. For example, a carrier with a frequency of 3000 Kc we modulir with audio ferkuensi 3 Kc, the result is 3003 Kc and Kc 2997, or said occurred two sides of the band is the upper side and lower side. The top side and bottom side are shaped symetris, so if it is a direct result of modulation we mean we memancarakan exude the same two goods.
If we shine the way mentioned above, we use the mode is said to Double Side Band (DSB) because the carrier that includes top and bottom sides are emitted together. In factory-made plane, this mode is usually coded in terms actual AM radio is the DSB technique.
We know there are two kinds of ways to make the SSB, the first way is by phase shift method, another way is by filtering methods. The first way is not widely used and factory-made aircraft SSB generally use filtering.
Signal DSBSC, before the amplified and transmitted, is inserted into the SSB filter in advance to produce LSB or USB. Filters are used for this purpose is filtering crystal or mechanical filters. SSB transmitter is said to be more efficient than AM (DSB), we can give this picture as follows. For example transmitter AM (DSB) with power 150 Watt (100% modulation depth), then power on the USB and LSB respectively and the carrier has a 25 Watt 100 Watt power. We know that the audio side we are on the band. In the SSB emission, emitted only one side band LSB or USB is a powernya only 25 Watt.
With SSB 25 Watt beam, the audio we have to arrive at destination with the same clarity of information with jet AM (DSB) 150 Watt earlier.
Another advantage of SSB is the wide-band mode that can be more narrow. For the purposes of communication, SSB mode requires only the band width of about 3 Kc, while the DSB mode takes about 6 Kc, thus providing savings SSB mode the use of the band.
In the detector a SSB receiver, the received signal must be mixed in advance with the frequency of the outcome of a Beat Frequency Oscillator (BFO) and used as the BFO carrier oscillator.
Homebrew QRP SSB Transceiver circuit 80m Band
In general, the transceiver has the following block diagram, basically Transceiver tebagi into three main parts: Part VFO and BFO Part Transmitter (transmitter) and Section Receiver (receiver), where there are some special blocks that are used for both paths are either transmitter or receiver. Simply in this transceiver merkit Use the tools that we only Multi tester, RF Probe, SWR and Power Meter, Tone Generator Af 1Kc and multi-band Radio HF SSB to function as a monitor frequency BFO, VFO, monitor Balanced Modulator Exciter at once both the transmitter or receivers .
Frekwency Range: 3700 Kc a / d 3900 Kc
Mode: LSB Singgle conversi
IF: 455 Kc (Ceramic Filter SFU type 455)
Local oscillator: VFO with Fine Tuning varactor diode
BFO: Ceramic Filter 455 SFU
RF PA: Power FET IRF640, IRF540, IRFZ44
DC: 13.8 V
RF Power: Over 8Watt
The order of assembly sequence of assembling consecutive start BFO, VFO, AF Amp, IF amplifier and detector products to filter amplifier circuit, Mic Amplifier, Balanced modulator, RX mixer + Rf amplifier, mixer TX last order to facilitate the checking of each unit due to series This is a merger of several units of its own circuit.
Memprgunakan SFU type ceramic filters used 455 two-foot middle leg to ground is coupled with capacitor and capacitor trimer and one leg edges to the base of the transistor, BFO uses two types of 2SC1815 transistors. Tc 1 to set the BFO on 453.5Kc frekwensy being black 455Kc IF transformer to regulate the level rather than BFO. To check this The set uses RF Probe. At the secondary BFO output T9 check with RF probe set T9 smpai maximum output level monitor in the radio frequency or HF trimer and Counter set Capacitor capacitor pararelnya until fulfilled the required frequency of 453.5Kc. To check whether there are oscillations in the BFO off Ceramik filter whether RF probe was still moving when he checks it again rangakain ceramik here if we filter out the RF probe is not moving.
For we use the VFO FET 2SK192 Type and reinforced with a single fruit type transistor 2SC1815. Raft of this series as neat munkin with component selection, especially capacitor here we use a paper capacitor in series of Colpits oscillator. Close this series with a metal box along with all Varconya. VFO same testing with the BFO circuit Trime Koker Ferrite T13 dapakan frequency monitor the frequency of 4100 Kc s / d 4300 Kc obtained in case of no frequency range is set set the number of coil and capacitor values bypas to groundnya.
AF Amplifier IC type LM386 used raft this section and check out by Spiker at putnya. Plug the foot of its inputs with a screwdriver had no defects at the time vulume potensio enlarged.
IF AMP AND PRODUCT detector.
Raft had Produc detectornya from starting until the fourth diode 1N60 IF transformer T7 455 black color until the transformer bypass capacitor to ground. Plug one side of the transformer with a screwdriver kai harden the audio volume on the speakers should be no reaction. Attach the amplifier transistor for testing at its base on the speaker should be louder voice. Raft this section everything.
Put all the components properly to eighth ceramic filter installed all. Just listen to the speaker plug on the input or pairs if a small number of meters of cable serves as an antenna trim T6 and T8 listen to the voice on the speaker until no defects dispeaker be hissed loudly.
RX MIXER AND RF amplifiers.
This series of rafts with the good and right in making the winding must be in a state of neat. Enter Snyal VFO to try to monitor the input mixer is QSO friends turn ferrite in successive Koker turu of T3 and T4 to get a strong signal reception and set the T1 and T2 ferrite to signal strong receipts received with respect to the level of the S Meter. If that is not found try to check this section further. Thus selesei we've Section Receiver unit.
Raft of this section and replace all the LM 741 IC listen with headphones turn out putnya potensio putnya try out the level of talk in the microphone must be perfect without any defects in the out putnya.
Balanced modulator uses AN612 ic type commonly used on the CB radio. Raft all components correctly. To check this series of pairs of probes to the output at ic AN612 when no signal on the IC probe set trimpot until the deviation of zero and then try to plug in with tweezers pda mic input amplifier should have needle probe deviation. Then plug micropon try talking meter on the probe to move the motion according to your speech input level. Put some small cable length as the antenna you are trying to monitor diradio HF signal here was DSB Uper and Lower Side band sound. Dengarka until there is no defect here is selesei sets. Then go Filter amplifier output to try to talk Rangkian denagan put up some yards kabbel to secondary T6 try IF 455 White color monitor frequency of 455 Kc diradio on and try to talk trim ferrite Ferrite T6 and T8 until you hear the sound on USB diradio no oscillation and no deviation selef the meter on the probe. If on your radio monitors have didapatka perfect sound means you've selesei at once to part If rceifernya.
Raft section make this all too well circumference at T11 and T12 as neat as possible. Mixer that we use the type of premises IC TA7310 2SC1815 transistor amplifier pairs as well. Then plug VFO output and Out put Balnce Modulatornya on laulu TA7310 ic input probe pairs give the mic input with tone generator af ferrite trim T11 and T12 refer to deviation meter probe to obtain the largest deviation meter. Put microppon try talking dimicropon deviation meter see if we're not talking micropon but no deviation on the meter needle probe set trim T11 and T12 until no deviation in meters try to talk again in micropon deviation meter should move according to their level talks on the microphone. Try installing a few meters of the small wires on the monitor amplifier output tx diradio exciter in accordance with the frequency of our work with the fashion side band LSB if we do not get on the LSB mode with sempurana set again trimer capacitor on the BFO and rotate slightly if T8 transformer ferrite in black color smpai obtained side band we want. Up here seleseilah exciter circuit.
TX PA amplifier.
PA series we take the type of Power FET because it is cheap and easily available in the market. Create a transformer with a good and right not to email pda scuffed pair of wires until there is a first level transistor 2SC1815 output pairs of probes on trying to talk on the microphone deviation at Beh probe must be greater than the level of exciter here should not happen if not self-oscillation oscillation talk there is no deviation on the meter needle probe. In the event of self-oscillation try to check the part. Similarly, the driver assembly. Drivers are taking transistor type 2 SC1162. gained power level meter must be greater than the previous level as well. Then the final units also make coils as neat as possible. Testing out first input of the exciter arur Pa measuring voltage trimpot should not exceed 3V plug out put a probe hyarus no deviation on the meter. In the event of significant deviation occurs in pagian the oscilasi cell. Then plug the input of the exciter ac voltmeter pairs of avo meter try to speak in micropon meter on ac at avo meter should show a few volts ac in accordance with the level of talking on the microphone.
LOW PASS FILTER.
Create a winding low pass filter with a nice and neat L1 and L2. pairs of all components of the relay to properly check penyambunngan pairs dumy 50 Ohm load at the antenna output connector do not forget to SWR and Power meter is installed. Speaking at a microphone set set ferrite Koker L1 and L2 to obtain the maximum and then check SWR poiwer it must appoint 1: 1 with dumy Load 50 ohms if not check again Low Pass filters. After iti try to plug the 80m band antenna connector is on your monitor qrp radio QSO friends who try to enter it and asked for the report