Build A 10 Amp 13.8 Volt Power Supply

Just like other commercial units, this circuit uses the LM723 IC which gives us excellent voltage regulation. The circuit uses 3 pass transistors which must be heat sinked. Resistor R9 allows the fine tuning of the voltage to exactly 13.8 volts and the resistor network formed by resistors R4 through R7 controls the current limiting. The LM723 limits the current when the voltage drop across R5 approaches .7 volts. To reduce costs, most commercial units rely on the HFE of the pass transistors to determine the current limiting. The fault in that system is that the HFE of the pass transistors actually increases when the transistors heat up and risks a thermal runaway condition causing a possible failure of the pass transistors. Because this circuit samples the collector current of the pass transistors, thermal runaway is not a problem in this circuit making it a much more reliable power supply.
The only adjustment required is setting R9 to the desired output voltage of anywhere between 10 and 14 volts. You may use a front panel mounted 1K potentiometer for this purpose if desired. Resistor R1 only enhances temperature stability and can be eliminated if desired by connecting pins 5 and 6 of IC-1 together. Although it really isn't needed due to the type of current limiting circuit used, over voltage protection can be added to the circuit by connecting the circuit of Figure 2 to Vout. The only way over voltage could occur is if transistors Q2 or Q3 were to fail with a collector to emitter short. Although collector to emitter shorts do happen, it is more much more likely that the transistors will open up when they fail. I actually tested this and purposely destroyed several 2N3055's by shorting the emitters to ground. In all cases the transistors opened up and no collector to emitter short occurred in any transistor. In any event, the optional circuit in Figure 2 will give you that extra peace of mind when a very expensive radio is used with the power supply.
The circuit in Figure 2 senses when the voltage exceeds 15 volts and causes the zener diode to conduct. When the zener diode conducts, the gate of the SCR is turned on and causes the SCR to short which blows the 15 amp fuse and shuts off the output voltage. A 2N6399 was used for the SCR in the prototype but any suitable SCR can be used. While over voltage protection is a good idea, it should not be considered a substitute for large heat sinks. I personally feel the best protection from over voltage is the use of large heat sinks and a reliable current limiting circuit. Be sure to use large heat sinks along with heat sink grease for the 2N3055 transistors.
I have used this power supply in my shack for several months on all kinds of transceivers from HF, VHF to UHF with excellent results and absolutely no hum. This power supply will be a welcome addition to your shack and will greatly enhance your knowledge of power supplies.

Parts List
R1 : 1.5K ¼ Watt Resistor (optional, tie pins 6 & 5 of IC1 together if not used.)
R2,R3 : 0.1 Ohm 10 Watt Resistor (Tech America 900-1002)
R4 : 270 Ohm ¼ Watt Resistor
R5 : 680 Ohm ¼ Watt Resistor
R6,R7 : 0.15 Ohm 10 Watt Resistor (Tech America 900-1006)
R8 : 2.7K ¼ Watt Resistor
R9 : 1K Trimmer Potentiometer (RS271-280)
R10 : 3.3K ¼ Watt Resistor
C1,C2,C3,C4 : 4700 Microfarad Electrolytic Capacitor 35 Volt (observe polarity)
C5 : 100 Picofarad Ceramic Disk Capacitor
C6 : 1000 Microfarad Electrolytic Capacitor 25 Volt (observe polarity)
IC1 : LM723 (RS276-1740) Voltage Regulator IC. Socket is recommended.
Q1 : TIP3055T (RS276-2020) NPN Transistor (TO-220 Heat Sink Required)
Q2,Q3 : 2N3055 (RS276-2041) NPN Transistor (Large TO-3 Heat Sink Required)
S1 : Any SPST Toggle Switch
F1 : 3 Amp Fast Blow Fuse
D1-D4 : Full Wave Bridge Rectifier (RS276-1185)
T1 : 18 Volt, 10 Amp Transformer Hammond #165S18 (Digi-Key HM538-ND)

2 Meter Collinear J Pole Antenna Project

Pembuatan Antena ini tidaklah sulit, karena hanya terdiri dari beberapa potong Pipa PVC sebagai penopang dari Element Antena yang terbuat dari pipa Aluminium dia. 3/8".Komponen lain yang berfungsi sebagai penyambung antara element dengan phasing inverted menggunakan Elbow yang sesuai dengan ukuran Pipa.Karena Antena ini cukup panjang, maka sengaja di bagian tengah dipasang " T " socket sebagai dudukan horizontal bracing ke Tower.. hal ini dimaksudkan agar Antena cukup rigid ketika ditiup angin cukup kencang.

FORMULA FOR CALCULATION OF SECTION LENGTHS

Longest bottom Section 8424/freqmhz = inches

Top Section and other sections 5616/freqmhz = inches

Matching Section 2808/freqmhz = inches

EXAMPLE:146mhz

Center frequencyLongest section 8424 / 146 = 57.69 inches

Top section and others 5616 / 146 = 38.45
inchesMatching 2808 / 146 = 19.23 inches

silahkan mencoba,...lumayan lho * 8db

radio Rig 2m band favorite

sedikit bahasan tentang rig 2m band favorite

kita mulai dengan Product Kenwood

KENWOOD TR-9130
VHF (Very High Frequency) transceiver.
Perangkat tua ini mempunyai kelebihan, yaitu RF gain.
RF gain biasanya berguna untuk menyaring sinyal-sinyal yang mengganggu.

RF gain lebih khusus dipergunakan jika antenna yang kita pakai merupakan Yagi Antenna alias antena pengarah. Dimana dengan RF gain kita bisa lebih mengfokus dan mengetahui arah titik asal sumber sinyal radio dari sebuah perangkat komunikasi radio.

Selain RF gain dengan memakai RF Modul original-nya M-57727 Mitsubishi, perangkat ini dapat dipakai berkomunikasi pada USB, LSB, SSB dan CW. M-57727 ini sekarang sangat jarang dijumpai. Informasi terakhir, jika benar bahwa dengan memakai RF Modul lain yang tentunya harus dimodifikasi, maka semua akan berfungsi seperti jika menggunakan M-57727.

Bentuk fisik lumayan besar, tetapi tetap asik jika ditempatkan di mobil.
Power Output 5 watt untuk Low Power, 30 watt untuk High Power adjustable.
Lebar frekwensi yang tidak cukup lebar untuk masa sekarang, cocok untuk band amateur.
Masih diminati sampai sekarang, walau sudah tidak diproduksi sejak tahun 90-an.

kenwood TR 9130

next Radio

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tm 261a

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