over voltage

over voltage

Antennas : Baluns

• A better antenna-tuner balun - Which balun to use? The hybrid balun promises advantages over both voltage and current baluns by ZS1AN
  [ Hits: 23096 | Votes: 11 | Rating: 5.83 ]

• T2FD Antenna - Terminated and twisted folded dipole - T2FD is a 600-900 ohms folded dipole, terminated with resistor. Feed impedance is coupled with 50/600 ohms voltage balun. It is a wide band antenna with rather low SWR over the full designed frequency range: antenna tuner is seldom needed.
  [ Hits: 488 | Votes: 0 | Rating: 0 ]

• Icom 706MK2G Repair - After years of reliable performance, a 26-year-old Icom 706MK2G exhibited an unusual deviation during FM transmission, with the actual frequency being 10kHz off from the displayed frequency. Additionally, the power meter showed a sharp dip during transmission. Upon investigation, it was discovered that the FM VCO voltage adjust variable had become dirty and sluggish over time. By adjusting the variable capacitor and cleaning it with switch cleaner, the issue was resolved, restoring stable power output and accurate frequency transmission.
  [ Hits: 18 | Votes: 0 | Rating: 0 ]

• FT-817 DC Circuit Protection - A schematic for a DX circuit protection for the Yaesu FT-817, provides protection from the external power supply overvoltage by DL2LTO in german
  [ Hits: 1133 | Votes: 1 | Rating: 3 ]

• FT CALC 1.3 - Ferrite Toroidal Core HF Calculator - This EXCEL Program Worksheet calculates the safe operating conditons for a toroidal transformer operating between 1 and 50 MHz. Manufacturer data for complex permeability, magnetic dimensions, and saturation flux density must be available. Some core types which are commonly used in amateur transmission are included. The program produces limiting winding voltages for linear operation and temperature rise over the range of frequencies and power specified.
  [ Hits: 283 | Votes: 1 | Rating: 2 ]

• Building a Robust PL519 Tube HF Amplifier - his article explores the construction of a PL519 tube amplifier, utilizing Ulrich L. Rohde N1UL's insights. Focusing on a modest 25W continuous output, the design ensures robustness with forced air cooling. The detailed breakdown covers input matching, screen grid voltage generation, bias adjustment, anode power supply, heater power supply, and monitoring circuitry, providing valuable guidance for ham radio enthusiasts.
  [ Hits: 71 | Votes: 0 | Rating: 0 ]

• Why grounding - Overvoltage protection, Voltage stabilization, Grounding in wiring, Ground wire resistance
  [ Hits: 1726 | Votes: 1 | Rating: 1 ]

• A Power Supply on the Cheap - Need a variable power supply that is short circuit protected and over voltage protected; Here is a good one that can be built cheap by VE3IVJ
  [ Hits: 2586 | Votes: 0 | Rating: 0 ]