The Half Square Antenna: Low-Profile DX Wire for HF Bands

The Half Square Antenna: Low-Profile DX Wire for HF Bands: Build Half Square antenna — a stealthy, no-radial wire delivers ~3 dB gain over a dipole and matches directly to 50-ohm coax. Dimensions for HF bands included.

W3DZZ Multi-Band Antenna 80m-10m Trapped Dipole

Build a Classic Multi-Band HF Antenna!

Discover the W3DZZ Multi-Band Trapped Dipole covering 80m to 10m in this detailed guide from DXR Electronics Bits. Learn how this legendary antenna uses 7 MHz traps to electrically divide the dipole, allowing efficient operation across multiple HF bands with a single wire. The article explains trap construction, antenna dimensions, tuning tips, and installation advice, making it a great DIY project for amateur radio operators who want reliable multiband performance without complex tuners.

🔧 Perfect for hams looking for a compact, efficient, and time-tested HF antenna design.

👉 Read the full guide: https://vu3dxr.in/w3dzz-multi-band-antenna-80m-10m-trapped-dipole/

Getting Started with AIS: Track Ships from Your Shack with a RTL-SDR

Getting Started with AIS: Track Ships from Your Shack with a RTL-SDR: The Automatic Identification System (AIS) is a VHF radio-based collision-avoidance protocol that virtually every commercial, passenger, and large recreational vessel in the world is required to carry. Since 2004, the International Maritime Organization (IMO) has mandated AIS transponders on all ships of 300 GT or more engaged in international voyages, all cargo ships of 500 GT or more on domestic routes, and all passenger ships regardless of size.

Microphone compressor using two transistors

Microphone compressor using two transistors: This microphone compressor circuit utilizes a two-stage amplification design for dynamic range control. Initially, the input signal enters through MK1, a microphone input connector. Subsequently, the signal passes through C1 and C3 coupling capacitors for DC blocking.