Full Wave Loop Antenna for VHF UHF FM Radio Bands

Looking to upgrade your VHF/UHF setup without complicated gear? Try building a full-wave loop antenna.

This design uses a loop with a perimeter equal to one wavelength, giving you better efficiency and a more balanced radiation pattern compared to basic antennas.

Why hams love it:
• Lower noise pickup (great for cleaner signals)
• Around 2 dB gain over a dipole
• Works across VHF, UHF, and even FM bands with simple scaling

It’s compact, easy to build, and surprisingly effective for both transmitting and receiving.

If you enjoy DIY radio projects, this guide walks you through dimensions and construction step by step:

🔗 https://vu3dxr.in/full-wave-loop-antenna-for-vhf-uhf-fm-radio-bands/

VHF DXing Secrets: The Ultimate Guide to Tropospheric Ducting for Radio Hams

Ever heard signals travel hundreds or even thousands of kilometers beyond line-of-sight? That’s not magic—it’s tropospheric ducting.

This fascinating radio phenomenon happens when atmospheric conditions (like temperature inversions and high-pressure systems) bend and trap VHF/UHF signals, letting them travel far beyond their normal range.

For ham radio operators, this means unexpected DX contacts, strong distant signals, and sometimes even interference from stations you’d never normally hear.

If you’re into radio, propagation, or just curious how the atmosphere can act like a giant waveguide, this guide is worth your time:

🔗 https://vu3dxr.in/ultimate-guide-to-tropospheric-ducting-for-radio-hams/

Microphone Preamplifier with Audio Peak Limiter

Microphone Preamplifier with Audio Peak Limiter: Build a simple microphone preamplifier with audio limiter using 2N3904 transistors and 1N34 diodes. Ideal for ham radio, DIY audio, or voice processing

Build a RF Dummy Load

 

A RF dummy load is quite useful when working on transmitters. It allows you to test and adjust the transmitter without an antenna, eliminating interference to other radios on your test frequency. It also presents your transmitter with a proper 50 Ω load so as to not cause any damage to its final RF amplifier stage.

A recent project required me to modify and align twelve UHF transmitters. The transmitters had a 25 watt output and the alignment session on each would be short. Rather than buy a dummy load for this project, I decided to build my own.

The central part of the dummy load is a resistor (or resistors) with a total resistance of 50 Ω and a wattage equal to or greater than your transmitter. The resistors also must be non-inductive which eliminates all the common wire-wound power resistors. Acceptable types of resistors include carbon composition and thick film.

For the resistor in this dummy load I chose a #32-1007 50 Ω flanged termination unit from Florida RF Labs with a rating of 40 watts. Other parts include an aluminum case, heatsink and SO-239 connector.

Construction is rather simple. First the heatsink and SO-239 connector are bolted to the case. Be sure to use heatsink compound between the heatsink and case.

Next holes are drilled and tapped for the flanged termination unit. The flanged termination unit also gets a thin coat of heatsink compound before installation. Its lead is extended with a short piece of wire to reach the SO-239 connector.

A quick check with a SWR Meter shows a VSWR of 1.1, an excellent reading.