- Like many fellow radio amateurs, I own a fairly standard shortwave radio station consisting of a 100W HF transceiver driving a 1kW tube power amplifier. I never chose to spend any money on a kW-rated antenna-tuner. Anyhow, I can tune out VSWRs as high as 3÷1 with the adjustable pi-network of the output filter tank inside my power amplifier.
Thus I set out to design an HF antenna with a VSWR of 3÷1, or less, over the full bandwidth of as many amateur radio HF bands as possible. At the same time, my preference went out to the low- and the non-WARC bands. This design exercise resulted in a new kind of antenna which I dubbed Center-Loaded Off-Center-Fed Dipole Antenna, or CL-OCFD for short.
- In proof of its performance, an EZNEC-calculated VSWR-graph of the CL-OCFD antenna is presented in Figure 2. This antenna works without a tuner over the entire bandwidth of the 80, 40, 30, 20, 15 and 10m-band, simply by adjusting the output-tank of your tube power amplifier. —If your final output stage is a transistor amplifier, you definitely will need an antenna-tuner though.— In such, this antenna is the first described single-wire antenna to be offering these capabilities.
See Full Article: Link
The International Amateur Radio Union (IARU) Administrative Council has recognized Hans Zimmermann, HB9AQS/F5VKP, for his success over many years in r... Read more
The 40 MHz OZ7IGY beacon was migrated to the Next Generation Beacons platform on March 25. The beacon was activated during a 60th anniversary event fo... Read more
DX vertical antenna for low-bands 80/160 NEW Height 22 meters 5kw power Elements diameter from 75 to 25 mm Hardware full stainless steel Coil of alumi... Read more
Antennas and more questions from the Technician exam pool. Read more
This app answers the two basic questions facing radio amateurs:- Which band shall I use ? Where shall I point my beam ? It will be of interest to an... Read more
In this video we run through setting up a bluetooth CAT control for the Yaesu FT-817, using an Android Tablet, bluetooth interface, and Yaesus... Read more
Airspy HF+ and SpyServer streaming FFT and Audio data to an Android watch. @mm6dos Took the concept a step further! #sdrsharpinside pic.twitter.com/bW... Read more
An Oggie asks why his radio draws so much more power than the 100 watts it puts out. The answer lies in using linear final power amps in the Class A,... Read more
The Wireless Institute of Australia (WIA) reports Australia’s communications regulator ACMA is reinstating the reciprocal arrangement for US Amateur R... Read more
Explaining Ham Radio Antenna Baluns, UNUNs and Toroids Read more