Updated 29.03.2015: HF Ferrite Tube Baluns
Here is a short story of magnetic baluns, which we winded using parallel ferrite tubes. These baluns are typically used as impedance transformers with symmetrical, high-impedance HF transmitting antennas, like terminated V-beams, Rhombic's and T2FD's. Test results of 1:9, 1:12 and 1:16 baluns.
Download the PDF file: tube baluns.pdf
29.10.2013: HF Coaxial-Toroid Choke
This is a simple toroid-based coaxial mantel current choke (current balun) to use with low-power transmitters. Device works on 1 to 30 MHz and is able to handle over 100W carrier power.
Download the PDF file: CMC.pdf
07.10.2013: HF Balun 1:4
This is a wide band antenna transformer used with various balanced antennas. It is a traditional Guanella-type current balun. This medium power balun can handle over 100W transmitter power.
Download the PDF file: balun 1 to 4 dual.pdf
Updated 30.03.2015: HF Unun 1:9
These are wide band unbalanced antenna transformers, used with various long-wire antennas, Beveridges and with some vertical antennas. Low power toroid and medium power ferrite tube constructions.
Download the PDF file: unun 1 to 9.pdf
Updated 23.10.2019: T2FD-NVIS Antenna
Wideband T2FD type suits well for amateur radio stations general purpose antenna. It has low SWR; usually it works without antenna tuner. T2FD is fine listening antenna; it is rather immune to wide-band urban noise. This version is omni-directional NVIS version assembled as inverted-V dipole.
Download the PDF file: T2FD_NVIS.pdf
03.07.2017: Terminated Wire, HF antenna
This antenna is fast to build: single wire, feeding/termination points at ground level. Traveling wave noise-free antenna, which presents wide frequency range without tuner. Not the best selection for fixed location QRP or DX working. Optional use as open Long Wire with antenna tuner.
Download the PDF file: Terminated Wire.pdf
OH1AYR is an amateur radio station.
Locator: KP11LC, N 61.0838, E 22.9175.
Operator , license since 1982.
Lazy phone operator: sometimes heard on 3.7 MHz SSB. Favorites: Wire antenna testing, QRP & digi. Member of SRAL & OH1AL. QSL via eQSL. More info on QRZ.com. Sorry, we do not sell antennas or components.