top of page
Search


Comparative measurement between 61, 67 and 73 material.
I made a 1:1 transformer with 3 turns primary and 3 turns secondary. The coil value of 3 windings of the 61 material...
xtgaby
Apr 141 min read
Â
Â
Â


Combining FT240 and FT140 cores And theire AL values
Did you know that an FT140 core fits exactly in an FT240 core? FT240 - 31 with 2 x5 turns (upper picture left) FT240 - 43 with 2 x5 turns...
xtgaby
Feb 41 min read
Â
Â
Â


1:49 balun with FT400-43 material and the influence of the winding method on the measurement results.
6 windings together and 8 windings distributed over the core Windings distributed over the core Schematic: First measurement:...
xtgaby
Oct 28, 20241 min read
Â
Â
Â


Wall-mounted loop antenna
To reduce interference from man-made noise, I often use a loop antenna which is known for its ability to decrease unwanted signals. I...
xtgaby
Aug 18, 20241 min read
Â
Â
Â


Vertical antenna with 2 elevated radials for the 20 meter band.
A pole of 10 meters is used. From the top to the middle (feedpoint) 5 meters of 2.5 mm² is used. From the middle (feedpoint) two radials...
xtgaby
Jul 18, 20241 min read
Â
Â
Â


How the ATU was build
Bottom view: Top view: Schematic diagram Air coils: Wire diameter = 0.8 mm Diameter pen = 9.7 mm L1 = 2 turns L2 = 3 turns L3 = 5...
xtgaby
Jun 29, 20241 min read
Â
Â
Â


Measurements to determine practical losses in an ATU (Antenna Tuning Unit).
I built two identical tuners to go from 50 Ohms to a complex impedance and then back to 50 Ohms. This makes it easy to measure the...
xtgaby
Jun 15, 20242 min read
Â
Â
Â


Guanella 1/4 balun 1 core versus 2 separated cores.
It was my friend Eric ONBEW who drew my attention to a number of articles (from G3TXQ, DJ0IP and W7EL), which mentioned that a 1/4...
xtgaby
Dec 5, 20232 min read
Â
Â
Â


Receiving loop antenna for indoor or portable use revised version.
New version Old version I changed the shape from square to circle. Height and width of the loop are 1 meter. This means that one...
xtgaby
Aug 26, 20231 min read
Â
Â
Â


Guanella 2/1 current balun
Picture: Upper core = FT240-43 1:1 curent balun Lower core = FT240-43 1:4 Guanella current balun Wires are wound in a different way! Take...
xtgaby
Jan 5, 20231 min read
Â
Â
Â


The use of a line output transformer core to make a balun.
Be careful when removing the core as it is very fragile! 10 windings were made both top and bottom. They behave like 100 ohm transmission...
xtgaby
Apr 21, 20221 min read
Â
Â
Â


Receiving loop antenna with 3 turns i.s.o. 2 turns.
Height and width of the loop are 1 meter. This means that one turn = 2.80 meters. In this case i have used tree turns = 8.40 meters. New...
xtgaby
Jan 13, 20221 min read
Â
Â
Â


Receiving loop antenna for indoor or portable use.
Height and width of the loop are 1 meter. This means that one turn = 2.80 meters. In this case i have used two turns = 5.60 meters. I...
xtgaby
Jan 10, 20221 min read
Â
Â
Â


Loop On Ground Antenna
The feedpoint Square with a side = 5 meters Hard to see on the picture. top left is the feedpoint Used material: 1 core of 73 material...
xtgaby
Aug 17, 20211 min read
Â
Â
Â


Guanella 1/6 current balun.
Pictures: Schematic: U out = 2.5 x U in ==> Impedance Out = 2.5 x 2.5 = 6.25 x impedance In @ 50 Ohms in, Out = 312 Ohms. Measuring...
xtgaby
May 2, 20211 min read
Â
Â
Â


Guanella 1/9 current balun.
Picture: Schematic: Input: 3 transmission lines with an impedance of 150 ohms in parallel = 50 Ohms, Output: 3 transmission lines with an...
xtgaby
Apr 24, 20211 min read
Â
Â
Â


Building a QRO 1/49 transformer for end fed antenna.
Used material: - 3 cores Amidon 240-43 - copper wire 1.8 mm diameter - PTFE tube with 2 mm internal diameter and 3 mm outside diameter -...
xtgaby
Mar 28, 20211 min read
Â
Â
Â


The Turrin balun
Used material: FT240-43 Schematic: Insertion loss: Return loss: Common mode rejection:
xtgaby
Mar 13, 20211 min read
Â
Â
Â


Guanella 2 wire balun versus Ruthroff 3 wire balun.
Guanella 2 wire Ruthroff 3 wire Schematic: Guanella 2 wire Ruthroff 3 wire Return loss: Guanella 2 wire Ruthroff 3 wire...
xtgaby
Mar 7, 20211 min read
Â
Â
Â


The Ruthroff balun (1/1 3 wire version).
Used material: AmidonFT240-43 core. Top view Bottom view This is the way I think it should be made. Schematic: Insertion...
xtgaby
Mar 7, 20211 min read
Â
Â
Â
bottom of page