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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 14, 20251 min read


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 4, 20251 min read


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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


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
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