xtgaby
1/1 Current Balun with 15 turns on Wurth core 74270191 for better low frequency behavior.
Insertion loss: Return loss: Common mode rejection:
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xtgaby
Jan 30, 20211 min read
1/1 Current Balun with 10 turns on Wurth core 74270191
On both sides, i placed 10 turns teflon wire. Insertion loss: Worst case = 0.09 dB @ 30 MHz. This means a power loss of 2 %. Return loss:...
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xtgaby
Jan 16, 20211 min read
Measurements on output transformer final amplifier TS440.
The TS440 power amplifier is a push-pull amplifier with a very low output impedance. To make a conversion to 50 ohms, a 1/16 impedance...
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xtgaby
Dec 30, 20201 min read
Measurments on Kenwood YK-88CN CW Narrow filter.
Input / output impedance = 600 Ohms Measuring setup: Transformer impedance ratio = 600 / 50 = 12 I have ended with 3 turns / 10 turns....
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xtgaby
Dec 26, 20201 min read
Measurments on muRata CFJ455K 14
Input / Output impedance = 2.000 Ohms Measuring setup: Transformer impedance ratio = 2.000 / 50 Ohms = 40 I started with 2 turns / 13...
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xtgaby
Dec 1, 20202 min read
Analysis of a Kenwood TS 440 filter unit.
How does it work? Depending on the selected frequency, one of the six available filters is activated. This is done by controlling a relay...
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xtgaby
Nov 29, 20201 min read
Bandpassfilter for 80 meter band (3.5 MHz) with Amidon T50-2 cores.
5,5 µH coil versus 55 µH coil. Picture: Schematic: 34 turns = 5.5 µH capacitor is approx. 320 pF. 104 turns = 55 µH capacitor is approx....
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xtgaby
Nov 22, 20201 min read
Bandpassfilter for 40 meter band (7MHz) with Amidon T50-2 cores.
Important: only for receivers. This filter can not handle transmitted power. Picture: The Kank 3334 transformer from Toko has on one...
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xtgaby
Nov 19, 20201 min read
Bandpassfilter for 40 meter band (7MHz) with Toko Kank 3334 transformers.
Important: only for receivers. This filter can not handle transmitted power. Band pass filters are used to effectively suppress strong...
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xtgaby
Nov 14, 20201 min read
Building an endfed antenne "the sequel".
Schematic: For the 40, 20, 15 and 10 meter band, I have shortened the first part of the antenne from 20.40 meters to 20.15 meters. I have...
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xtgaby
Nov 1, 20201 min read
Building an endfed antenne kit (from www.hfkits.nl) with 1:49 transformer.
Schematic: Buiding the transformer: 1) drilling the holes 2) Placing the hardware 3) Schematic 4) Winding the transformer...
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xtgaby
Oct 26, 20201 min read
Insertion loss measurements.
FT240-31 ===> FT240-31 FT240-31 ===> FT240-43 FT240-31 ===> FT240-61 FT240-31 ===> FT240-77 FT240-31 ===> FT240-31 FT240-31 ===>...
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xtgaby
Oct 24, 20201 min read
Balun/Unun 1/9 ==> 50/450 Ohms.
FT240-31, FT240-43, FT240-61 and FT240-77 Used material: FT240-31 Start version Tuned version for best SWR (move the coils for best...
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xtgaby
Oct 21, 20201 min read
Revised edition. Building and measuring baluns (Part I)
Go to Building and measuring baluns (Part I) and see the results of the guanella 1:4 balun now with teflon insulated wire. FT240-31 with...
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xtgaby
Oct 18, 20201 min read
Insertion loss measurement with FT240-31 and FT240-43
I placed an adjustable capacitor between the two cores, and adjusted de capacitor for minimum SWR.
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xtgaby
Oct 15, 20201 min read
FT240-31 versus FT240-43
FT240-43 FT240-31 FT240-31 FT240-43 FT240-31 FT240-43 FT240-31 FT240-43
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xtgaby
Oct 14, 20201 min read
A practical way to determine the value of the compensation capacity.
I have used an adjustable capacitor with a value between about 5 and 60 pF. Now you can change the capacity until you have the best...
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xtgaby
Oct 13, 20201 min read
Balun for Delta loop and quad.
Use this balun allways in combination with an 1:1 current balun! Schematic diagram: Used material: FT 240-43 Amidon Primary (left): 2...
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xtgaby
Sep 28, 20201 min read
50 to 100 ohm transformer for receiving systems.
5 turns input 7 turns output Used material: 1 core of 73 material Fair-Rite 2873000202 Input = 5 turns / Output = 7 turns 5...
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xtgaby
Sep 24, 20201 min read
50 to 75 ohm transformer for receiving systems.
4 turns input 5 turns output Used material: 1 core of 73 material Fair-Rite 2873000202 Input = 4 turns / Output = 5 turns 4 square...
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