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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....
xtgaby
Dec 30, 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...
xtgaby
Dec 26, 20201 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...
xtgaby
Dec 1, 20202 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....
xtgaby
Nov 29, 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...
xtgaby
Nov 22, 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...
xtgaby
Nov 19, 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...
xtgaby
Nov 14, 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...
xtgaby
Nov 1, 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 ===>...
xtgaby
Oct 26, 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...
xtgaby
Oct 24, 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...
xtgaby
Oct 21, 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.
xtgaby
Oct 18, 20201 min read
FT240-31 versus FT240-43
FT240-43 FT240-31 FT240-31 FT240-43 FT240-31 FT240-43 FT240-31 FT240-43
xtgaby
Oct 15, 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...
xtgaby
Oct 14, 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...
xtgaby
Oct 13, 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...
xtgaby
Sep 28, 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...
xtgaby
Sep 24, 20201 min read
9:1 transformer for K9AY antenna.
Picture Schematics primary 2 turns secondary 6 turns Used material: 3 cores of 73 material Fair-Rite 2873000202 Input = 2 turns ...
xtgaby
Sep 17, 20201 min read
Case study, how many turns are needed?
Picture Schematics Number of turns left = number of turns right. L value: XL value @ 1 MHz 1 turn: 0,02 mH 125 Ohms...
xtgaby
Sep 3, 20201 min read
Transformers for receiving antennas.
Used material: 73 material Fair-Rite 2873000202 How to build and measure. 1) One core 2 turns left and 3 turns right. Input = 2 turns / ...
xtgaby
Jul 29, 20201 min read
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