xtgabyDec 30, 20201 minMeasurments 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. In...
xtgabyDec 26, 20201 minMeasurments 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 tur...
xtgabyDec 1, 20202 minAnalysis 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...
xtgabyNov 29, 20201 minBandpassfilter 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. ...
xtgabyNov 22, 20201 minBandpassfilter 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 (pri...
xtgabyNov 19, 20201 minBandpassfilter 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 in...
xtgabyNov 14, 20201 minBuilding 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...
xtgabyNov 1, 20201 minBuilding 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 Primar...
xtgabyOct 26, 20201 minInsertion loss measurements.FT240-31 ===> FT240-31 FT240-31 ===> FT240-43 FT240-31 ===> FT240-61 FT240-31 ===> FT240-77 FT240-31 ===> FT240-31 FT240-31 ===> ...
xtgabyOct 24, 20201 minBalun/Unun 1/9 ==> 50/450 Ohms.FT240-31, FT240-43, FT240-61 and FT240-77 Remark: 31 material is designed for 1-10 MHz common mode suppression and not recommended for im...
xtgabyOct 21, 20201 minRevised 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 ...
xtgabyOct 18, 20201 minInsertion loss measurement with FT240-31 and FT240-43I placed an adjustable capacitor between the two cores, and adjusted de capacitor for minimum SWR.
xtgabyOct 15, 20201 minFT240-31 versus FT240-43Remark: 31 material is designed for 1-10 MHz common mode suppression,and not recommended for impedance transformers (baluns/ununs). 43 ma...
xtgabyOct 14, 20201 minA 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 behav...
xtgabyOct 13, 20201 minBalun 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 coi...
xtgabySep 28, 20201 min50 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 squa...
xtgabySep 24, 20201 min50 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 ...
xtgabySep 3, 20201 minCase 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...
xtgabyJul 29, 20201 minTransformers 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 /...
xtgabyJun 1, 20202 minBuilding and measuring ununsRemark: all return loss measurements (SWR) are with a light inductive load (adjustable resistor). Real results are always better then sta...
