xtgaby
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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, 2020
- 1 min
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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xtgaby
- Sep 17, 2020
- 1 min
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 ...
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xtgaby
- Sep 3, 2020
- 1 min
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...
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xtgaby
- Jul 29, 2020
- 1 min
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 / ...
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xtgaby
- Jun 1, 2020
- 2 min
Building and measuring ununs
Remark: all return loss measurements (SWR) are with a light inductive load (adjustable resistor). Real results are always better then...
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xtgaby
- May 31, 2020
- 1 min
Magnetic loop 160 meter.
Calculated coil value of the loop is 6.4 uH as explained in de 40 meter band loop. Target frequency = 1.858 KHz Calculated capacity...
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xtgaby
- May 30, 2020
- 1 min
Magnetic loop 80 meter band.
Calculated coil value of the loop is 6.4 uH as explained in de 40 meter band loop. Target frequency = 3.700 KHz Calculated value for the...
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