Used material: Amidon FT240-43 cores. LEFT = 2 conductors RIGHT = 4 conductors Left: transmission line with an impedance of 100 ohms....

For building descriptions, see my previous blogs. Return loss measurements: Insertion loss measurements: Insetion loss @ 14 MHz = 0.2 dB...

Insertion loss: Return loss: Common mode rejection:

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:...

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...

Input / output impedance = 600 Ohms Measuring setup: Transformer impedance ratio = 600 / 50 = 12 I have ended with 3 turns / 10 turns....

Input / Output impedance = 2.000 Ohms Measuring setup: Transformer impedance ratio = 2.000 / 50 Ohms = 40 I started with 2 turns / 13...

How does it work? Depending on the selected frequency, one of the six available filters is activated. This is done by controlling a relay...

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....

Important: only for receivers. This filter can not handle transmitted power. Picture: The Kank 3334 transformer from Toko has on one...

Important: only for receivers. This filter can not handle transmitted power. Band pass filters are used to effectively suppress strong...

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...

Schematic: Buiding the transformer: 1) drilling the holes 2) Placing the hardware 3) Schematic 4) Winding the transformer...

FT240-31 ===> FT240-31 FT240-31 ===> FT240-43 FT240-31 ===> FT240-61 FT240-31 ===> FT240-77 FT240-31 ===> FT240-31 FT240-31 ===>...

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...

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...

I placed an adjustable capacitor between the two cores, and adjusted de capacitor for minimum SWR.

FT240-43 FT240-31 FT240-31 FT240-43 FT240-31 FT240-43 FT240-31 FT240-43

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...

Use this balun allways in combination with an 1:1 current balun! Schematic diagram: Used material: FT 240-43 Amidon Primary (left): 2...