Chinese attenuators (ebay)
I needed some SMA attenuators for my SWR-Wattmeter project. I found the available for abt $7 (2016) on Ebay. These are available in 6, 10, […]
RF construction
Coaxrelay homemade out of cheap relays
The need for coaxrelays for the new 50-70 MHz amplifier led to this design. I had very good experiences with the Fujitsu relay which datasheet […]
Coupler from 1.5 to 70 or 80 MHz
Coupler from 1.5 to 70 or 80 MHz Published here are 2 couplers with a T94-2 and a T94-6. The first coupler was build with […]
PA protection system
In order to provide a more clear overview on the protection system. You will find the blockdiagram below: It consists of the Power / SWR […]
Universal triode input board
To build another tube amplifier, I needed a matching to the 50 Ohm output of my solid state transceiver. It had to be universal and […]
144 MHz Bandpass filter revisited
144 MHz Bandpass filter revisited The 144 bandpass filter as shown on my website (here) has been a very popular article. It was the most […]
Receive splitters HF
To experiment with 2 receive antennas on the lower bands I needed some kind of splitter / combiner with some isolation between te ports. A […]
600M Power coupler
Below some photographs of my 300 KHz to 5 MHz coupler. The coupler is build on a Philips core. Probably the TN 36/23/15 3C90 material. […]
HF-high power coupler 1,5 – 30 MHz
For my Arduino power / SWR meter needed a coupler for 1.5 – 30 MHz. It was easy to find a design. I used the […]
Gysel couplers
The Gysel coupler (under construction) There are many ways in combining amplifiers. Wilkinson dividers, hybrid couplers or rat-race couplers are the best known couplers […]