144 MHz Preamp using ATF54143
Preamp using the ATF54142 FET This design was made in 2006. It came back to my attention as my friend Jack PE1KXH asked for another […]
100 – 1000 MHz
AD8307 Frequency compensated
The AD8307 is a nice logarithmic amplifier with a lot of uses for amateur radio. My SWR Power meter is build around it. (LINK) The […]
ON4CDU, GPS frequency standard & much more
On his webpage Hans published his GPS receiver already a long time ago. It can be found HERE As an extra Hans put in the […]
Broadband amplifier from 50 to 450 MHz
For my newly build 50-70 MHz amplifier I needed a suitable driver. I needed about 5W drive. I started with a CATV module, the BGY888. […]
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 […]
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 […]
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 […]
Wilkinson divider for 145 MHz
For operation on 2320MHz I needed a receive power splitter for my IF 144 MHz. It had to cover the 100-150 MHz range. The first […]
Using the specan as a dipmeter
Using the spectrum analyser as a dipmeter For a long time I never had the need to have a dipmeter for HF and VHF. This […]
PCB low pass filters
In a discussion I had with Peter, SM2CEW and Graham, F5VHX, the idea grew to make simple low pass filters. Simple but suitable for fairly […]