Montag, 29. September 2025

coffee can antenna - 2m tuned lamda/2

This fantastic antenna was featured in the May 1983 issue of "73 Magazine," pages 54-55. 

Assembly was straightforward and problem-free.
 
 
   
 
 

 

Freitag, 26. September 2025

"Pressespiegel" - Box

 

RAI Südtirol always broadcasts the reviev of the newspapers at a time
when I'm on my bike cycling to the office. 
Since this "voice recording module" has recently become available that can record
17 minutes, I built this box, together with an Arduino UNO, a HW-84 real-time clock, and a TEA5767 FM radio module, 
which always plays the latest "press review" at the touch of a button.
 
 

 
 

 

Donnerstag, 11. September 2025

Measuring the "FM band stop filter"

 

I quickly tested the MRDDZ BS "band-stop filter." The results weren't satisfactory:
 
                                        Measuring only the throughpass
  Marker 2: 150 MHz 
                   no 2m amateur radio - no AIR-band - no 136 WX satellites ...
88,5 MHz: -11,4 dB / 108 MHz: -21,4 dB


 

Montag, 10. Februar 2025

Broadband loop antenna

The efficiency of this broadband loop antenna is naturally low. The advantage is the broadband nature of the antenna. 

The diameter is 1.2 metres. 

In 40mB the efficiency is too low when transmitting, 30mB and 20mB are okay. From 17mB upwards the diameter is too large. The reception is not so strong but relatively quiet.