A few mods made by Jochen Heilemann DG2IAQ. Прислал Marek B. (SP2MKT).

A few mods made by Jochen Heilemann DG2IAQ

Microphone - change dynamic capsule to a electret capsule. Gives more gain and much better sound, especially on FM.

  • 10kOhm from +8V (PIN5)
  • 100nF to Mic out (PIN1)


  • C23 --> 1nF (TX, more heights)
  • C24 --> 1nF (TX, more heights)


  • C504 --> 330nF (TX, more basses)
  • C505 --> 330nF (TX, more basses)
  • C531 --> 4,7nF (TX, raise lowpass from 2,8kHz up to 3,2kHz)
  • C527 --> 3,9nF (RX, raise lowpass from 2,8kHz up to 4,0kHz)
  • C530 --> 560pF (RX, sharper lowpass curve at 4,0kHz)

TX-RX-Unit (RF):

  • C360 --> 1,8nF (RX, very more heights, lowpass 600Hz -> 3,2kHz)

With the last mod of C360 I got the high fidelity sound I would like to have. Now I also can use the NR.1 noise-reduction. At the original state the RX sound was to dark for me. I didn't unterstand the stations with switched on NR.1 ! My Clearspeech-DSP-speaker does a better job ! But now I have a much clearer RX sound and can use all features. With the build-in DSP you have now a great alignment space without raising the noise cause of my mods. Now try to hear a AM broadcast station. You also be able to hear (and understand) the music now without the dark sound.

Прислал Marek B. (SP2MKT)