- This topic has 1 reply, 2 voices, and was last updated 1 month ago by LectronFan.
May 2, 2020 at 15:40 #8601Guenni75Moderator
A couple of years ago a simple SW radio (“Retro Radio”) was offered as a kit made in China with a laminated cardbox housing in a nostalgic design remembering the 1950ies year radios… The common schematic was like the following one:
Let’s have a look at the left part until the red line: a very simple receiver with a feedback (P1) to increase the amplification. The voltage is limited by the LED, the antenna coupling shows different possibilities depending of location, SW band, radio station power, antenna length and the like.
I decided to spend some of my Lectron tuning blocks to build my own versions. Following several solutions with earphone, loudspeaker, different amplifiers and 2 special blocks (crossing with 330 µF, BC107 amplifier) ordered by INELCO in the 1970ies for their Sistema 2000 as parts of the extension set 2005.
The tuning has to be done with two hands: first the station, parallel the feedback control with a maximum of volume and a minimum of feedback noise (howl). As an alternative an additional coil for AM BC may be used and allows via a simple switch the choice of SW or BC:
Here with a frequency meter unit – a low cost article from China… :
Here a QM version:
This is a typical legacy block version:
This is a version for (-) on GROUND:
… and this was one of my proposals for the 50th anniversary of Lectron 2016 as a Special Edition… :
There are many SW stations “switched off” or changed to DRM mode – but a lot of other stations can still be found from 18:00 (wintertime) or 20:00 (summertime) in the range of 4 MHz … 15 MHz. Often only for 10…30 minutes for actual news, sometimes longer with national music, stories or languages courses (Chinese!).
- This topic was modified 1 month ago by Guenni75.
May 3, 2020 at 08:06 #8619LectronFanModerator
Thank you Günther for these fantastic circuits. I’d wish I has some empty blocks to build them all !
It’s amazing so many different design of receivers you come up with !
I need to focus on 1 or max. 2 receivers and “steal” the housings of existing modules.
I’d wish Lectron opens soon (closed due to the corona virus), so I can order some.
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