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When my father - who became a ham years after I did - passed away, I found an unstarted project (board + components), which I only re-discovered again years later.

The board is marked DK0TV-001, and uses three ICs (as marked on the silk layer) SO42P, TCA1047 and TAA611. Apparently it converts 30 MHz to 10.7 MHz using the SO42P (with a 40.7 MHz crystal), then demodulates and amplifies.

Looking over the internet DK0TV barely pops up, a little strange considering this seems to have been the club callsign of a german broadcast station (ZDF2?).

Even though this call/kit probably pre-dates the internet, I am somewhat saddened I could find so little, and somewhat intrigued what this kit was about. Anyone remembers this?

Added images

PC board Components

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    $\begingroup$ Interesting, can you add a photo or two to your question? $\endgroup$
    – Mike Waters ♦
    Jan 4, 2020 at 18:43
  • $\begingroup$ Sounds like a transverter? Although most modern HF radios would be able to do both 10mhz and 30mhz without a transverter. $\endgroup$
    – user10489
    Jan 5, 2020 at 1:15
  • $\begingroup$ We can tell you a bit about the ICs as far as we can recognize them, but the whole thing will be more interesting if we have an overview of the device – ideally, a schematic, but assuming that'll be hard to come by ad-hoc, a picture of the board (from both sides!) would be good a start. $\endgroup$
    – Marcus Müller
    Jan 5, 2020 at 14:41
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    $\begingroup$ @MikeWaters, I've added a couple of images. Sorry for the delay - I didn't have access to the kit. $\endgroup$
    – jcoppens
    Jan 7, 2020 at 14:32
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    $\begingroup$ Why would a transverter from that era convert to 10.7MHz? That's a common IF frequency for receive but no one would have had a rig capable of transmitting on that frequency. I'd say it's a down converter of some sort, perhaps for satellites (the early OSCARs had downlinks on 29MHz) or maybe it's a UHF down converter (for fast scan TV)? $\endgroup$
    – Duston
    Jan 7, 2020 at 15:14

1 Answer 1

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This kit is a FM receiver built in 1977 by DK0TV. The receiver works on a single fixed frequency 30.000 MHz FM and has a very good sensitivity. It is used with a 10 GHz Gunnplexer to listen to the 3 cm band with a 30 MHz intermediate frequency.

Here are details on how it works:

  • The input at 30 MHz is amplified by a dual gate MOSFET
  • The S042P is a mixer with a local crystal oscillator at 40.7 MHz delivering an intermediate frequency at 10.7 MHz (40.7 - 30 = 10.7)
  • The TDA 1047 is the FM demodulator working at 10.7 MHz and giving the demodulated audio at its output (not a TCA 1047)
  • The TAA611 is the audio amplifier

This receiver can be used for example with a 10 GHz cavity with a Gunn diode to generate a local oscillation which is 30 MHz up or down from the frequency you want to receive on the 3 cm band. The 10 GHz elements are not in the kit.

enter image description here

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  • $\begingroup$ Thanks Bernard - very helpful! Any idea where to obtain the schematic? Maybe this project was published in a magazine? $\endgroup$
    – jcoppens
    Nov 12, 2021 at 18:45
  • $\begingroup$ By the way, I just found a very short reference to the project in this magazine: aef.se/Amatortidningar/QTC/QTC_1979-1983/qtc_1981_3.pdf, page 89. At the time, I had done some experiments on 10 GHz, so maybe he wanted to get in the game... $\endgroup$
    – jcoppens
    Nov 12, 2021 at 18:59
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    $\begingroup$ Hello Bernard, and welcome to ham.stackexchange.com! Nice first answer! $\endgroup$
    – rclocher3
    Nov 13, 2021 at 17:08
  • $\begingroup$ Here is a schematic i have, it is a png file with low definition, i found it years ago on the internet but it can help ! Thanks for the link with the pdf document. $\endgroup$
    – BERNARD
    Nov 13, 2021 at 18:06

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