DK7IH Information

Welcome to my private blog on software and hardware development and radio engineering science. The circuits presented here are free to be used within the amateur community. Commercial exploitation requires permit for usage and modification. I don’t sell radios nor do I have any circuit boards or ready made modules for sale. This website is a non-commercial scientific publishing.

If you have any questions, comments or ideas, you may wish to mail me: dk7ih[at-character]yahoo.com

Site owner: Peter Baier, Lichtenfelser Str. 35, 76887 Bad Bergzabern, Germany

Book: Amazon (3rd Edition, sold out), Online version (German only)


Profession: I graduated from college in science (Physics and IT), earned a teaching degree in secondary education and have been working as a science teacher up to today. After having graduated from college I worked as a software and hardware developer for a number of years. Mainly I have been occupied with projects in the field of technique of measurement, sensor interfacing, database development. Also I have been occupied with macro programming for Microsoft products and learning software.

My main language nowadays is the “C” programming language, but  there also were lots of projects in Visual Basic and PASCAL the recent decades. Today all my computer work is in the embedded systems sector (ATMEL AVR microcontrollers) for my private  radio and scuba diving material.

Amateur radio acitvities: Before gaining my radio amateur license in 1987 I have long been a home constructor of radio equipment. Must have been a virus I aquainted from my father who built vacuum tube equipped radios, remote controls for ship models and other radio and electronics related stuff.

By the age of 8 or 9 I started to build simple receivers for medium and short wave. I listened to all the stations from all over the world. Later by accident I found some CBers in my 27 MHz diode receiver and since then I have been hooked to radio frequency communications.

First I started with a simple 2 transistor AM transmitter built on the board of my Philips Electronic experimental kit. For the receiver I used a regenerative technology made genuinely for rc models. My first real contact via a home built radio was down the street where an elderly CBer who called himself “Alpha 1” had his station. Distance must have been 500 meters or so but I was happy he could read me and we could talk via the radio. 😉 The radio was built on a piece of cardboard and from today’s point of view it was some sort of horror trip concerning the design. Proper grounding? Oh, forget it! 😉

Later I built crystal controlled AM CB radios on Veroboards that had more power and was “on air” regularly with them. Always looking out of the window of our flat if there was radio detection car of the Federal Communication Office ’round the corner’. Guess what I did was not 100% legal, or to say more exactly, it was illegal. But who cares nowadays? 😉

When I was about 12 or 13 years old I got interested in “real” ham radio. I pulled tubes out of old radios and started to build short wave transmitters. EF80 was my favourite tube for oscillators, EL84 for the final. A nice circuit that time was a small QRP transmitter for AM equipped with 2 pentodes from the late 70s:

It worked pretty well. A friend of mine was able to receive my signals on 80 meters with a modified kitchen radio over a distance of about 10 kilometers. That was fun! 😉 What my parents did not think to be funny were unexpected “visits” of the local police investigating in the case of illegal transmitting activities and confiscations of several technical things from our household like my mother’s kitchen radio. 😉

Later I re-participated for some years in CB radio again with homemade AM rigs. I used and refined 27-MHz-remote control circuits that I modified for voice communication. I went away from working with tubes because rf-capable transistors were commonly available for reasonable prices. The schematics for the 27-MHz-RC-circuits had been widely published in literature that time (German authors e. g. Heinz Richter or Gerhard O. W. Fischer) because people were allowed to build their own remote controls for ships and aeroplanes under some limited conditions. My father did so, thus all the neccessary equipment was available in our home. He even owned an oscilloscope, an older Heathkit one.

Then I finally decided that CB might not be the right field for experimenting and constructing my own radio communications equipment. I made up my mind to learn morse code (which was mandatory in those times to achieve a short wave ham licence) by writing a software to practise with on an old ATARI 600 home computer and afterwards applied and passed the licence exam. I got my license with the first attempt.

Nowadays I don’t use any commercial equipment except from test equipment. All my HF rigs are homemade. So my main interest in amateur radio is homebrewing SSB transceivers (gave up morse code decades ago, have to admit 😉 ), working with and programming microcontrollers, electronics of all kind. I really love to to construct gear that performs well and looks good. “Ugly construction” is not among my preferred techniques. 😉

In amateur radio I’m fascinated of making world wide communication with very little effort. The internet just can’t compete with that! 😉

Besides technical hobbies I also love sports, e. g. scuba diving, cycling, hiking and, in general, outdoor activities.

Peter (DK7IH)

One Reply to “DK7IH Information”

  1. Hello Peter.

    Feeling unable to communicate well, this is written with google translator.
    If you do not understand, you spoke to my girlfriend, she will know German, Russian, Polish, Spanish, and a little English (I do not know what to see in me, I do not speak languages. :-p)

    I also like the amateur radio, indicative EA5IQF. … and … scuba diving 🙂 up to 38m,.

    I would be delighted, with your projects, the radio.

    “Give me FIVE!” – QRB SSB multiband transceiver for 5 bands with 10
    Watts output power

    Very very very good !!
    Schemes, very well done, separated into “groups” to see well and understand.
    Now I, I only have a transmitter of 27 mhz, I like a lot, I also walk 2m.

    I would like to make your project, project free, strong, not have “scheduled obsolescence” … and be personal.

    I do not care. To make circuits, to weld transistors, resistors, and coils, relay, … my knowledge to be of electronic hobby, law of ohm, kirchhoff,
    Level I of electronic / electricity.
    My job is, maintenance in factory, electricity, sensors, transducers, frequency inverters, mechanics, etc.

    Like you, I also like radio lamps, I restore, and free time old radios, tubes, not be an expert, but … areglarlas 😉

    Questions :

    1) All the project, the materials. how much price to leave, approximate?

    I program In Mega … never do, if you can mount, but never program or dump data.

    I try to do, by myself, or seek help, from friends, programmers.

    2) In the worst case, if I assemble and mail you, I can send scheduled, I pay the shipping costs round trip and work hours.

    3)To be able to do more “rustic” version “for my level”, with VCO, and see frequencies with the Asian frequency meter?

    “Can be made”, a removable module, with connectors, for quick connection, and to remove on the one hand,
    And call it “experimentation module Quick ” or “test module”, just like you have with socket,

    I also like CB, but this already be, personal taste, I hope you like the idea of “removable module of rapid experimentation”

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