Beginning home-brew projects

Discussion in 'Homebrew and Kit Projects' started by KM4LKC, Feb 15, 2017.

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  1. KM4LKC

    KM4LKC Premium Subscriber QRZ Page

    A small group of local amateur radio hobbyists would like to build a series of homebrew projects. Our initial goals are to build relatively simple components, learn to read the schematics, understand the theory of the circuitry, build the components and test the circuits as we progress.

    I would like to gather a progression of projects that will help us learn the basic concepts as we add components and complexity.

    Any input would be much appreciated.
     
  2. K7ELP

    K7ELP XML Subscriber QRZ Page

    I think I understand what you and the group wants to do. I think it is great. I don't believe you want to make the components( that is to say you don't want to
    make the resistors, capacitors, and semiconductors.) You can still make some inductors. What I am saying that there are 3 passive components and some active components. The active components are things such as transistors, integrated circuits and diodes or rectifiers. The only passive component to be hand made would probably be for frequencies about 1 megacycle or higher. You could make resistors, and capacitors, but the cost would be many times the premade cost of those items. I have a lot of experience in making all sorts of projects, I will be glad to help. My email address in the call sign data base.
    Good luck Ned
     
  3. KM4LKC

    KM4LKC Premium Subscriber QRZ Page

    Thank you Ned. You are correct...that was a poor choice of words on my part. Our thinking was to start with a receiver to understand the building blocks of the receiver - RF amp, pass filter, oscillator, mixer, etc. [I confusingly called these blocks components]. Next, we might build a transmitter. This could be followed by a keyer. And an antenna tuner. All of this completing a QRP rig in a modular format.

    Dave Richards, AA7EE version of the SST20 is a beautiful example but is likely a little advanced for our group. I hoped to get some ideas on projects that created a nice progression of ideas for learning the basics in amateur radio electronics.
     
  4. K9STH

    K9STH Ham Member QRZ Page

    I would start with a transmitter. A transmitter is considerably easier to get going than a receiver.

    Glen, K9STH
     
    W7UUU likes this.
  5. VK2TIL

    VK2TIL Ham Member QRZ Page

    Perhaps you could begin with a group purchase of Experimental Methods In RF Design (EMRFD); publication was discontinued but the ARRL has now begun to publish it again;

    http://w7zoi.net/em0_123.html

    The addition of SSD and IRFD to the ARRL "package" is a wonderful bonus; there is a great deal of knowledge in each.

    All that you propose is in there; it encourages the building & testing of modules which can then be connected together to make a complete receiver or transmitter.
     
  6. KM4LKC

    KM4LKC Premium Subscriber QRZ Page

    Thank you for the guidance. We'll start here.


    Perfect...this looks like the exact information we needed....Thank you!
     
    KI7ASV likes this.
  7. KI6J

    KI6J Ham Member QRZ Page

    Interface for PC sound card oscilloscope.
    Regulated power supply from a wall wart.
    Audio frequency amplifier.
    An XR2206 signal generator.
    An op-amp audio filter.
    Current limiting and crowbar circuit for the above power supply.
    LM567 tone detector.
    Diode RF probe.
     
    KA9UCN likes this.
  8. VK3YE

    VK3YE Ham Member QRZ Page

    I'd suggest some simple bits of RF test equipment (eg field strength meter, RF power meter), antenna accessories (eg ATU, SWR meter, QRP magnetic loop) and basic transmitters and receivers.

    A 2 or 3 transistor regenerative receiver can hear signals from around the world (but start with a coil for the AM broadcast band).



    FM can be heard on a superregen, though these can sometimes be fiddly.



    Very simple QRP transmitters can be fun, although crystal control can be limiting. This is a novelty hand-cranked tx.

     
  9. WB3BEL

    WB3BEL Ham Member QRZ Page

    I think that there are many good sources for simple projects.

    To add a few more:
    If the group is starting from really beginning level, and need to understand basic electronics, then the Hands on Radio series by Ward Silver N0AX that have been running for ages in QST have some good building blocks. If you are a member of ARRL you can read these online or download the ones of interest. A book has also been published with a collection of these, but I can't vouch for it and don't know much about it. It always seemed to me like a series like this which started with some circuit blocks and ended with a collection of modules that could be combined to performed a function like receiver or transmitter or test equipment would be great. This just has the circuits without putting them together in a project but the explanation is good for beginners. Some of these are better than others and there are some errata, but overall pretty good for learning.

    I like the EMRFD book, but in my opinion it is not a good beginner book. It is kind of like an engineering notebook with the editors thoughts and ramblings and test measurements all jumbled together. It has good stuff and crap all mixed together and someone starting would have some difficulty navigating it. A far better book was the original W7ZOI Introduction to Radio Frequency Design which unfortunately is no longer in print.

    Rainbow tuner The kit is not available, but the design docs, schematic etc are here. Or even just the SWR bridge part is a useful QRP tool.
    http://www.njqrp.club/Rainbow/rb_home.html

    Clamp on RF ammeter
    http://www.ifwtech.co.uk/g3sek/clamp-on/clamp-on.htm

    Dummy load built from non inductive power resistors on heat sink. There are quite a few examples on the internet for this kind of project.
     
  10. KM4LKC

    KM4LKC Premium Subscriber QRZ Page

    Good point on the test equipment. Our group hasn't discussed this yet.
    Thanks for suggesting these specific items.
     

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