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Thread: Need some information

  1. #1

    Join Date
    Apr 2018
    Location
    California
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    Default Need some information

    Hello everyone,
    I am new to electronics and ham radios.
    I want to build my own transceiver but I'm having trouble understanding how it works, does anyone have a block diagram of a transceiver? Also I know the rf signal has to be combined with a carrier signal, how is this done and what components are used in that circuit?
    Thank you for the help

    Sent from my SM-N950U using Tapatalk

  2. #2

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    The first one I built had .5W output, on a single channel and was a huge learning experience. The killer things for me were that some of the things I had to do were make inductors by following physical instructions because I had not ability too measure their inductance, so the plans I was using were very detailed.

    There is NO WAY I could have built one from a circuit diagram. You also have a huge way to go on the theory. The carrier wave is RF, you are thinking about how to add the content - as in perhaps voice or maybe data, and this can be FM, AM, or SSB, so you have the subjects of deviation, modulation and side band suppression to get into your head before you even think of building one. I assume you can solder, and the technical theory of radio operation? You also have to consider what band - are we talking about HF, or VHF or UHF? A block diagram helps understand what each module does. Often, the transmitter is the easier suction, and the receiver the real tricky one because small Mal adjustments mean it is deaf, or doesn't receive where you want it to. The transmitters often involve multipliers - so it actually oscillates on one frequency that gets multiplied by a fixed figure to provide your out on another, but then of course you need filters to remove the earlier stages.

    I think that after all these years I could still build one from a decent kit, with decent parts - but it's a huge task to the first time builder, even from a kit. From just a circuit, I suspect impossible.

    I'd start on the technical learning first - as you are in the US, see if you can source (even a second hand copy) of the ARRL Handbook - this will cover what you need to know, but be warned, this is NOT easy reading, and totally beyond what we can teach you on here. Perhaps Google your local radio club and talk to some hams who have done this kind of thing. Be warned, they will probably tell you it's going to be hard work, and probably scarp before you finish. You also need some basic test gear.

  3. #3

    Join Date
    Apr 2018
    Location
    California
    Posts
    4

    Default

    Quote Originally Posted by paulears View Post
    The first one I built had .5W output, on a single channel and was a huge learning experience. The killer things for me were that some of the things I had to do were make inductors by following physical instructions because I had not ability too measure their inductance, so the plans I was using were very detailed.

    There is NO WAY I could have built one from a circuit diagram. You also have a huge way to go on the theory. The carrier wave is RF, you are thinking about how to add the content - as in perhaps voice or maybe data, and this can be FM, AM, or SSB, so you have the subjects of deviation, modulation and side band suppression to get into your head before you even think of building one. I assume you can solder, and the technical theory of radio operation? You also have to consider what band - are we talking about HF, or VHF or UHF? A block diagram helps understand what each module does. Often, the transmitter is the easier suction, and the receiver the real tricky one because small Mal adjustments mean it is deaf, or doesn't receive where you want it to. The transmitters often involve multipliers - so it actually oscillates on one frequency that gets multiplied by a fixed figure to provide your out on another, but then of course you need filters to remove the earlier stages.

    I think that after all these years I could still build one from a decent kit, with decent parts - but it's a huge task to the first time builder, even from a kit. From just a circuit, I suspect impossible.

    I'd start on the technical learning first - as you are in the US, see if you can source (even a second hand copy) of the ARRL Handbook - this will cover what you need to know, but be warned, this is NOT easy reading, and totally beyond what we can teach you on here. Perhaps Google your local radio club and talk to some hams who have done this kind of thing. Be warned, they will probably tell you it's going to be hard work, and probably scarp before you finish. You also need some basic test gear.
    You are correct on my lack of theory, I have a lot to learn. Thank you for your feed back I just downloaded the 2011 ARRL handbook, figure it's a start.

    Sent from my SM-N950U using Tapatalk

  4. #4

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    The cleverer than me friends I first got into ham radio built radios, and without doubt they were clever people but the radios were basic, and by today's standards, let alone those of the 70s/80s, they do so little. If your interest is in the making of things, then they can be good fun to do - but operationally, they offer little satisfaction. While the basics of how the transmitters work make sense, and even ion your filtering is dreadful, you might get across the world on one - and be blissfully unaware of the chaos you cause to other users with your badly suppressed spurious signals. Receivers, however, can be again simple to build to listen to a bit of short wave stuff, but with the crowded bands, even finding a frequency can be problematic. Lots of builders used a tuning dial that had micrometer style readouts, and by using established short wave broadcast stations could build up a table. 31.55 on the dial was 3.41KHz, and 39.2 was 3.9KHz and so on - then you could stab a guess where your licenced bands would be - but then the damn things would drift as they warmed up!

    The upshot is that building is one hobby and operating a very different one. Both are fine, but you will never build a radio of the standard of the simplest and cheapest commercial one. This is fine - if the pleasure comes from the smell of burning flesh when you soldered your finger tip. It's a kind of long term challenge.

    If you read and digest the book - you'll also find that the section on antennas makes a huge difference too. Some is hard going, but if you read and understand the content, you will be a more practical ham than many.

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