Amateur Radio Homebrewing Hack Chat

Working the world on a homemade radio

Wednesday, March 18, 2020 12:00 pm PDT Local time zone:
Hack Chat
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Charlie Morris (ZL2CTM) host the Hack Chat on Wednesday, March 18, 2020 at noon Pacific Time.

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For many hams, the most enticing part of amateur radio is homebrewing. There's a certain cachet to holding a license that not only allows you to use the public airwaves, but to construct the means of doing so yourself. Homebrew radios range from simple designs with a few transistors and a couple of hand-wound coils to full-blown rigs that rival commercial transceivers in the capabilities and build quality, and sometimes surpass them. Hams cook up every piece of gear from the antenna back, and in many ways, the homebrewers drive amateur radio technology and press the state of the art forward.

Taking the dive into homebrewing can be daunting, though. The mysteries of the RF world can be a barrier to entry, and having some guidance from someone who has "been there, done that" can be key to breaking through. New Zealand ham Charlie Morris has been acting as one such guide for the adventurous homebrewer with his YouTube channel, where he presents his radio projects in clear, concise steps. He takes viewers through each step of his builds, detailing each module's design and carefully walking through the selection of each component. He's quick to say that his videos aren't tutorials, but they do teach a lot about the homebrewer's art, and you'll come away from each with a new tip or trick that's worth trying out in your homebrew designs.

Charlie will join us for the Hack Chat this Wednesday to discuss all things homebrewing. Stop by with your burning questions on DIY amateur radio, ask about some of Charlie's previous projects, and get a glimpse of where he's going next. 

  • Hack Chat Transcript, Part 3

    Dan Maloney03/18/2020 at 20:09 0 comments

    Charlie Morris ZL2CTM12:47 PM
    I do reuse some stages, but more often than not I simply reuse the componts.

    Wa6ara12:47 PM
    Also, build the fittings jto support the pots, caps and switches using a 3d printer

    Charlie Morris ZL2CTM12:47 PM
    I don't tend to box up my rigs as I like to see the electronics.

    @James Finch - Aren't you tuck with FSK and OOK with the Si4432? IOW, no AM, SSB, or FM?


    Charlie Morris ZL2CTM12:48 PM
    Anyone played with the Teensy?

    Charlie Morris ZL2CTM12:49 PM
    Great little uPs. Very powerful.

    Wa6ara12:49 PM
    Everytime I start with a box on a build I end up in a corner with lack of space or trying to trouble shoot down in a hole

    Ben12:49 PM
    @Charlie Morris ZL2CTM - I have one in a half-built virtual subtractive synth on a shelf :)

    juggie12:49 PM
    started to when you were playing with SDR

    Trevor R.H. Clarke12:49 PM
    @Charlie Morris ZL2CTM I've been using teensys for a few years, great devices! haven't had a chance to play with the 4 yet but I have one at home

    Charlie Morris ZL2CTM12:49 PM
    Nice. They did a great job with that. The audio lib is really good too.

    James Finch12:50 PM
    @MS-BOSS I've been trying to be patient and wait and see what everyone else has done first. tinySA (HBTE, UHF Spectrum Analyzer (instructables) and the

    crun joined  the room.12:50 PM

    bl00p12:50 PM
    have you ever tried building software selectable filters, charlie? either with fets or relays

    Charlie Morris ZL2CTM12:51 PM
    The other hard part being here in NZ is getting components. I often have to ship them in from overseas, Especially toroids.

    juggie12:51 PM
    I suspect that we're all about to face that Charlie

    Charlie Morris ZL2CTM12:51 PM
    Yes. I did use some relays a while back to sw in and out caps for a BPF. It worked. I want to do it again for a 80/40m rug.

    Charlie Morris ZL2CTM12:52 PM
    I kept the inductance the same and varied the cap. The passband characteristics were a bit wonky, but it worked.

    MS-BOSS12:52 PM
    Usually, a better approach than relays are PIN diode switches. At least these days.

    Are there special considerations in sending RF through relay contacts?

    crun12:52 PM
    @Charlie Morris ZL2CTM Do you have a known god aliexpress supplier of toroids?

    James Finch12:53 PM
    @Dan Maloney Still researching and compiling resource data. Have to review the code to understnd.

    MS-BOSS12:53 PM
    @Dan Maloney You don't want to send more than a few watts through relay at the moment it is trying to disconnect the contacts. Then you get a lot of magic smoke.

    Charlie Morris ZL2CTM12:54 PM
    For low level RF i have not had any problems with small relays. For high power yes. I tend to use either salvaged HF radio ant relays, or high current AC/DC relays. I havn't burned any contacts out with that approach.

    MS-BOSS12:54 PM
    @Dan Maloney For long operating life, cut the output power before switching the relay.

    Charlie Morris ZL2CTM12:54 PM
    Magic smoke. The key to everyhting.

    Charlie Morris ZL2CTM12:55 PM
    I get my toriods form Kits and Parts

    MS-BOSS12:55 PM
    @Dan Maloney Hermetically sealed relays with vaccuum inside are the best, however I have not seen them in years. At least not with sane price.

    @James Finch -Seemed to me when I read Silicon Labs data sheets on those chips is that they're geared mostly for transmitting and receiving data. They do make a line of FM broadcast receivers that output analog audio, but they're limited to the broadcast band 88.1-108MHz here in the States)

    Charlie Morris ZL2CTM12:56 PM
    As for AliExpress. I don't have any one specific supplier. I have been burned buying IRF510s. I only buy those through a local supplier.

    @MS-BOSS - Thanks for the tips!

    KD9KCK12:56 PM
    I got a SPDT RF relay with SMA connectors from a ham fest earlier this year. Going to use it for a TX/RX relay with my LimeSDR Mini. Depending on its power level.

    James Finch12:57 PM
    Are the transitor and diode switches worse at HF? Guessing...

    Read more »

  • Hack Chat Transcript, Part 2

    Dan Maloney03/18/2020 at 20:07 0 comments

    juggie12:21 PM
    Does that not come ith experience Charlie ... ?

    Charlie Morris ZL2CTM12:21 PM
    I don't mind using other peoples circuits, but I need to understand how they work forst.

    June12:22 PM
    That would be amazing.

    Charlie Morris ZL2CTM12:22 PM
    MS-BOSS. That's true, but good for 80m-40m I suspect.

    juggie12:22 PM
    Its informative to take a cap or an L and to try measuring it and understanding it - specially with more than one meter

    KD9KCK12:22 PM
    Some older radios have the area's marked out with white lines and labels. So its easier to figrue out what does what.

    Charlie Morris ZL2CTM12:22 PM
    What's that Juggle?

    juggie12:23 PM
    understanding a circuit properly

    bl00p12:23 PM
    yeah, i'd like to see some well documented impedance matching amplifiers that don't need transformers, like an IF amp that matches 50 ohm out of a mixer to 500 ohm crystal filter

    Tomi Piriyev12:23 PM
    Anybody has experience in getting CE /FCC for radio module?

    Charlie Morris ZL2CTM12:23 PM
    Yes. A lot of the HF manuals explain the circuit quite well.

    MS-BOSS12:24 PM
    SPICE is your friend, especially if you can get S-parameters of components as well as transient model.

    Charlie Morris ZL2CTM12:24 PM
    Juggle. Yes. I had a good foundation through the air force. The more you do the more you understand how the circuit works.

    James Finch12:24 PM
    @David I need to read into the latest and greatest. I'm a decade or two behind... spent most my time on FTNIR Interesting what can be made with lab test equipment also and with and for less now days.

    That's what I actually like best about Charlie's videos: here's the component, this is what it does, and here are the calculations that I used to figure out the value. Great stuff

    Gary Sutcliffe12:24 PM
    @Tomi Piriyev I ran a few RF modules through FCC.

    Trevor R.H. Clarke12:24 PM
    @Tomi Piriyev I suspect there probably isn't much experience with that here since the focus is homebrew which wouldn't require testing and cert

    Charlie Morris ZL2CTM12:25 PM
    Again, my approach is to keep tings simple. I'm trying to provide a resource back to the community.

    Ben12:25 PM
    @Charlie Morris ZL2CTM - would David Rutledge's "The Electronics of Radio" fall into that for you? I think it is basically walking through the design of a Norcal 40.

    June12:25 PM
    Yes, especially as a beginner, it's not like I know that measuring that component is gonna show me xyz. it's nice being able to read through (or watch) someone's thought process and why they landed on designing something a certain way

    Charlie Morris ZL2CTM12:25 PM
    I hope I do that June. That's the aim.

    Charlie Morris ZL2CTM12:26 PM
    I know the radios are simple and not 'contest grade' but that's the point for me.

    <h1> BSA </h1> joined  the room.12:27 PM

    Charlie Morris ZL2CTM12:27 PM
    I'ver a got a CW rig on the go here.

    newdendrite12:27 PM
    Contests are great test grounds for simple xmtrs :-).

    Tomi Piriyev12:27 PM
    @Gary Sutcliffe i would like to get CE/FCC certification for my Lora module

    Charlie Morris ZL2CTM12:27 PM

    Tomi Piriyev12:27 PM
    @Gary Sutcliffe i am wondering how long does it take and what price range?

    David12:27 PM
    @James Finch

    Charlie Morris ZL2CTM12:27 PM
    I'll build the receiver first and check out that HB filter

    juggie12:27 PM
    you can't beat bare copper and a hot soldering iron !!

    KD9KCK12:28 PM
    I need to get a better soldering iron. I can't get mine hot enough to solder to a bare copper panel.

    juggie12:28 PM
    use pads or me-squares

    David12:28 PM
    @James Finch there also nice paper on non-resonant amplifier and antenna design I could try and find for you

    Charlie Morris ZL2CTM12:29 PM
    TIme wise is hard to say. You can easily knock out an amp in an evening. Cost is not too bad either, especially with AliExpress. Probably well under $100

    de∫hipu12:29 PM
    @KD9KCK pre-heat it

    KD9KCK12:29 PM
    Hm use islands. Good idea.

    juggie12:29 PM
    old fashioned bread boarding at its finest -

    Ben12:29 PM
    @Charlie Morris...

    Read more »

  • Hack Chat Transcript, Part 1

    Dan Maloney03/18/2020 at 20:06 0 comments

    Wow, huge turnout today! Thanks everyone for coming to the Hack Chat! I'm really excited to welcome Charlie Morris (ZL2CTM) to the chat. I've been following his YouTube channel on homebrewing for a while, and I'm excited to learn all about the art of building your own gear.

    Thanks for getting up so early Charlie. Can you start us off with a little about yourself?

    Gary Sutcliffe joined  the room.12:00 PM

    kd2kw joined  the room.12:00 PM

    leon8boy112:01 PM

    Charlie Morris ZL2CTM12:01 PM
    Hi all. I got my licence back in 1990 while I was in the Air Force. I srarted as a Avionics tech then Engineer officer.

    Charlie Morris ZL2CTM12:01 PM
    The air force gave me a good grounding in electrionics.

    Charlie Morris ZL2CTM12:02 PM
    I have loved all things electronics from a very young age. Switches, lights, motirs etc.

    Trevor R.H. Clarke joined  the room.12:02 PM

    Charlie Morris ZL2CTM12:02 PM
    After 30 yesrs of service, i'm now in the Ndew Zealand CAA

    Charlie Morris ZL2CTM12:03 PM
    Is there anyone else here who enjoys homebrew radios?

    Trevor R.H. Clarke12:03 PM
    hey charlie, all your videos..helps keep me moving on my own designs and despite not always being the ideal design methods, your techniques are well explained and generally work

    juggie12:03 PM
    yes & I follow your designs too

    Wa6ara joined  the room.12:03 PM

    bl00p12:03 PM
    dunno if i am proficient enough to say i enjoy it, i admire it

    June12:03 PM
    Not yet as I'm still just studying for technician's license, but one day!!

    Ben12:03 PM
    @Charlie Morris ZL2CTM - I would guess quite a few of us. Me for one.

    Charlie Morris ZL2CTM12:04 PM
    I really rtry and keep the designs as simple as possible.

    Trevor R.H. Clarke12:04 PM
    curent HAM projects: GPS disciplined 10MHz clock, inexpensive 2m beacon for fox hunting, 6m ssb/ccw transceiver

    Charlie Morris ZL2CTM12:04 PM
    What i cannot really find is the underlying theory (maths i guess) for many of the published circuits. That's what i really want.

    Wa6ara12:04 PM
    WA6ARA here, yes, do a lot of building and also follow your videos

    Charlie Morris ZL2CTM12:05 PM
    Yes, GPS units for NZD2-5 is a great way to start.

    Jim Anderson12:05 PM
    More kits than building from scratch, but would like to reverse that.

    duwayne12:05 PM
    Working on several pieces of test gear

    juggie12:05 PM
    your math breakdowns of circuits are a real learning tool for me

    Shawn Hymel12:05 PM
    I have my license, but don't quite know what to do with it. I'm really curious to know what's possible for creating simple text-based systems that rely on CW bands (I don't know Morse) or bands that have been set aside for digital comms.

    Charlie Morris ZL2CTM12:05 PM
    Kits is a great way to start to see if you enjoy soldering. You acn then move into your own circuits.

    Ben12:05 PM
    @Charlie Morris ZL2CTM - What reference books you recommend for homebrew radio designers? I have an ARRL handbook and EMRFD, was wondering what you found useful.

    Rin joined  the room.12:06 PM

    Charlie Morris ZL2CTM12:06 PM
    Digital comms is exploding. There are som many types now that tyou should be able to find something that interests you. That the key.

    MS-BOSS12:06 PM
    RF electronics aren't that complicated unless one dives into designing really low noise circuits or tries to operate components near the borders of their stability regions.

    Charlie Morris ZL2CTM12:07 PM
    I use Solid State Design for the Radio Amateur, Wes Hayward and Doug DeMaw, ARRL


    Experimental Methods in RF Design, Wes Hayward, Rick Campbell and Bob Larkin, ARRL


    chibill12:07 PM
    I am going to try my best to get onto 40m using a band-pass filter I built and my LimeSDR Mini. Also trying to make a WSPR decoder / encoder using a Teensy 4

    Steve Bossert (K2GOG)12:07 PM
    @Charlie Morris ZL2CTM .... are you experimenting with anything LoRa related at the moment?

    Charlie Morris ZL2CTM12:07 PM
    Both are good, but again lack the maths. I suspect a lot if is experimental and trial and error....

    Read more »

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