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Hack Chat Transcript, Part 1

A event log for Amateur Radio Homebrewing Hack Chat

Working the world on a homemade radio

dan-maloneyDan Maloney 03/18/2020 at 20:060 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
Hallo

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, K8TRC...watch 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

and

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

mainly.

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.

Shawn Hymel12:07 PM
@Charlie Morris ZL2CTM any good recommendations on projects, books, or sites (other than your channel, which I just subscribed to) that could help someone get started with digital comms projects for amateur radio?

James Finch12:08 PM
Working my way up the learning curve with some test equipment repairs/hacks to get started with so no unintentional emissions. Then some test equipment builds. Then I'll modify those for listening/monitoring with the other receivers and SDR's.

Charlie Morris ZL2CTM12:08 PM
No not LoRA, but I have been reading into it. I tend to like things that have utility and I can use for something.

Trevor R.H. Clarke12:08 PM
I'm also planning on building a very small, very low power FT4/FT8 device for 40/20m that I can keep in my pocket at all times

chibill12:08 PM
^ That would be neat.

Charlie Morris ZL2CTM12:08 PM
Digital comms. There are some good channels on YouTube, but I must admit i cannot recall them now.

Arthur joined  the room.12:09 PM

Trevor R.H. Clarke12:09 PM
probably will use a teensy 4 or maybe a small FPGA for the maths

Charlie Morris ZL2CTM12:09 PM
FT8 is another interesting mode.

Trevor R.H. Clarke12:09 PM
@Charlie Morris ZL2CTM I believe you travel to the US relatively often for work? Are you ever on-air while here?

Charlie Morris ZL2CTM12:09 PM
The Teensy range is great, Very powerful and a great audio library. Especially for SDR

bl00p12:09 PM
i haven't watched all of your videos, charlie, but the ones I have seen you don't really talk about your antenna setup, and i see you always seem to be able to receive things even without much going on in the preselection filtering setup so i was wondering about what kind of antenna you have

chibill12:09 PM
Yea. Seems to be the only thing that really propagates on 6m recently.

Shawn Hymel12:09 PM
@Charlie Morris ZL2CTM Cool, thanks! I'll search for them.

Arthur12:10 PM
this one of the best books I've found: Communications Receivers: DPS, Software Radios, and Design, 3rd Edition (McGraw-Hill Telecommunications) by Ulrich Rohde

Steve Bossert (K2GOG)12:10 PM
@Charlie Morris ZL2CTM . Thanks. Application/use driven is really key for any project..... Its always interesting when "amateur radio" , "ham radio" and "maker" people approach projects differently either by trying to find a use for a specific technology or find a technology for a specific use case.

Charlie Morris ZL2CTM12:10 PM
Yes I do tavel to the states often for work. At this stage i have not looked at getting on air. That's probably a good idea though.

Charlie Morris ZL2CTM12:10 PM
Thanks Arthur. That looks interesting.

June12:11 PM
I've actually found my previous attempts to get into building/making have fallen flat BECAUSE I didn't have a specific use I wanted to learn for. Ham radio has completely re-invigorated me wanting to hop into building again.

Charlie Morris ZL2CTM12:11 PM
AliExpress is also a great source for components. Just not BJTs and FETS!

Charlie Morris ZL2CTM12:11 PM
I have had several of those blow up in my face.

chibill12:11 PM
I have been working on attempting to push a CB to 10m to get on the air.

MS-BOSS12:11 PM
I believe that asking about a book for "amateur radio" or "digital comms" are too broad questions and indicate that maybe you could grab some basic book like the art of electronics by Horowitz and Hill which is not specifically oriented at radio. Maybe if you were asking about specific issues like "balanced mixers", "demodulation techniques for FM", you could get a specific answer.

Remember all - I'll post a transcript of the entire chat soon after we wrap up. No need to scramble to copy down links and such.

Charlie Morris ZL2CTM12:12 PM
June. That;'s the key. find something that interests you and get into it. Ham radio has so much to offer in that regard

Charlie Morris ZL2CTM12:13 PM
chilbill. How is that going?

SimonAllen12:13 PM
What is the topic for tonight?

Charlie Morris ZL2CTM12:13 PM
I have a couple of old marine radios here that I have transplanted Si5351s into. They work well.

juggie12:14 PM
that raises an interesting point about just getting an Si5351 working as a component ...

@chibill - Love to hear details on that. I too was looking for an old SSB CB to convert, but the secondary market is pretty thin

Steve Bossert (K2GOG)12:14 PM
oh!! lets talk about the Si5351...so many cool things you can do with that.

juggie12:14 PM
then adding mixers and rf components, decent audio etc ...

Charlie Morris ZL2CTM12:14 PM
I tend to use the Si5351 board with the I2C interface.

Ben12:14 PM
@MS-BOSS - my specific thing I was currently looking at was around tweaking a class b, transformer coupled push-pull bjt qrp final PA. Any thoughts around a book for that?

chibill12:14 PM
First attempted sort of failed because I forgot to make sure the radio actually worked at first. Haven't started on the second try with a different radio. (This one had mods from someone else)

@SimonAllen - Homebrewing ham radio

MS-BOSS12:14 PM
A slight tip: Si5351s VCOs can be tuned from about 150-200 MHz to about 1100 MHz. In this range, the PLL works OK, although jitter may increase.

newdendrite12:15 PM
Using si5351 to drive qrss xmtrs here.

Arthur12:15 PM
if you into VHF/UHF then this is a classic: VHF-UHF Manual, by G.R. Jessop, published by Radio Society of Great Britain

James Finch12:15 PM
@SimonAllen Charlie Morris who has a youtube channel and blogger with a lot of detailed designs he built and shows is on. https://www.youtube.com/channel/UCSNPW3_gzuMJcX_ErBZTv2g/videos

chibill12:15 PM
Si5351 are very nice chips / devices. Mine doesn't seem to work well when feed with 3.3 volts.

Steve Bossert (K2GOG)12:15 PM
you can make a WSPR beacon out of a Si5351.... This is a good example of something that take it to a different level.... https://www.qrp-labs.com/lightaprs-w.html

Charlie Morris ZL2CTM12:15 PM
Some great texts there. My main interest is HF for some reason. It's certainly easlier to design for.

Doug joined  the room.12:16 PM

James Finch12:16 PM
Blogger: https://zl2ctm.blogspot.com/

@MS-BOSS - Does that mean you could use that chip to build a 2-m band FM receiver? Because I really need to do that.

Shawn Hymel12:16 PM
@MS-BOSS That's fair, but I'm not too interested in digging too far into the theory. I'm looking for a basic starter project that someone could implement to start tinkering with digital comms over ham bands. Because I don't know much about amateur radio, I wouldn't even know what to ask when it comes to specific issues (at least until I start tinkering with some beginner project and started to learn more about it). It seems like watching people's builds on YouTube might be the way to go for that, as per Charlie's recommendation.

MS-BOSS12:16 PM
Si5351 need to have properly decoupled power lines and crystal with low capacitance. See AN551

Charlie Morris ZL2CTM12:16 PM
Steve. I did that a while back with the AD9850. It worked really well. It just sits there doing its thing.

MS-BOSS12:17 PM
Yes, you could... maybe. However, the Si5351 output is not guaranteed over 125 or 150 MHz, not sure right now

juggie12:17 PM
That belies the hassle of getting a VFo working Charlie !!

MS-BOSS12:17 PM
However, be aware that it emits square wave

Charlie Morris ZL2CTM12:17 PM
Shawn. I'd get myself a radio and interface your computer to it.

David12:17 PM
@James Finch its 42. 58 mhz per esla

Gary Sutcliffe12:17 PM
I made an si5361 WSPR Beacon for 630 meters. Running about 12 W to a short 1% efficient antenna it has been picked up in Hawaii from here in Wisconsin – W9XT

newdendrite12:17 PM
Solid State Design for the Radio Amateur Paperback – great text for learning homebrewing.

James Finch12:17 PM
Any thoughts of using the Si4432's? I suppose need two to mix to the diffrence frequency for lower range use.

Trevor R.H. Clarke12:17 PM
@Dan Maloney 2m can be a little trickier to deal with as the frequency is high enough where you need to be careful about parasitic capacitance etc on your boards, but you can do it...there are a lot of components out there to make it much easier these days including VFOs

Charlie Morris ZL2CTM12:17 PM
Agreed. I stared many years ago with simple ocs and NO o'scope. Very hard to do.

MS-BOSS12:18 PM
However, you can use the Si5351 as 2m radio if you use some higher harmonic of the output which is utilized in NanoVNA.

@Trevor R.H. Clarke - Thanks!

Charlie Morris ZL2CTM12:18 PM
Having a ok scope and sig gen are key for me here. Being able to see the signal/waveform is so important.

David12:18 PM
You can build a pretty smooth field with permanent magnets up to about 1 tesla

Charlie Morris ZL2CTM12:19 PM
The NanoVNA is another useful bit of kit. Quite cheap too.

chibill12:19 PM
I have a 20 Mhz o'scope and also a NanoVNA. No good sig gen. Was going to use my SI5351 as a sig gen for testing stuff.

David12:19 PM
That's usually small though

newdendrite12:19 PM
Any links or tips for reprogramming the NanoVNA for other ham applications?

juggie12:19 PM
lots of material on the NanoVNA around on the web - watch G-QRP for contributions from Tony G4WIF

Charlie Morris ZL2CTM12:19 PM
I'd filter the Si5351 to make it a useful sig gen. I nice clean sinewave.

MS-BOSS12:19 PM
Have a look at ADF4351 or MAX2870 for cheap microwave signal generators. Square wave, again.

Ben12:20 PM
@Charlie Morris ZL2CTM - are there any homebrewing resources that you wish existed?

David12:20 PM
I'm aiming for about 0.1-.2 Tesla, so somewhere between 4 and 8mhz

Charlie Morris ZL2CTM12:20 PM
I had the same question re the NanoVNA. The base software is good, but freq entry is lacking.

David12:20 PM
But I'm not an RF guy

Shawn Hymel12:20 PM
@Charlie Morris ZL2CTM Good idea! I'll look at getting a rig for that. Thanks!

Roumen12:20 PM
Charlie Morris, what o'scope are you using?

David12:21 PM
I need fast switching gdrtom TX to RX

Trevor R.H. Clarke12:21 PM
@chibill if you can afford a little bit, there are lots of halfway decent sig gens using DDS you can pickup for well under $100 USD. They make decent sine and triangle waves which is important for a lot of applications. The si5351 generates a square so you'd need to do some filtering to use it as a sig gen

Tomi Piriyev12:21 PM
anybody has experience getting CE certification for RF transiver?

MS-BOSS12:21 PM
If you filter the output of the Si5351 or other square wave generator, then you have tuning range less than 1:3, because then the higher harmonics get through the filter.

Charlie Morris ZL2CTM12:21 PM
Ben. Yes. I'd like more theory based resources. I love being able to see all of the components in a radio and know what each component does.

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