Showing posts from 2021

The QYT KT-7900D

But is it any good? As you might have noticed, I am now a freshly licensed radio amateur .  As such I do need a transceiver or two in order to get on the air.  This is the story of one of my new radios. I have a limited discretionary budget to use for my new hobby, and I have to say from the outset that my lovely wife has been very supportive.  As such, I want to try and get the best value for our money.  One evening I stumbled upon this little item on Banggood for a little over $A150 including shipping.  Covering both 2m and 70cm bands with a claimed 20W output it seemed almost too good to be true.  I bought one. About ten days later a tiny package arrived for me.  At just 98mm x 43mm x 126mm the photos don't convey quite how small it actually is.  The entire case serves as a heatsink so it is heavier than it looks, but certainly not bulky. The standard power cable comes with a cigarette lighter plug.  As I intended to run it from home using a regulated PSU, I just cut the plug o

DIY feed-through panel for your antenna cables

DIY feed-through panel for your antenna cables I'm fortunate that I have a nice warm space inside to use as my "shack", but logically my various antennae are outside, so how do I get the cables from the antenna to my radios?  I don't want to go drilling holes in walls etc. because that would make me very unpopular with my wife and it would also invite leaks, drafts, pests and other generally unwanted things. Since I have a large window near where my gear will be located, I hit on the idea of making a filler panel and then attach a bunch of connectors to it.  Naturally I wanted it to look as nice as possible. The only modification to required to the window is to remove the insect screen.  In my case, this is fine since we never open this window anyway.  Otherwise you may consider making up a narrower screen. The window closes up on this panel holding it in place and keeping everything sealed up. I chose bulkhead connectors because I don't need to solder any connect

Ham: without the sandwich

 Ham: without the sandwich   My wife loves to call me "a bit of a ham" , and I am proud now to say that she is right.  Herein lies the story: Somewhere around 1976 I was a boy scout when I attended a Jamboree Of The Air at the home of Lyle Patterson (VK2ALU) in Mt St Thomas in Wollongong.  I think that the furthest contact was New Zealand, but most contacts that day were actually around the Illawarra.  Nonetheless I was amazed by this concept.  I could have my own transmitting station and talk to anyone, anywhere?  Sign me up! Turns out that in those days, it was not so simple and the idea of learning Morse Code, even at 5 words per minute scared me off.  Yes, I could have gone for the "Z-Call", which did not have this requirement but I wanted to reach the world, and this meant HF.  The idea got shelved because school got in the way (and having no money was also something of a concern) but I did get involved in building and restoring plenty of receivers over the yea

Wasting your and my time

I had a really interesting experience recently which I hope might enlighten others as much as it did me: I was approached (via LinkedIn) by a recruiter from one of the big tech firms, as they put it "based on the work you've been publishing on image analysis and learning models".  I would have to admit that doing this kind of work for one of the holy trinity sounds like a dream job for a hardcore geek like myself. So I went along late one afternoon (they kindly offered to meet with me at their premises in town at the end of the day to allow me to focus on my current job).  To be completely honest, I am happy where I am, but what's the harm in hearing what they have to say, right?  What they had to say was truly fascinating. After the usual niceties, we got down to my professional history.  " I see you've been working in the technology industry since the early 1980's.  That must be a misprint right? "  I briefly explained the somewhat circuitous path

Resuscitating a Scooba

  I am not 100% sure where this is going, but it's going to be a fun journey...   I own an iRobot Roomba 630 floor cleaner, and it works well enough for our house.  But I discovered the iRobot "Create" which is designed for teaching and hacking in general.  As you can imagine, repurposing our cleaning robot for my hobby might not sit too well. Using the local social networks, I picked up an iRobot "Scooba" for nothing.  According to the previous owner, it won't charge and the power light glows red when you plug it in. I downloaded the service manual from one of those manuals websites, and learned this is likely to mean that the battery has failed and won't hold a charge.  I figured I could probably re-pack it and things would be sweet. As with so many of my projects, the problem was a little more complex than I expected.  The reason why it won't charge is that the battery was missing, rather than simply faulty.  Given it's a specialised package,

OpenCV and CUDA - updated build notes

Yes, this comes up a lot, and if you're getting mysterious build breaks, maybe it's a mismatch between what version of gcc/g++ CUDA requires, your default compiler. The symptoms are that cmake completes just fine (so it found a compiler, all the libraries, etc) but then you get a "failed to compile" error when you do a "make -j[number]" The first thing to do is to run a single-instance make, because the errors will likely be less obtuse.  When I did this, I got: "error: #error -- unsupported GNU version! gcc versions later than 8 are not supported! " gcc --version told me it was version 9, so there's the problem.  But how to get around it? Make sure you have a suitable version of gcc and g++ installed (version 8) in our case.  On Ubuntu, you can do this with: "sudo apt install -y gcc-8 g++-8" Tell cmake about it when you do the pre-build with: "-D CMAKE_C_COMPILER=gcc-8 -D CMAKE_CXX_COMPILER=g++-8" To wrap up, the cmake comm