Nano VNA

Ok, so these are my initial thoughts of the device. Firstly, the only issue I have so far is that Windows does not always detect the USB device. I am not sure exactly what the issue is, low voltage, USB drivers kind of flaky or what. But powering it from an external 5v supply the device turns on every time. So i think its windows and computer related, not the device.

On to testing. Not a lot of time today to do anything flash, so I ran a bunch of S11 measurements on things i had handy and the plots were as expected. I do not really have anything here to test in the upper frequency ranges, being a HF kind of guy, but on measurements up to say 100meg, where I have the ability already to compare against another tool, the measurements look legit to me.

First up, calibration is easy and it comes with open, short and 50ohm loads to calibrate to, apparently I have the 900meg firmware installed, if i can work out how to change that to use the 300meg firmware I will. I dont need to measure beyond a couple hundred meg at best anyway.

First up to be tested was the Tri-Band vertical. Yes it is poorly tuned LOL and the SWR plot is correct. LOL I need to fix that 😉

This is the smith chart for the tri bander.

And this is what the LCD screen is showing while testing the tri-bander.

Next cab off the rank was my home brew dummyload. I knew already it was good out to about 100meg, but did not think it would be fine out to 300. Guess i did ok with a handful of resistors LOL

Next up was a 70cm antenna off the MD380 DMR HT. Now i have no idea how accurate this is, but it looks like what you might expect to see with a dip where it is meant to be.

And this is what the device was displaying while testing.

All in all, so far for S11 measurements the nanovna has done exactly what it was designed to do. I was a little surprised that it is as accurate as it is. This is not a very expensive tool at all, like $90 Australian delivered from ebay. Add this in with the rest of my cheap test gear and I have a good selection of gear for not a lot of dollars. When i get some time I will do some 2 port measurements and see how it goes. I expect it will perform quiet well. Bring on the filter testing 🙂



After reinstalling the server OS and restoring my backups there are always a couple of things that never work quite right again and need me to manually go in and change things. MySql database password is one and I can to that in my sleep, but something new this time is that the website is now SSL enabled with a Comodo SSl certificate. For some reason and I am not sure exactly why, restoring the backup borked the SSL implementation. I tried to find a fix for it for a couple of days and nothing that I did would fix it. So it was stuck in the to hard basket for another day. Well, yesterday I just removed everything SSL from the server and started from the beginning and got a new certificate issued. It all seems to be working now. Who would have thunk it, computers just never want to play nice HAHAHA.


Straight Key All Pretty Like

A good mate of mine is in the process of cleaning out a lot of stuff that he has sitting around, not being use and gathering dust. He offered me the Speedy X key at a price i could not resist. It was unused, new in the box. And the key itself is rather smooth and I like it, so today I had a couple of hours free and decided to put it on a base.

I did think about using some exotic hardwood like Padauk or Black Bean, but after searching about for a small block that was suitable, it became apparent that it was going to be a non starter unless i lucked onto a bit. So, in the garage I have some eucalyptus branched that my wife brought home for me to cut up and make into toys for her kindergarten kids to play with. Its been sitting there drying for months now, so i grabbed out one of the bigger bits, cut a diagonal off it to get more surface area and began sanding away to get it looking pretty.

I did not know if it was going to look all that good, so initially i sanded back one side just enough to make its kind of smooth, well as smooth as 80 grit is going be be and gave it a coat of oil. I knew then that I liked what I was looking at and proceeded on.

Not having access to a thicknesser, all i had was the belt sander to use, so I set about sanding the sides to be parallel to each other. The image above I am just checking to see that the overall visual is going to be what i was after.

More sanding and then even more sanding. Eucalyptus has a density of something like 800, so its very very hard. It took about 90 minutes of sanding to get the base to this stage. Once i had the shape I was after, i proceeded to go down the paper sizes to remove most of the sanding marks. 80, 240, 400, 800 and 1000 grit papers in all.

After what seemed like an eternity sanding, I hit it with some wax and gave it a good buffing. I know not everyone is going to like this kind of base. I call it, city meets country. You have the formal and structural elements of how many make their bases plus the informal in that it still looks like a tree. Ying and yang if you like, its very much like who I am.

This is the underside of the base. I think its a very pretty wood. I am very pleased with the result and that the timber is still very natural looking. Sure the key might also look good on some exotic hardwood that has been french polished to within an inch of its life and glows in the dark, but this is very Aussie and that will work for me.


Why, Why Windows 10?

I really don’t know why microsoft really wants to screw things up all the bloody time. This morning i wanted to burn a raspbian image to a sd card to fire up a new Pi i have that I am using in an project i am working on. And you would think something as simple as stick disk in slot burn image wold work. NO NO NO. Windows has been upto its old tricks and changed all the bloody device drivers so that my card reader no longer worked. After dicking about for 30mins and swearing profusely, I did some google foo to see if there was anything known going on. A quick driver roll back and boom we are back in business and have the Raspbian being written to disk. WOOP another tragedy in the making and total disaster avoided. HAHAHA Microsoft, what a steaming pile of turds. And before any of you linux fan boys comment saying oh just use linux, I can’t because i need to run some proprietary windows software for work as well as some other software that has no real linux replacement that will not work under linux and wine.


Well that went surprisingly smoothly after windows wanted to be a dick LOL


SETI at Home

So what seems today like 500 years ago I got involved in the Seti At Home Project. Actually i got involved not long after it first started with my initial sign up date being the year 2000. Horay for the stats they keep. Anyway, while chatting with some friends, I was reminded about Seti and that it has been a long time since I had even thought about it. So i downloaded the client and fired it up and have let it run in the background of my computer ever since.

I have always been a bit of an astronomy fan boy, particularly radio astronomy and being a radio fanboy and homebrewer of sorts, Seti is a pretty good fit. Its funny, back in 2000 I think i was running a 486 and it took a day to process a data block, now with a fancy GPU in my office computer I am processing a data block every hour. Havent computers gotten faster.

And its not just aliens you can give up your computer processing time to. The science united project that also uses the Boinc client has plenty of other scientific projects that could use the help of distributed computing methods to crunch the data. So if you got a buzz for science check them out and give them a go.


ITS ALIVE!!!!!!!!!!!!!!

Well it actually happened. The flaky server actually died yesterday. Tech support had the motherboard replaced in short order but for some reason the OS kernel was not happy with the change and would not boot. I dicked about with it for an hour or so and still could not make it happy. So, it was put in the to hard basket and i got up early today, reinstalled the OS and restored a backup of my data and we are back online. I am missing a couple of posts because I was lazy and did not download the last backup, but hey, its a personal blog. A few posts missing is not really going to mean much. Anyway, i should now be back in the land of server stability and should not have any more issues.


A New Linked Dipole

So for the longest time I have been using a Sotabeams linked dipole. Its been broken and repaired a number of times, but its getting to the end of its life. The links are more rust than metal, the centre has been broken and repaired a number of times and replaced, the coax and antenna wire has nicks in their sheaths. So rather than repair it or replace it, I decided it was time to build a new one from scratch. I have assembled the parts, RG316 coax, teflon wire and a sotabeams winder kit and parts. Will make it for 20, 40 and 80.