Don't shout - WSPR

Homebrew WSPR TX using the brilliant open source code by Harry from Zachtek.
If you want the best, buy from Harry,  https://www.zachtek.com/

I tweaked Harry's code to suit my particular setup(s), initially with a scratchbuilt, single band Tx with GPS - about 200mW out on 40 metres on a 9v DC supply.

I then made a multiband unit using modules from QRP-Labs, including the Arduino shield, si5351 OCXO, relay switch kit and assorted LPF's that all plug into an Arduino UNO.

The OCXO si5351 makes it so much more stable and once warmed up, it doesn't drift - I must try it on 144MHz sometime...

Running at 9v DC in gives an easy 200mW+ on multiple bands, in my case, 4 bands (10, 15, 20 & 40).

It is easily programmed by Harry's excellent Windows software and once the initial settings are done, it needs no further configuration as all important info is taken from the GPS (time, locator etc).

It only needs reconfiguring if you change bands/LPF.

Armbian Linux on a TV box

Armbian on an Android TV box

Follow the 1st post here...

https://forum.armbian.com/topic/26978-csc-armbian-for-rk3318rk3328-tv-box-boards/

It's actually quite easy to wipe out the Android install and put Linux on it, just make sure to use one of the RK3318 flavours to 'burn' onto it.
I run in command line only, but it will run the desktop GUI as well, but it's pretty sluggish.

If you 'brick' it, short the 2 pins in last pic and power on and run multitool again

My post is on page 38 of above link

Chinese RF Power Meter

My Chinese RF Power Meter has self destructed itself !

It's pretty much as this...
https://www.aliexpress.com/item/1005003572858028.html

Simply powering it on one day and the Q2 transistor glowed and let out the magic smoke.

If you have any idea what the original component marking is, I would really like to know as I can't find any detail about this bit of kit. - see EDIT at end of this post.

Click the images to go 'supersized'

The position of Q2 is just below the LCD on the right side and I have circled it's position in red on the next image after removing the LCD - it's a 3 legged device, probably SOT23...

Close up images

Beneath the top left tin screen is an AD8318 detector + circuitry.

Anyone got the same meter and could read the ID on their existing Q2 chip or better still has a schematic?

Please leave a comment below or my email is good on QRZ.com

EDIT:

Testing the AMS1117 5.0 (5v regulator) it had failed and in failing it went input to output dead short, injecting 12v to Q2 - probably why it smoked!
Q2 is/was a 3v3 regulator and tracing the circuit, it's Vout pin is also connected to the 3v3 pin at top right of the board (big clue there!).  Q2's Vin pad is destroyed, but should be simple enough to 'hot wire' to C16.
So, parts are on order, it must be worth trying to save it for the price of a coffee?

3D printed loading coil for HF

 Using a 3D printer to make a loading coil for HF portable or static mobile operation.

On Thingiverse I found some files to download and make a loading coil, by VA3TNE, here
https://www.thingiverse.com/thing:2352109

It is designed to work with a folding 'tank whip' or  'Manpack antenna' or AT-271 folding antenna - Google will bring up some useful links.

I printed both the long and short coil versions and found the short coil best suited my needs as it loads the 'tank whip' anywhere between 40 to 10 metres, which is all I need, although the long coil will tune to 80 metres, but it is very twitchy down there.
The coil wire is 1.6mm stainless wire and the end fixings are 3/8in UNF stainless bolts and stainless half nuts and a brass nut - the long brass nut is for old car exhaust manifods and everything can be found on eBay UK and other UK internet sites.

Tuning adjustment is achieved by a sliding 'short' with fly-lead - I used a Stainless 'Jubilee' clip as opposed to the original idea of a 'crocodile' clip, which is why the coil form has 5 vertical cutouts to facilitate the use of a crocodile clip.
The Jubilee clip is tightened enough to just allow it to slide up or down, but not so tight as to clamp it.

I had a broken camera tripod, so dismantled the broken head and 3D printed a bracket to mount the coil and some radials/counterpoise.  There are 3 short fly wires on the tripod mount and have gold plated 2mm 'bullet' connections for each of the radials, so they easily pull out if someone steps/trips on a radial and easy to disconnect and coil up for transportation.

How it looks on the tripod for portable work (click the images to supersize)

On top of the car with mag-mount

Long loading coil

Short loading coil - my preferred option

The whole package ready to deploy - takes just a few minutes.

I also found that M1ECC is marketing his version of a very similar coil, under the name 'slidewinder DX', here

(Link removed at request of M1ECC-Antennas --> see M1ECC Antenna comment below).

He sells the folding whip seperately, although I got mine from China.

Used 'Carbide Create' to make a simple 'schematic' for machining a PCB for a G3UUH style Crystal Oscillator/Crystal Checker.

The end result is quite pleasing (click the images to go supersized)

    

Seems to be working OK

Watch the machining process

Direct link to YouTube
https://youtu.be/Htc-WbQEaBo

CNC machining 'pads' on a CNC3018

I needed a circuit board for a TVI filter to stop 2 metre interference, like this (I'm going for the 144 and 432 MHz layout)
http://www.vk3nx.com/TVIfilters.html

I used 'Carbide Create' to 'draw' what I required
(Click the images to go supersized)

Then, added Toolpaths to machine outside of the darawing/pads

Set the cutter, depth, speeds/feedrate etc and save the GCode.

Load the gerber into 'Candle' and probe the PCB for a heightmap.

Set it off with a 1mm end mill and the board was done cutting in 45 seconds!

Quite please with the result - hope it works when finished assembling!

Fully assembled and tested, over 83db of attenuation at 145MHz and 45db at 433MHz

CNC Milling PCB Manhattan style solder pads on cheap CNC 3018 machine

I recently bought a cheap CNC milling/engraving/laser cutting machine - a CNC 3018 Pro as it was advertised locally for less than half the cost of new and hadn't been used for an hour as the owner just couldn't get on with it, hence the sale, much as this one...
https://www.amazon.co.uk/dp/B08P5WPDLP

I'd like to use it for milling PCB's and maybe for milling panel cutouts and possibly engraving them.
First test was to make some Manhattan Style solder pads and after some rapid learning of software, the first panel came out quite well.
Cutter is a 1mm end mill and 3 passes at 0.4mm cut depth to get to 1.2mm deep cut makes it easy to score through with a sharp craft kinfe/Stanley knife to get the bits required.

I stuck the board to the 'waste board' on the mill bed with 13mm wide double sided tape and used 'Candle GRBL controller' and it's height map facility to send the code to the machine.

It's quite easy to pry off by sliding an old putty knife under the board and then pick the tape off - didn't even need cleaning off with IPA or similar.

Short video of it in action (it's nowhere near as noisy as the camera makes it out to be).