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).

 

It's Radio Jim, but not as we know it!

I installed the new/beta DVPi on a Raspberry Pi2, added a 3.5" TFT touchscreen, cheap USB sound card, speakers and Microphone, linked it with DVSwitch and now have a functional DMR transceiver!
Yep, that's it, no radio required, it all runs on the R-Pi and software.
Total cost if bought new, probably less than £50, but I just happened to have all the required items anyway so gave it a shot.
It will run without the 3.5" screen and output is via HDMI and a large screen/TV.

I just need to make an adapter for a few simple controls rather than prodding the small screen with fat fingers (PTT, volume and channel control etc).

Comes courtesy of some very innovative work by Ian, KD8CEC

http://www.hamskey.com/

Fibreglass pole vertical

I've been playing about with a reasonably heavy duty 10 metre fibreglass pole (squid pole/roach pole).
A problem with these poles is their tendency to collapse, always at the wrong time!
I fully extended mine and drilled a hole near the top of each section and 3D printed some 'C clips' (or is that an E clip?) with a moulded pin to insert into the pole...
(as always, click the pics to go supersized)

Mk 2 clip with an external 'eye' to thread a wire through to stop it flapping about in the breeze!

Now, the pole stays extended and doesn't collapse.  It's a simple matter of prying off the C-clip and collapsing the pole.  Extending it and aligning the pin holes is a little fidgety, but still easy and makes for a snag free, quick to erect pole.
Bends quite a bit in 25+ MPH wind - guys are next on the agenda.  You can see each C-clip up the pole!

I also found a 3D printable 'DX Commander' style base plate allowing operation on/upto 4 bands with a single coax feed...

I'm awaiting delivery of some stainless hardware to finish it off.
To be continued....

USB VFO for SDR

I bought one of those USB audio control knobs and reprogrammed it as a VFO, as per instructions here

https://tysonpower.de/blog/reprogramming-a-audio-knob-to-build-a-sdr-vfo-knob

It does work as a VFO, but as standard the encoder has detents which doesn't make for 'free running' rotation.

So, de-solder the encoder from the PCB, strip it and remove the little detent ring, re-assemble it, solder it back and now it feels much nicer to rotate with just a finger tip (you can see the little detent ring in the pic below, beside the USB/serial adapter).  The knob is a push fit on the splined encoder shaft.

It does work, but it is basically only a VFO spinner with long press of the knob to mute audio.

To re-programme it, I simply soldered a jumper wire from 3v3 to pin1 (as in the link above and then removed it after programming) but used a 4 pin header 'wedged' into the holes on the PCB adjacent the USB connector wired to an FTDI USB to serial converter for 5v/GND/Tx/Rx and held the header over by hand to make contact during programming.

It was a bit of fun to do, but as it stands, doesn't do much more than the scroll wheel of my normal mouse in Quisk and I wish I knew something about software to be able to maybe take it a step further as in adding another encoder for audio volume and possibly another button or two...

Click the images to go 'supersized'

It looks as though there are some pins available on the chip and the code could be tweaked - if only I knew what I was doing !!

Sure would be nice to get at least audio volume up & down at the least.

Anyone up for a coding challenge?

7 MHz interference

I've recently been plagued by some 7 MHz / 40 Metre interference.
Below is a screen grab from my SDR radio showing just how strong and wide the signals are.
I suspect VSDL and video streaming, but can't be sure.
During weekdays it usually starts late afternoon/early evening and at weekends, just about anytime.
Have you seen/experienced anything like it?

Click the image for a larger view...

I made a short video of the offending QRM, watch it on YouTube here:

https://youtu.be/38azPKt3mGo

Might be the 'Kontayner' OTH radar from Russia?  2nd one down, here:
https://www.sigidwiki.com/wiki/HF