More to come...

Who is ZL2PD?

For anyone remotely interested in the person behind this website, a few more details can be found here.

Email ZL2PD?

Links to other websites:

Logging the Changes:

19.11.16: Some minor maintenance updates. Corrections here and there, and a few minor changes - Most notable, a new PCB layout for my multi-feature si5351a VFO (and some notes about a minor schematic error - Oops! Sorry!)

20.8.16: Updated several pages, added new Nighthawk, aviation rx, xtal checker, cardboard LC meter and 8-digit counter box projects.

7.3.16: Added source code files and a bit more info to the multi-feature si5351 VFO, and added details of a second si5351 VFO

28.2.16: The ZL2PD si5351a VFO, GPS frequency reference, Li-Ion battery monitor, CS2000 signal generator were added to the website

15.9.15: The OBD-2 speedometer and a digital QRP SWR meter were added to the website

18.6.15: Soldering stations, four dot clock and soldering iron cleaner added

17.3.15: In which Andrew described how Yahoo sent his email to another continent!!

30.10.14: Lots of new projects added


Welcome to my website. This site describes some equipment and circuits that I've designed and built. Many are related to amateur radio, but there are some test equipment projects, kit builds, and other things that I have built. I'd like to claim it's all been done to a plan, but that's not the case. It tends to be pretty random around here.  

In short, you can never tell what's going to appear here next!

And in that light, here's an update: I'm moving from the Middle East. Yes, after about six years living in the middle of the desert, I'm moving house (and ZL2PD workshop etc) back to civilisation. Not exactly sure where yet. That's a work in progress right now.

So, for the next few months, there will be little to no development around here. However, I will be publishing some designs (I hope) that I've completed just prior to the start of the packing/shifting/flying/unpacking thing.

Yes, it goes to show. You can never tell what's going to happen next around here.

What's (Not quite so) New?

The year has continued on with a cluster of new projects under construction and completed Some recent projects that I have completed include:

The Nighthawk 40m CW transceiver. This tiny 10W-capable transceiver is a SW-40+ clone kit available from China. It arrived after a mix-up with my order for an SSB kit. I built it anyway. But then nothing worked. Nothing.

Fortunately, I've managed to fix all of the (many) design errors in this kit. I'm really delighted to have it running. The whole story is here...

Next, here is a little aviation band receiver. I added a channel-based control board to a widely available aviation band receiver kit. (Are kits the theme on the website update this time around?) Then I packaged it in an unusually shaped 3D-printed enclosure to make it look more interesting. Even the knobs are 3D printed.

Inside the box, an ATtiny84 generates the DC tuning voltage for the varicap on each of 10 programmable channels using an unusually fast 16-bit DAC. The ATtiny also drives a small 7-segment LED display to show the channel number. A single button  select any of 10 programmable channels. All the details are here....

Continuing the kit theme, here's a review of a 5-digit crystal tester/counter kit which is available from a number of suppliers.

Because there is no accurate circuit information available from these suppliers, I've produced a complete schematic for it. And that revealed... Well, click here to read more... Of course, I had to design a 3D printed box for it. Details on the webpage.

This is so ugly, I almost didn't document it. Long before the ready availability of LC meter kits, I needed an LC meter a few months after arriving in my new  job in the Middle East. That's about six years ago. All I had were a few parts in a cardboard box. And the cardboard lid from the box. Can you see where this is heading?

Yes, in the absence of any prototyping board, or PCB, or just about anything, I ended up making an LC meter, and building it on a piece of cardboard. The design is based on Steve KD1JV's classic ELSIE meter with a few changes to the software to suit the parts I had available. Worked just fine.

But it's really ugly. If you can stomach it, there are some details here...

To balance off that ugly piece of work above, and completing the kit theme for this update, here's the result of some more work I did recently with my 3D printer. (Must change out that blue filament on the printer...)

I've designed a hexagonal-shaped case (which you can't really see from this photo!) for one of those cheap 8-digit counters from China. It looks nice on my bench, and it seems to work well, too. More details here...

Other Recent Designs:

A new si5351 dual output VFO/BFO with more features than I can list here. This has proven to be amazingly popular. Over 1,000 downloads of the software to date! It uses a Nokia 5110/3310 graphics LCD and it covers all of the usual amateur radio bands. Add more if you wish. The VFO's low power consumption (Just 30mA at 3.3V) makes it suitable for QRP, and it's cheap to build. The details are here...    

For those wanting a kit, there is one available from RV3YF. That's the kit pictured above. My prototype does not look anything like as nice. (Disclosure: I have NO connection with this supplier nor do I collect any royalties from sales) Since web links to these kits come and go, just Google "ebay si5351 dds vfo klopik" and you'll find it.

And thanks to Cristi YO3FLR, there's now a PCB layout available for this design, available from the Download section on the VFO webpage.

If one si5351 VFO/BFO design was not enough, here is another!! Yes, a second single band si5351 dual output VFO/BFO, this time with fewer than 20 parts. It uses an 8-pin ATtiny85 and an I2C alphanumeric LCD display. An S-meter/RF power meter display is built-in too.  Same low power consumption. And, yes, the Bascom source code software is all available as a free download. So now, you have a choice of si5351 VFOs on my website. The details are here...

Here are the details of an earlier design for a compact digital RF signal generator using a Cirrus Logic CS2000 chip. It's compact, with everything inside a small 3D-printed case. It generates a 3.3V squarewave output from 1.5 to 160MHz (although the specs on that chip claim it is limited to 75MHz) and draws less than 20mA from a 4 - 15V DC supply.

It's really the result of a tale of woe and misfortune, but the circuit works... More details here.

A speedometer for my new Mitsubishi Pajero. I know - It sounds silly. But when Mitsubishi designed the instrument cluster in the 2015 Pajero, they made it impossible to read in bright sunlight. Then they sold this car in the Middle East!! You gotta wonder....

Anyway, to stay alive on the roads here, I designed this little module. More details are here on this page.
Useful in other cars too. Works beautifully. Does daily duty on my office commute.

This is a compact digital SWR meter
for QRP (low power) transceivers and transmitters. It's compact, lightweight, powered by a single AAA battery. It uses a super-bright and easy to read OLED graphics display.

Did I mention it's small? And weighs just 50g ?

More designs coming up soon, I hope.

How to Navigate the ZL2PD Website

You'll find the complete list of these designs down the left hand side of this page. Simple 'click-on-em' buttons will lead you to each design. Schematics and other drawings are to be found all over the site, as are photos. Want to see the details close-up? Then just "right-click" on the image or schematic or whatever. Chances are, you'll now be able to see much more detail. And you can download it too, if you wish. 

To date, the details and designs here on my website include:

And there are some new designs, just added. See below...

A Magazine-like Website

This website is a little bit different to technical/amateur radio websites you might see elsewhere on the web. I think my website is more like an online magazine which has updates about every two or three months as new designs are completed.

That writing style is partly due to my desire to clearly explain how to duplicate a design. But is that what I should be doing? Or are shorter descriptions of my designs all that's required?

And if this website isdeveloping into something like an online magazine, I guess that makes this intro page a bit like a rolling editorial. Hmmm.

Elsewhere on the ZL2PD website ...

A suite of three different designs for temperature controlled soldering stations, with a detailed design for the most compact unit. It uses a single 8-pin ATtiny25 microcontroller and not much else, and it is packaged in a compact 3D-printed enclosure, also of my own design. (Right-click the image for a closer look or visit the web page)

For those looking for something a little different, here is a Four Dot Clock which uses just four cheap LEDs (Four dots of light, if you will) to display the time. It's surprisingly accurate. I only adjust it now about once every six months.

More interestingly, perhaps, is the fact that, unlike most clock designs you might have seen, this one does not require another chip to actually do the timekeeping. The clock's ATtiny45 does all that, and more.

And then there's this accessory for the temperature controlled soldering iron I mentioned earlier. It's a tip cleaner accessory using an easy to obtain item from the supermarket, and printed on a 3D printer.

Of course, all of the other designs are still available to browse and build, each listed over to the left in the index. Help yourself!

What else is on this website?

Aside from a page chattering on a bit about Yahoo and mail, my website describes a variety of projects related to my hobbies of amateur radio and electronics. These include circuit diagrams, descriptions of how they work and what they do, PCB layouts (sometimes), construction details, and software for designs which use microprocessors or microcontrollers.

For the record, the microprocessor designs here use the AVR chips including the ATtiny15, ATtiny25, ATtiny45 and ATtiny85, ATtiny2313, ATtiny26, ATmega8, as well as some earlier designs which use 8051 processors including the 80C552, 80C751, 80C51, 80C52, AT89C1051, AT89C2051, and AT89C4051, and so on. Almost all of my 8051 software is written in assembler while the AVR code is a mix of assembler and BASCOM (Basic).

Example image - aligned to the right

New Designs... Well...

There are some changes coming up around here which may delay some of my new designs for a while. Life happens, right? Looks like I've got a house move coming up which will mean the next update will be a few months away, maybe longer. Just when I thought things were going smoothly!  

So, the next stuff? Hard to predict, but maybe, possibly....

Another kit transceiver is under construction. When will I find the time to finish it?

A model train controller with sound effects (Not for me, it's for my grandsons, really!)

A couple of signal generators, with some unusual features (of course!)

DIY AA and AAA battery holders, and

A truly compact LC meter

And there are someother projects waiting in the pipeline. 

But really, it's all a bit of a mystery what will arrive here on my website next. Just depends.

Stay tuned... 

The Legal Stuff

You use the information published on these web pages at your own risk!

You may use the information provided here for personal or educational purposes but you may not reproduce it in any form or use this information for any commercial purpose without first obtaining written permission from the copyright holder.

There is no warranty or guarantee, either expressed or implied, covering any information of any kind which may be available from this website, or that designs and information provided on this website are free from patent or intellectual property rights of the author or third parties.

Should the information contained on this website be used by any party, that party shall by using the information provided be deemed to take complete responsibility for all risks and liabilities associated with its use and hold the author of this website harmless in the event of any claim, loss, liability or expense associated with any such use.

The rights of copyright over the contents of this website, unless otherwise noted, are claimed by Andrew Woodfield ZL2PD.

Example image - aligned to the right