VK5TM


News, Updates and Other Minutiae

As a lot of people have pics of things unrelated to ham radio on their websites, I thought I would add a couple of my own (Scroll down for site updates). Banjo, our Red Heeler/Koolie cross at 4 months old. Banjo at 4 months And at 12 months old (Feb 2016) enjoying his birthday breakfast treat of banana on toast. Banjo at 4 months

May 2017

New project added - my version of the X-Phase noise canceller. PCB available and a kit of parts to follow soon

27 December 2016

Another addition to the Gallery section. This time, fitting a DDS module to a Philips PM5326 RF Generator to cure a bad drift problem.

26 November 2016

Additional software for the Simple DDS VFO added. This enables the pushbutton on the encoder to change step size (step sizes 10kHz, 1kHz and 10Hz). See the notes in the Download section of the Simple DDS VFO page for more info.

20 November 2016

I have had some interesting conversations with homebrewers over the last few years relating to experiments/modifications of the works published on this website. One of the things on the 'list of things to do', was to publish some of their pics' etc on my website, so along that line, the first one, a filter/leveller for DDS modules from G3OAG, is now on my site. This one and all the others I have available to show, will be posted under the 'Gallery' menu. Now that things are starting to return to somewhat normal around here, I will endeavour to get the others up as quickly as possible (with apologies to those that have been waiting to see their work in lights).

January 30 2015 update on the PSK kit project

Started on the test equipment to characterise the xtals for the filters. To make sure that I have an accurate frequency counter, I finally cased and made operational a 10MHz OCXO that has been sitting on the shelf for months. Not GPS locked (yet). OCXO construction OCXO construction OCXO construction Not sure how I'm going to label this one, it gets rather hot and sticky labels..... well, they don't, er, stick! Haven't measured the temperature of the case, lets just say, you don't hold it for very long. OCXO construction For the frequency counter, as I need 1Hz resolution, I used this design from the Burnham Beeches Radio Club. It is based on a design by EI9GQ. Rather than make a new pcb for it, I repurposed an old one that I built ages ago from a design in the last remaining Australian electronics magazine. Was never happy with it, so now it has a new life. OCXO construction Still need to put it in a case, but here it is reading it's own 10MHz oscillator source. The OCXO is bang on 10MHz according to the zero beat method of comparing it to WWV (after a 30 minute warm up). OCXO construction This is it's baby brother, same design, built a little while ago without the option of the OCXO frequency source. And yes, it also is waiting to be labelled. OCXO construction 4 February 2015. Just a quick pic of the OCXO frequency counter now boxed up. Labelling can wait until later. OCXO construction

January 28 2015 update on the PSK kit project

So much for the middle of January for the last of the parts, they arrived two days ago, nearly the end of January. No matter. I was in the workshop today, so here is a sequence of photo's showing the assembly of the receive section of the PSK kit. The reason there are no xtals in the filter yet, is that i still have to build the equipment necessary to characterise the 200 odd xtals I ordered for this. How it is shown here is very similar (minus any tweaks), to how the instructions will be for building the final kit. The receive section and oscillators will be first. Then this part will be setup and made operational before building the transmitter section. 1st stage PSK receiver construction 2nd stage PSK receiver construction 3rd stage PSK receiver construction 4th stage PSK receiver construction 5th stage PSK receiver construction 6th stage PSK receiver construction 7th stage PSK receiver construction 8th stage PSK receiver construction The transformers used to isolate the input and output audio paths have a "P" on one side to signify the primary. This is the side that will be interfaced to your computer/laptop that you are using. input/output transformer marking

January 2015 update on the PSK kit project

90% of the parts for prototyping the re-vamped PSK20 kits have arrived and the rest should be here by the middle of January. Originally, I was hoping that the kits would be available early this year, but some parts, notably the PA transistors are on a 12 week lead time, which I can do nothing about, so the release will be somewhat delayed. As things progress, I will post the news here and on several Yahoo groups that I will list closer to release time.

A quick update on happenings - Dec 2014

As a few know, I am working on re-engineering Dave Benson's PSK series of kits, getting them ready for re-release. The first batch of prototype pcb's arrived yesterday and I've already found two mistakes. Just as well I know where to get them made real cheap! First mistake is not removing a via after re-routing a track (luckily, that one is not going to cause a major problem) and the second was not putting the right size holes for the cans of the transformers in the output bandpass filter. I dare say I will find something else. Another problem related to this time of year (Dec 2014), is the slow down of the delivery services due to large demand and components being on back order and taking a while to turn up. Here is a pic of the first prototype pcb. First PSK prototype pcb And before you ask "Where is the PA stage?", that is the next stage once this part has been sorted. Also, to get the pcb's within the 100mm x 100mm prototype pcb limit of my manufacturer, I have made all off board connections via flying leads instead of having them pcb mounted. Still waiting for parts to build and debug the first prototype, so it looks like my initial timeline of having these ready early in the New Year will be pushed back somewhat. There are some other changes I have in mind, one of which is the use of the Si5351 oscillator chip to replace the two oscillator crystals. The aim being to make these more frequency agile.