Broadcast - 16 March 2025
It’s amazing what drops into your YouTube “You might like” feed sometimes, this week there was a video that was titled “How to make a simple Morse Code transmitter for 80 Metres”, nothing unusual or surprising with that you might say….. However looking more closely at the picture of the populated printed circuit board and its construction method using diagonal hacksaw cuts to make solder islands, looked very familiar!
It was in-fact a project from a few years ago that Nic VK7WW designed and constructed to help celebrate 100 years or a century of amateur radio in Tasmania. An 80 Metre, crystal locked, QRP, CW 1 Watt transmitter project called the “Cent”.
The YouTube video was made by Jordan VK3ACU, who is situated in Victoria and covers his building of the project and its subsequent testing. Jordan presented a very clean compact version of the build and then put it through its paces. With his test set up it was easily heard using a remote SDR in Perth Western Australia, this would have been a distance of about 3000 Kilo Metres. He followed up showing a live CW contact approximately 700 Kilo Metres away in New South Wales.
This is only a short video, it is well produced and narrated and well worth the eight minutes to watch.
The link is included in the text version of this broadcast.
https://www.youtube.com/watch?v=6XIBcEhON3M
At morning tea last week it was good to see a couple of project updates of works in progress.
Firstly Trevor VK7TB, had his new Voltage Controlled Oscillator or VCO that he is designing and constructing. He had just finished machining a flywheel to attach to the drive shaft of a 1930s Bendix worm drive gearbox. The reduction gearbox provides very fine shaft rotation control on a variable capacitor. The precision machining of the flywheel was certainly obvious, with its smooth fit onto the gearbox drive shaft even without the grub screw being tightened. The overall tactile feedback was incredible, both from the point of just enough momentum from the fly wheel to the zero back lash in the gear assembly, all giving a very positive control effect. The feel was certainly reminiscent of “Top End” test instruments that I have been lucky enough to use over the years.
I think we might have to get Trevor in on a Club Technical Night for a bit more of an in-depth run down on this VCOs “from the ground up construction”.
The other work in progress came from Stuart VK7FEAT, who is collaborating with a friend to design and 3D print some “Radomes” or environmental shields to go over some omnidirectional antennas in the 1 Gig region. The first prototype looks great and hopefully it will fit their requirements otherwise we may see a few more variations.
I am sure we will get progress reports from both Trevor and Stuart.
As always pictures will be available on the NTARC Web site under “Blogs” for this broadcast. NTARC Blogs
UPCOMING EVENTS
TestNet and TechNet session - Every Wednesday, TestNet/CW course on 3.580MHz from 7 pm, then a TechNet on 3.567MHz from 7.30 pm till 8.30 pm. Your host for the evening is Nic VK7WW.
Club Room Technical night session - The next session will be on Wednesday the 19th March, at the usual time of 6.30 pm at the Club Room Archer Street, Rocherlea.
Coffee Morning - held every Friday in the NTARC Club rooms. Time is from 10 am to noon and we look forward to seeing you all there. So why not pop in check the QSL cards and join us for a cuppa, there is endless tea and coffee along with biscuits available for a donation.
Finally - A reminder to all members that if you have any items of news you would like added to our weekly roundup, no matter how trivial, then please email them to the Secretary at the following address news@ntarc.net all items to be received no later than 5 pm on the Friday prior to the Broadcast.
That’s all folks,
73, Stefan VK7ZSB, Secretary NTARC Inc.
