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Friday, September 9, 2016

Oz JOO : An Australian Mighty Mite with 3D Printing

Hi Bill & Pete,

I have the JOO - joy of oscillation! The transistor is a 2N3053 with a clip on heat sink, but I don't think that I really need it. Output power +22dBm or 160mW. When I tested it on a Comms test set  at work, I found that the harmonics were about 12dB to 15dB down and I stopped looking at the 10th harmonic. Not good.

Fitting the 80m low pass filter (salvaged from another project) brought the harmonics more than 50dB down.

The coil former is a 31mm diameter and 3D printed by one of the guys at work. The material is PET - the material they make soft drink bottles from. After we printed it, I put it in a microwave oven with a glass of water. 30 seconds and the water got warm and the coil former stayed cool.

I haven't had a contact yet, but maybe in the next few weeks.

The next project is an 80m CW transmitter based upon the Goodfeller transmitter from QST 1946. It requires a inductor in the pi coupler, 1.5 inch diameter, 32 turns at 20 tip; but where to get one of those these days - wind your own.

I got the guy at work to also 3D print me a coil former with a spiral thread around the outside with a 20tpi pitch for the wire to lay in. Some hot glue and the coil is ready.

Now that I have finished all 189 episodes and two specials, my days are empty. Please make some more.

73 de Peter VK2EMU

Hi Peter (great name BTW),
Congratulations –really liked your build – top drawer! 3D printer access WOW – now if I could only get my 3rd son (Mechanical Engineer) to build me one of those machines.
The 3D made coil form is perfect for a VFO and follows the principles set down by Doug DeMaw W1FB (SK) about keeping the coil supported at both ends and away from metal. Bill needs a coil like that to mate with his HRO dial mechanism –and follows something old (dial) something new (coil).
Pete N6QW

1 comment:

  1. Ka Pai!(Maori - Google-trans it).
    Is there a Ham in the viewership here, in Bill's neck of the woods, who has the requisite 3D Printer he could lend? That would make 'something borrowed' ... Though not strictly part of the device, its contribution would be a boon.
    FB Peter, great callsign too!


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