My New Chinese Signal Generator

More amazing low-cost test gear from China.  Elisa gave me this device on the occasion of my completing another solar orbit.  Amazing capability for less than $90.  The video above gives you a good sense of what this thing can do.

I have already had success with the freq generator function.  The frequency counter also works great.  The sweep function looks very useful for filter checking.  And the ability to generate square waves at different phase relationships will be very useful in phasing receiver and transmitter projects.  

This little box should help me eliminate a lot of clutter on the work bench.  And it looks good next to the Rigol 'scope.  

Mine came from Amazon:

https://www.amazon.com/gp/product/B01A8S4TZK/ref=oh_aui_detailpage_o00_s02?ie=UTF8&psc=1

They come with a variety of different brand names:  I ordered a Jinwen but got a FeelTech.  They are obviously the same device.

Be sure to begin your Amazon shopping on the Amazon search link on the SolderSmoke blog (upper right).

QRP Wisdom from George Dobbs, G3RJV

This video makes me want to destroy my amplifier...

Alan Wolke Talks 'scopes on "The Workbench" Podcast

George KJ6VU is a long-time supporter of the SolderSmoke podcast.  He has recently teamed up with another ham and launched a podcast called "The Workbench."  This morning I listened to Part I of their interview with the legendary Alan Wolke W2AEW.   It was great.  As I was listening to Alan I was soldering together a crystal filter for my new receiver, and using my RIGOL 'scope to check the results.  

I liked Alan's description of how they made images of 'scope patterns in the days before the advent of Digital Storage Scopes (Polaroid!).  I also liked Alan's scorn for those who use the "Auto" switch on the 'scopes.  The host's reaction to Alan's description of a $300,000 Tektronix 'scope was also fun: "For that price I want to be able to drive a car into it and put a swing set behind it!"  Indeed.

Recommended listening:   
http://hamradio360.com/index.php/2016/08/30/ham-radio-workbench-5-oscilloscopes-part-1/

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).

 

73’s

Pete N6QW

ZL2BMI @ AA7EE -- Possibly the Most Beautiful DSB Rig Ever Built

Dave AA7EE has a very cool blog post on his version of the famed ZL2BMI DSB transceiver (seen above).  As usual, Dave puts most of us to shame with his excellent non-ugly construction and enviable in-focus macrophotography.

Check it out:
https://aa7ee.wordpress.com/2012/07/29/half-of-the-zl2bmi-dsb-transceiver-a-simple-80m-direct-conversion-receiver/

I especially liked Dave's discussion of how and why .1 uF caps are used in the coupling and bypass network between the two chips.

Of course, the only thing I don't like about this rig is the, well, the chips.  Can we persuade Dave to build the earlier discrete component version of this rig?

Be sure to read the many comments on Dave's post.   Our friend Rogier comments on the beauty of it all.  Edgardo LU1AR (the Argentine wizard with the gyrocopter) chimes in.  And we see  feedback from Eric Sears ZL2BMI himself.  FB. 

VIVA DSB!