Monday, January 22, 2018

Finally completed the "final" version of a working Light system

The other thing that has been keeping me busy outside of;
working on my 10GHz system, preparing for the Golf Channel AmTour's National championships, playing with my granddaughter and new grandson, and working to pay for all of this,
was fiddling with my light system, namely the housing for the receiver and transmitter.

This is what I came up with.
Front view

Transmitter, on the left, uses 12 SFH4550 IR Led's.  It also uses my 555 timer PWM modulator with an LM833 microphone amplifier.  I eliminated the filtering in the audio amplifier to simplify it as I found that it wasn't necessary.
The receiver is using a 90mm diameter fresnel lens with a 50mm focal point that I found on EBay, I've also seen them on Amazon.  These dimensions are almost perfect for the BPW34 IR detector.  The receiver is the KA7OEI v3.10 on a circuit board designed by K7RJ.
The housing for the transmitter and receiver are designed by me and are 3D printed.  More on that below.


View from behind
As transmitter uses 12 led's wired in 2 parallel sets of 6.  The box contains the circuit boards and the jacks on the back are, from left to right, microphone input, microphone gain, and power.  I've separated power for the mic amp (9V) from the pwm modulator (12V).  I am supplying 425mA to the led's driving them at a 20% duty cycle and I was afraid that I might get noise from the modulator into the amplifier.

First contact was made with Donn, WA2VOI a couple of weeks ago after Tuesday night coffee with the Northern Lights Radio Society at Nokomis Beach Coffee near Lake Nokomis in Minneapolis.
We worked out the narrow beamwidth and then made our contact.  After that we played around a bit bouncing our signals off of parked cars, houses, and piles of snow.  I logged the contact in Log Book of the World.  Just for information, it will take frequencies at lightwaves, I entered it as 3.52e+08 and LOTW resolved it.

3D Printing
I have uploaded my transmitter and receiver designs to Thingiverse.com.  I am making them free to anyone who wants them.
The Transmitter is at: http://www.thingiverse.com/thing:2751923
The Receiver is at: http://www.thingiverse.com/thing:2765972

Each of these prints used less than $1.50 in filament to print.
There are probably improvements that I could make to each of these.  If I develop any into a working example, I will post them here.  If you create any improvements please let me know.

10GHz woes...

It's been several months since my last post.  I have been busy!

Been working on my 10GHz set-up.  I am using a Khune Electronics 10GHz transverter with my Elecraft KX3 as the IF rig. 

After operating 2 contests with very little success I started digging into the transverter.
First I found that the receive gain was turned down, turning that up helped immensely.  The transmitter was a different story.  I was using the voltage monitor that is provided and no matter what I tried I couldn't get the output voltage to read higher than 2.9 mV.  According to the manual it should be 1.2 Volts.
I contacted Khune Electronics support and they were extremely response and helpful!  The engineer that responded to my initial questions provided me with my answers and additional test point to investigate to help her trouble shoot my problem.  After verifying the voltages at the test points the diagnosis was not what I was hoping for.  She asked me to return the unit for repair.  Sigh...

Their responsiveness to my questions has been outstanding so far, so I have no doubt that they will fix the issue and return it promptly.