12-09-2018, 07:29 PM
Bo
I still have rats-nest 16.000 test oscillator and I used it earlier this year when I did some 2M and 70CM yagi antenna pattern checks.
I also looked through all of the TTL oscillators in the junkbox quite a few years ago (>10), grabbed the best frequency assortment and mounted them onto a piece of Veroboard. The board was then mounted in a 'pre-loved' diecast box with a 10 position rotary switch that simply switched the +5V from the single regulator to the individual oscillators. Their outputs were commoned by individual 22pF capacitors to a single point and then to a BNC socket.
I wrote the frequencies on the box at the knob pointer but I had some useful frequencies that made the project worthwhile and they included 6, 8, 10, 12, 15, 16, 24, 36 and 50 MHz. Add the harmonic content and there are test signal frequencies all over the place. The 10th position was power off.
Like your project, the internal 9V battery works well with it and has a long battery life.
The moral is 'don't just chuck out old computer motherboards, I/O and video cards without removing the TTL oscillators'.
The newer style mostly-SMD boards are not as good a source of them...
Doug
I still have rats-nest 16.000 test oscillator and I used it earlier this year when I did some 2M and 70CM yagi antenna pattern checks.
I also looked through all of the TTL oscillators in the junkbox quite a few years ago (>10), grabbed the best frequency assortment and mounted them onto a piece of Veroboard. The board was then mounted in a 'pre-loved' diecast box with a 10 position rotary switch that simply switched the +5V from the single regulator to the individual oscillators. Their outputs were commoned by individual 22pF capacitors to a single point and then to a BNC socket.
I wrote the frequencies on the box at the knob pointer but I had some useful frequencies that made the project worthwhile and they included 6, 8, 10, 12, 15, 16, 24, 36 and 50 MHz. Add the harmonic content and there are test signal frequencies all over the place. The 10th position was power off.
Like your project, the internal 9V battery works well with it and has a long battery life.
The moral is 'don't just chuck out old computer motherboards, I/O and video cards without removing the TTL oscillators'.
The newer style mostly-SMD boards are not as good a source of them...
Doug
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.