I do not have great experience in high frequency PCB design, thus, i made some design mistakes on the PCB, but i discovered it later on, during the test runs. This is the first PCB design for the circuit:

A slight modification: As i plan to install this project on my workbench, near the main power supply, i have removed the 7805 and 7905 chips. Instead, i get directly the +- 5 volts from my power supply. As for the IC2, you may notice that is missing from the schematic diagram. The PCB was created with the IC2 (TL72P) to control the frequency select and fine tuning. But during the tests, i got bad results, and therefore i replaced it with two 10K resistors. The schematic diagram that follows, corresponds 100% to the PCB that i published above, yet i discourage you to use it for your own projects. Unfortunately, i have not yet design a PCB that has this change corrected.

I used my brand new etching bath for etching!	The PCB right after the etching	Backlit

I tried to have the grounding layer all around every wiring. Also, there is no bridge for the grounding layer, not that this is important. It is all in one piece. Yet, i do have 4 bridges for other positions of the PCB. The fact that i designed this circuit on a single side board was probably a mistake. I will get some more knowledge for high frequency PCB design and re-design this PCB, maybe on a double-side PCB.

The soldering of the parts had to be done very carefully, as the grounding layer had just .1'' insulation. I used the smallest tip i had for my Antex. Here is the PCB with the parts soldered:

The range selector is a 12-position single pole rotary switch. Each switch position corresponds to a different capacitor. So, either i would solder the capacitors to the PCB and draw 12 (+1 for common) wires to the selector, or i would do this:

First, i made a ring with a thick single core wire (2.5 mm²). The diameter was about 10mm larger than the diameter of the rotary switch. I cut and soldered the two edges of this wire to make a closed ring. Then, i soldered one terminal of a capacitor to one position of the rotary switch. The other terminal of the capacitor was free, outside the switch's diameter. On this terminal, i soldered the ring. Then, on the symmetrical pin of the switch, i soldered likewise another capacitor. I did this for all 12 capacitors. When i finished, i had all 12 capacitors connected directly on the selector switch, and only 2 wires would now be required to departure from the PCB, the 0V wire which is connected on the ring, and the COSC input for the chip.

I made a ring with a single core thick wire, with diameter roughly 10mm bigger than the switch's diameter.	I cut and soldered the wire to make a closed ring	I soldered one terminal of a capacitor to one terminal of the switch

On the other side of this capacitor i soldered the ring	I did this for the symmetrical capacitor	And finally for all 12 capacitors

Name   Email (shall not be published)   Website Notify me of new posts via email Write your comments below: BEFORE you post a comment:You are welcome to comment for corrections and suggestions on this page. But if you have questions please use the forum instead to post it. Thank you.