Author Archives: admin

Surface Mount Soldering – Tools

This set of tools is (in my opinion) some great tools for SMT soldering without going the reflow route (which requires an oven).This shopping list costs approx. £180+VAT and is complete. Tools required A temperature controlled soldering iron (approx 50W), … Continue reading

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Long-tailed-pair oscillator

I needed a quick alarm tone generator for a piezo speaker, and with no 555 at hand, this turned out to work quite well, and it’s just as small. It operates with just a few mA current. It is a … Continue reading

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EAGLE CAD Toroid drawing tool

This small bit of software can auto-generate a toroid outline for EAGLE. You can select horizontal or vertical mounting, and specify the toroid dimensions and the number of wire turns. It will generate an EAGLE script file (.scr) that can … Continue reading

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EAGLE CAD layers reference

This document eagle-cad-layers-reference3.pdf explains what all the layers in EAGLE mean when it comes to PCB component and board design and how the PCB manufacturer will interpret it, with real examples. The EAGLE documentation is awful for this. Personally I … Continue reading

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EAGLE CAD SMD tool

After getting fed up manually creating device packages for EAGLE, the following tool was created. It allows for the automatic creation of many SMD packages. Here are some examples:       The tool just needs some values entered, which can … Continue reading

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Toroid (Amidon) calculations

The excellent website changpuak.ch here and  here  allows you to figure out what core and number of turns for a given inductance, for ferrite and iron powder toroids respectively, and also to see the impact of adding or removing turns. … Continue reading

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Quadrature detector coil

Here are photos of the elusive 235SU1 coils. One will be disassembled in the name of science! It can be seen that the primary coil has the tuning slug pulled out a bit. This kind-of agrees with parts of the … Continue reading

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Tuned Front End for FM receiver

The Ryder paper (here) uses a tuned front end. The specified coils (Toko E526HN-100319) seem to be unobtainable, but surprisingly, E526HN-100119 are available (just about), and it looks like they are very similar (I don’t know what the difference is). … Continue reading

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Modern take on Ryder’s FM Receiver

The link here shows an FM receiver with a high level of claimed performance. The diagram here shows a snippet from the paper. The problem is, most parts are obsolete. It is an opportunity to try to improve areas of … Continue reading

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Another Test Probe

This one used an SMA plug, so it is a bit more versatile. The SMA plug was from Maplin. The 1.02mm tips from Pomona fitted quite nicely into the center pin of the SMA plug as shown here, and it … Continue reading

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