From 
My son provoked me to lead a radio club in elementary school. Those of you who have tried to do something similar know what the current conditions are for ring activity. Nevertheless, I managed to get the ring going. We started in primitive conditions. The local school currently does not have workshops for technical education (the hygienist closed them due to high humidity). So, thanks to the understanding of the school principal, we were able to start in one class. 13 children came to the first meeting, pupils of the 6th and 7th grades, plus my daughter - a fourth-grader. Here we definitively agreed that we will meet every week on Wednesday at 17.00.
For the second meeting, the children should have brought 'breaking terminal blocks'. 15 of them have already arrived. In order not to discourage them and especially the parents in the current economic situation, we started by building a crystal with a single-transistor amplifier. I scavenged most of the parts from my 'veteshnik' stash. GC520 germanium transistors and 50 ohm telephone headphones. The children wound the coils, with varying degrees of success, on the paper tubes on which the microtene bags in the food were originally placed. The biggest problem was the rotary condenser. Where should I have gotten 15 at least approximately the same swivels. I remembered the old designs and tried a sliding capacitor from a matchbox. I was pleasantly surprised to find that it has a maximum capacitance of about 140pF and a minimum of around 40pF. Absolutely perfect parameters for such a primitive product. And mainly from available material. What did we use? One matchbox, a piece of aluminum foil, two about 10 cm pieces of wire from a telephone cable, and a wide transparent Chemafol adhesive tape as a dielectric. The success was huge. The children don't want to leave at half past seven and are curious about what we are going to do next.
Teraz ich zamestnávam trochu teóriou, ale iba v medziach ich chápania a znalostí, hlavne matematických. Samozrejme nebudeme sa iba venovať stavbe zariadení, na to by nám súčiastková základňa nestačila. Predvediem im rádioamatérske spojenia a naučia sa aj základy serióznej prevádzky na CB. Už ako by som počul niektoré voices: “ Na CB ich ideš učiť?!“ Áno na CB, ale tak aby, sa za spôsob prevádzky nemuseli hanbiť ani pred skúsenými OM. Predsa len CB je dostupnejšie ako klasická amatérska prevádzka . Veď za cenu jednej M160-ky dnes zoženiete jednoduchú CB stanicu. Na prevádzku na amatérskych bandoch musia deti čakať aspoň 3 roky (do 15 rokov) a na CB budú môcť začať už teraz. Uvažujem o tom, že ak sa podarí zohnať dosť CB staníc, začali by sme s prevádzkou miestnej siete a možno aj výcvikom morze cez CB. Aby sme nezostali iba pri prevádzke, plánujem postaviť s nimi postupne amplifier s LM386, spätnoväzobný audión a prípadne aj priamozmiešavajúci RX na 80 m.
By the way, does anyone have unnecessary rotary capacitors with a capacity of around 100 pF? Our 'boxes' are not suitable for short waves. I am attaching two pictures of the ring. On the first is the children's part and on the second is our crystal with box tuning.
Miro OM3CKU
om3cku@centrum.sk