Roberts R881 Ferrite Rod

The Roberts R881 has this extremely high quality ferrite rod for the AM and SW band reception. If you have been building crystal radios, then you will realise that the ferrite coil is a critical component in the reception of radio signals.

Ferrite rods are available through online shops, and this radio uses the standard sizes. There are even sellers on eBay who sell ready assembled coils for your crystal radio projects.

Coil

Ideally, a coil should have zero resistance for a sharper Q value, which of course determines the sensitivity and adjacent channel rejection properties.

This Article Continues...