Matching antenna (CB7458E)

The coil and sockets of this circuit found in a QST depend on the frequency band that is intended to be tuned.

Touch Relay CK722 (CB23676E)
We found this circuit in Radio Electronics magazine from June 1960. The four-transistor circuit is...
Two-transistor regenerative receiver (CB20568E)
Details of the coil of this two-transistor generative receiver were not given. We found it in a...
Solar cell series connection (CB20479E)
In the figure we have the way to connect solar cells in series in order to increase their voltage. The...