Capco SP-300 ATU USED | 90 Days Warranty

Capco SPC-300 Manual Antenna Tuner, Made by Cap Co electronic run by the late Tony Jonson G4OGP. Famous for his popularisation of magnetic loops, they also used similar capacitors made by his company in their design.

This allows the user to admire the beautiful wide-spaced capacitors and the roller coaster inductor whilst in use.

Tony used to brag he could tune up the bedsprings of a mattress with it, and indeed the SPC design does indeed offer a large impedance tuning range. With this unit on his stand, I think he also tuned up a coat hanger on 14 MHz to the delight of passers-by.

Both capacitors have drive speed reduction and the inductor has a turns counter. There are 2 unbalanced outputs and 1 balanced output from a toroidal balun. This output was connected to 800 ohms (often homemade) twin feeder to the centre of a Windom antenna.SWR then scarcely matters on such a high impedance line as losses at low HF will be negligible. Outperforming long runs of coax when tuning up such mismatched antennas.