Indoor loops

One of the great advantages of QRP is in the design of loop antennas for TX. With 100W, the voltage at the high impedance part of the loop can be very high, so that special capacitors are needed with low loss and a very high breakdown voltage. 

With QRP powers, ordinary capacitors may be used. Most times I use an old Wonder Wand Loop for 20m, 17m, 15m, 12m and 10m. My 10m loop, homemade with copper pipe, is sharper and more efficient, but harder to tune.

See https://sites.google.com/site/g3xbmqrp3/antennas/magloop.