Why are commercial loops so expensive?
Magnetic Loops require high voltage capacitors for more than QRP power level operation. These capacitors tend to be very expensive. A brand new Jennings vacuum variable can cost at least five hundred dollars (they are a lot cheaper used). High voltage stator and butterfly capacitors also cost a lot of money. So the final product including the capacitor can be quite expensive. Also, commercial manufacturers desire to build the best possible loop, so they employ all welded construction on loop joints. This also adds to the cost.
