Tape measure to wind up transformed into a portable ham antenna
If there’s one thing radio amateurs are good at, it’s turning just about anything into an antenna. And the hams also have a long history of portable operations, where they drag a (sometimes) minimalist setup of gear into the woods and set up shop to pack contacts. Bringing the two together, as with this field-portable antenna made from a tape measure, is a double win in any ham’s book.
For [Paul (OM0ET)], this build seems motivated mainly by the portability aspect, and less by the “will it antenna?” challenge. In accordance with this, he chose a 50-meter steel tape measure as the basis for the construction. Mind you, this isn’t one of those retractable tape measures, just a long flexible strip of metal on a roll-up spool in a plastic case. His idea was to use the band as a radiator for an end-fed half-wave antenna, or EFHW, a multi-band design that is a popular option for radio amateurs operating from the 80 m band to the 10 m band. EFHW antennas require an impedance matching transformer, including a miniature version [Paul] built and stored in the tape measure case, with a BNC connector to connect to the radio and a flying lead to connect to the tape.
Since a half-wave antenna is half the target wavelength, [Paul] cut the last ten yards of the ribbon to save some weight. He also scraped the coating of the tape about 40 yards away, to make good contact with the alligator clip on the fly leash. The first video below details the construction, while the second video shows the antenna being tested in the field, where it met all initial criteria for portability and ease of deployment.