Al and I will be attending Field Day and will be at the Milford Amateur Radio Club (MARC, W8MRC) at Paxton-Ramsey Park just outside the 275 loop, close to Wards Corner exit. We will be using Al's "Luggable Double-Double" Magnetic Loop antenna, shown here (he doesn't like that name...):
You'll notice this version has a vacuum variable capacitor (VVC) for tuning. Also note that Al 3-D printed the mounting brackets (in gray). He even has a thumbscrew clamp on the small driven loop! Tuning is done remotely using two encoders and a NEMA 17 stepper motor with controller. While not finished yet, it looks similar to this:
You can see the controller hardware in the background. Test thus far shows it has 13dB gain over a reference dipole. Naw...just kidding. Any ML antenna is a compromise, but for many HOA dwellers, it may be the difference between making and not making contacts.
Anyway, if you'd like to see it, come to the Park this weekend. We'd love to see you there!
jjpurdum