Alpha Antenna Alpha Loop
$$$$·
| Frequency | 80m: 3.5-4.0 MHz, 60m: 5.3 MHz, 40m: 7.0-7.3 MHz, 30m: 10.1-10.15 MHz, 20m: 14.0-14.35 MHz, 17m: 18.068-18.168 MHz, 15m: 21.0-21.45 MHz, 12m: 24.89-24.99 MHz, 10m: 28.0-29.7 MHz |
| Bands | 80m, 60m, 40m, 30m, 20m, 17m, 15m, 12m, 10m |
| Modes | SSB, CW, AM, FM, digital |
| Connector | SO-239 |
| Year | 2015 |
| feedpoint | SO-239 |
Estimated (unverified): weight (~2.5 kg) and per-band gain (magnetic-loop efficiency varies strongly by band)
A commercial magnetic loop made for portable and restricted-space use. Manual 6:1 reduction-drive tuning, with a base model available with a wired remote tuner. Covers 10-40 m at 100 W PEP SSB (50 W CW, 25 W digital), and 60/80 m at 20 W with the Booster Cable. The 3 ft loop sets up quickly on a tripod for POTA, SOTA, or apartment operation.
Costs more than a comparable homebrew loop. Magnetic loops are inherently inefficient on the lower bands. The bandwidth is narrow, so it needs frequent retuning. Power handling is modest and drops on digital modes and on 60/80 m. The tuning capacitor carries high voltage on transmit, an RF and burn hazard. The tuning null is sharp on the higher bands.
A commercial magnetic loop for operators who would rather buy than build. A well-built homebrew loop can rival it for much less money, but the Alpha Loop comes assembled with a smooth reduction-drive tuner. A base model with a remote tuner suits permanent installs.
A magnetic loop is the antenna for people who are not supposed to have one, the apartment dweller, the HOA prisoner, the operator working from a hotel balcony. Instead of a quarter-wave of wire in the clear, it radiates from a small tuned loop, and the Alpha Loop packages that idea into a roughly 3-foot (0.9 m) ring you can stand on a tripod in a minute.
The trade is bandwidth for size. A loop this small has an extraordinarily high Q, which is the polite way of saying its tuning is razor-sharp: you retune the capacitor every few kilohertz, and the 6:1 reduction drive exists precisely because a coarse knob would be unusable. It covers 10 through 40 m at 100 W SSB (50 W CW, 25 W digital); add the booster cable to form a larger double loop and it reaches 60 and 80 m, but only at about 20 W. Magnetic loops are inherently lossy on the low bands, so those figures are honest physics rather than a defect.
One safety point is easy to overlook: on transmit, the tuning capacitor sits at a very high RF voltage; do not touch the loop while you are keyed up, because it will bite. The original portable model feeds through an SO-239 box; the EmComm variant ships with a BNC connector and feedline instead. A well-built homebrew loop can match it electrically for a fraction of the price, but few homebrews arrive assembled with a tuner this smooth. For portable wire alternatives that solve the same restricted-space problem from other angles, see the Buddipole Mini and a resonant end-fed half-wave.