Ham radio contests are a great opportunity to check your station’s performance, especially comparing antennas and their relative performance.
One of our most popular contests is CQ Worldwide CW on the last weekend of November each year. It’s a truly global contest, with hams from most countries trying to make as many contacts as possible. This year, we found relatively good conditions for much of the weekend, including many signals on the higher bands like 15 meters.
With my new ANAN-7000 DLE MKII, I can run two identical receivers coherently. Each has a different antenna. Above, you can see a snapshot of CW activity centered on 21.040 MHz. On Channel 1, I used the beam atop a fifty foot tower. On Channel 2, you will find my wideband magnetic loop antenna at six feet above ground.
Surprise! At a quick glance, you can’t see a whole lot of difference. My AAA-1C active loop performs almost as well as a “real” antenna. This really is surprising, as loop performance tends to drop off at higher frequencies.
Now, there are three differences. First, beam antennas a more directive, especially with forward and front-to-back gain. Loops tend to be more omnidirectional, except for their broadside null. Second, signals are stronger on the beam, by a typical 10-12 dBm or about two S units. Third, a beam at height is better for more distant (low angle) propagation, while the loop is more favorable for mid-range or higher-angle signal paths.
But, overall, comparing antennas with identical receivers shows that you can get great performance from a wideband loop.
Comparing Antennas Across the Bands
I have decent resonant ham antennas for 7 to 30 MHz, so I can only compare on those frequencies. On 40 meters, loop signals are much weaker, but noise is even more reduced. Hopefully, with better propagation during Cycle 25, I will be able to do some contest comparing antennas next year. I have done some comparisons on 12 meters this fall, and the loop holds up really well at 24 MHz.
Some of the digital modes, like FT8 and WSPR provide signal strength and signal-to-noise measurements. If I can figure out how to run a two copies of a digital decoding program at one time (one for each channel) some further antennas comparisons might provide interesting results.