Take the time to compare your HF receiving antennas in action. I did, and the results are very interesting.
I am constantly amazed by the performance of my ground mounted wideband loops. These perform well, even when compared to full sized ham radio antennas on a tower.
My ham radio setup is modest but useful. Above, you can see my HF beam on a fifty foot tower, with a 40 meter dipole just below. My beam is a Force 12 C3SS, comprised of two-element beams for 20-15-10 interlaced. It works well on the WARC bands too, as well as six meters (with a tuner). With my added advantage of being on a hill next to a park, it performs nicely.
In recent years, I have added some near-ground mounted LZ1AQ wideband loop antennas, which I use individually or in a 100 foot array. My station is set up to switch between my HF receiving antennas, making comparisons easy.
Most of my shortwave broadcast listening occurs in the 31 to 19 meter bands (9 to 16 MHz). Most of the time, the tiny magnetic loops perform almost as well as the beam on the tower. By “almost as well”, I mean within 6-10 dB difference, or 1 to 2 S-units. In the 20 meter ham band, the beam is consistently better.
By the way, since antennas a reciprocal, this means that a small transmitting loop at near ground level would give similar performance for making contacts.
HF Receiving Antennas Compared – Not Always Equal
But sometimes, the beam is much better on the SWBC bands, by 20 dB or more. And, occasionally, the loop is much better. So, what gives?
Is the difference due to radiation patterns? A beam on a tower has a directional pattern and is better for lower-angle signals. By comparison, at HF, my loops are pretty much omni-directional. Is the difference due to polarization? My loop is oriented vertically, while the beam is horizontal.
The answers are surprising. In the next few articles, I am going to run these antennas through antenna modeling software and provide you with the results.
Looking forward to the results of your comparisons. 73 Greg W2BEE
John, one of the joys of radio is experimenting with various antennas. We always are looking for something just a little bit better. Of course, no one antenna is the be all. Enjoy the process, and I look forward to reading more in the future!
Antennas are not always reciprocal. When transmitting, you have to consider output power, antenna efficiency, non-reciprocal paths, and nearby metal objects. For example, I often hear Indonesia in the mornings booming in on 40m, on an inverted vee (FT8). But even with 400W on the same antenna, they almost never hear me – also verified by PSKREPORTER. I could give many other non-reciprocal examples too.
Thanks, Jerry. I think the proper way to look at this is that while the antenna itself is reciprocal, many other factors in the circuit (e.g. propagation through the ionosphere) are typically not. That’s probably worth an article in itself.