To the ham friend who recently complained at lunch sitting beside me over a plate of breakfast, that I am writing too much and it takes too long to read, I apologize in advance for yet another blog post. 🙂 Apparently I’m doing a good job of keeping you pinned in your seat, though!
Electromagnetic energy, as I have remarked before is a weird, spooky little beast. It has a desire to return home greater than any bug eyed extra-terrestrial. I mention this after another day of antenna radial wrangling, following some reading about radials and how they affect antenna directionality.
The point of adding radials to a vertical antenna, like a hamstick is to balance the circuit so that electricity can crawl back home more easily. If you were using a dipole, the two halves of the dipole do this fairly efficiently, but a 1/4 wave vertical is by it’s nature unbalanced and needs an assist.
Usually, if you’re setting up your vertical antenna in the back yard, you’d spread radials out as evenly as possible along the ground or just minimally buried, and have 8, 16, 32 or more radials.
These radials couple capacitively with the ground giving the electricity an easy path back to the antenna to complete it’s circuit.
The closer the radials are together, the less of a jump there is for the electricity to hop on the easy train back, and the more evenly the current circulates. And also, the more evenly the antenna radiates in all directions.
But when you’re an apartment dweller, with a tiny little floor space, room for radials is nearly as problematic as getting your rig grounded! So you end up with a pretty big compromise.
Radial Voodoo
In my 3rd floor apartment shack, I have a very minimal radial setup consisting of only ONE radial wire which I use for 20m and 30m, and ANOTHER longer wire for 40m. I have these taped to the apartment’s wall with blue painters tape, running north from the window to the room’s corner.
The 40m radial also turns the corner and runs a few more feet to the west, where I have it rolled up and slid onto a shelf when not in use. When in use, I unroll it across the bed to get a better signal out!
You wouldn’t think it would make that much difference, but a look at my 40m propagation reports with the radial rolled out and without it rolled out that last few feet across the bed has me convinced otherwise.
In any case, it’s a pretty unbalanced setup, and it’s surprising that I get the signals out as far as they do go.
Dipole Antenna Directionality… Hmmm..
In earlier reading regarding dipole antennas in different configurations– standard horizontal, vs. V and inverted V, and L-configurations, (which I arrived at after buying a Wolf River Otophone), I learned that an L-configuration Dipole (one leg vertical, one leg horizontal) creates an antenna that is directional in the direction of the horizonal leg, instead of broadside to the horizontal leg.
This got me wondering if the same applied to a single radial– did the single horizontal radial with a 1/4w vertical, which on paper looks an awful lot like a L-dipole, create propagation more in one direction than in others?
Looking around my room, there was one more place I could put a radial in another direction, mostly perpendicular to the north-south radial, and that was east-west along the back of the pony wall of the loft staircase.
I was a little leery of this location however, because it runs right behind the TV, and I suspected there would be more RFI issues introduced if I put a radial there.
Plus, it’s only viable on 20-30m because the wall is too short for a 40m radial.
The Results of the Perpendicular Radial
After thinking about this for a while I got out my roll of wire and cut a ~16ft piece, attached a power pole connector to the end, plugged it into the connector on the antenna bracket, and taped it to the back of the pony wall.
In the early afternoon I fired up the Icom-7300 on 20m and started transmitting.
I had been transmitting just an hour or two earlier and was seeing a familiar pattern in the morning with the single radial installation.
Usually on 20m, (when there isn’t a huge anomaly disrupting the band like last week) I see a pattern of signal propagation that includes most of the West Coast, Texas, intermittent Idaho, Utah, Colorado, New Mexico, lots of Texas, some of the eastern states, a few drops of Canada and Mexico, Cuba and Puerto Rico, with a smattering of Australia.
I see very little of the top of the country in the Midwest–Wyoming Montana, and the Dakotas are just random luck to catch.
But with the second radial installed, what I immediately saw on PSK Reporter was a beautiful dense upward fan pattern from coast to coast.
I lost some of my reach into Mexico, and towards South America– but gained most of the eastern states all the way to Maine, and a huge swath of Canada, including Prince Edward Island, which I had never ever seen a signal into, or out of. And then there were easy, and multiple contacts into former black holes of Montana and Wyoming.
I also saw a LOT of signals bouncing over to Europe, and picked up a lot more incoming signals from DX sources than normal.
So over all, from one day’s testing (I spent about 7 hours working 20m today) I would say the second radial resulted in a much different, and mostly better radiation/receiving pattern that was denser and more plentiful than with only one radial.
But Then There Were the Television Poltergeists…
Remember my concern about the second radial running right behind the TV along the pony wall?
As soon as I started transmitting, RFI reared it’s roaring head like a malevolent ghost in the machine.
The TV turned off. Then On. Then Off. Then On. Stopped responding to the remote, and eventually I had to unplug it to even get it to stay off.
I’m sure this is because of the way many electronics are never quite off to enable them to start and boot quickly. Obviously, I’m going to have to go on another ferrite installing spree that includes the TV if I hope to keep using the second radial.
The kicker was when I finally quit working the radio, and plugged the TV back in, it came back on with the volume turned all the way up to 100!
Electrical Poltergeist syndrome was alive and well! Yikes! But at least the remote is now working.
There may be days I want the old antenna radiation pattern back. Sometimes it’s nice to hit Brazil, Columbia, Puerto Rico, and Mexico!
Fortunately, with the Anderson Power Pole connectors attached, I can just unplug the second radial– or the first, if I want to try a different configuration.
Weird Incoming Storm Shape on Radar
One last weird thing.. when deciding on whether to bring the antennas in for the night because I could hear the windows rattling, I saw THIS developing on radar over my area.
I brought the antennas in. Nuff said.