160m ANTENNA PERFORMANCE AND EXPERIENCE

As stated on the previous page about 160m antennas, before we can define "Performance", we have to define the target.  What are we trying to work efficiently?  "DX" or "Local (NVIS)"?  "Both"?

HORIZONTAL ANTENNA PERFORMANCE is fairly easy to understand:
In General,  HEIGHT = MIGHT

A horizontal antenna (Dipole or Loop) is a good DX antenna when it is 1/2 Wavelength high.

However, this is ~80m (265 ft.) on 160m, ~40m (132 ft.) on 80m and ~20m (66 ft.) on 40m.

These heights for low band antennas are NOT abtainable for most hams.  Thus, many hams turn

to Vertical antennas if they are interested in working DX on the low bands.

For Local Rag Chewing and working NVIS, the best height is 1/4 Wavelength above ground.  Many people think even lower is better but that is wrong.  As the dipole gets closer to the ground than 1/4 w.l., its ground losses increase.

VERTICAL ANTENNA PERFORMANCE IS TRICKY!

It is often said that a vertical is a good DX performer, especially on the low bands. 

This is a PARTIAL TRUTH!

What many people don't realize is that the vertical radiator is only 1/2 of the antenna!

The other half of the antenna is the radial newtwork below the radiator!

Before we continue with Vertical Antenna Performance, it is important to understand the key factors that contribute to its performance:

Obviously, we want the Radiation Resistance to be as high as possible and the Ground and D.C. Resistance of the Radiator to be as low as possible.  This enables the highest efficiency from the antenna.

We decrease the Ground Resistance by optimizing the Radial Network.  "A Ground Stake in the Ground" is the worst possible Radial Network, being only slightly better than nothing at all!  As we add more radials, the Ground Resistance decreases and performance increases slowly, but with a diminishing return on investment. NOTE: a poor radial network can easily have 20 Ohms or more resistance. 

Thus, you can easily be losing half of your power in the ground, warming the rain worms!

We decrease D.C. Resistance in the Radiator by using a good conductor such as copper or aluminum.  A thicker wire has lower D.C. Resistance than a thinner wire, but there has to be a significant difference in size to make a significant difference in performance....because D.C. Resistance is very low compared to the other two types of Resistance.

Radiation Resistance is a bit tricky.  Radiation Resistance depends on the overall "physical length" of the radiator, not its "electrical length".  Whereas a full size halfwave dipole has a Radiation Resistance of about 73 Ohms, a full size quarter-wave vertical's Radiation Resistance is only half as much: 36.5 Ohms. However, since a 1/4 w.l. vertical on 160m is 40 meters high, there is not much chance of increasing its (physical) length to increase the Radiation Resistance!  Thus, we must use the most efficient way of electricly lengthening the radiator.  (Described Later)

IN SUMMARY: 

• We want to make the radiator as long as physically possible, and then use the most efficient way to load it electrically to resonance.  This will be described below.

• We want to use the best possible radial network to reduce Ground Losses as much as possible.

• We must use good conducting material in the Radiator.
  

RADIATION RESISTANCE OF SHORT VERTICALS

In his book, "hf antennas for all locations", Les Moxon, G6XN published a graph comparing "Capacitrive End-Loading" to "Inductive Center-Loading", showing the affect on the Radiation Resistance of short Dipoles.

I have modified his graph to show the affect on the Radiation Resistance of Short Verticals, by cutting the RR Ohm valuess in HALF. 

Notice "Capacitive End-Loading" is significantly better than "Inductive Center-Loading" except when the antenna is near Full Size.

Although Inductive Loading is easier to implement, it comes at a Big Hit to Performance!

PERFORMANCE: "BOTH"

So far we have seen how to use horizontal antennas for good NVIS (local) Performance and how to use good "short" vertical antennas with Top-Hat loading for good DX Performance. 

But what can we do when we seek good Performance for BOTH?

Good NVIS Performance requires high-angle radiation, but good DX Performance requires low angle radiation.  Simple Solution: Erect an antenna that has both!

The Inverted-L Antenna has strong low-angle radiation on its vertical segment and fairly good high-angle radiation on its horizontal (or diagonal) segment.

I have a lot of information on various INV-L Antennas on this web under the title of "Limited Space Antennas".  There you will also find lots of information on RADIALS.

HAM RADIO's BEST KEPT SECRET ABOUT VERTICALS AND INV-L ANTENNAS

The Importance of Radials

So how do thest antennas perform?  You will see...

In my opinion, the best place to test antennas in in BIG MAJOR DX Contests.

I began contesting in the U.S. in 1962, but only working 2 or 3 contests per year. Mainly Field Day and Sweepstakes contests, and only in CW.

The Army sent me to Germany in 1962 where I got seriously into contesting.

From 1972 until 2018 (46 years), I worked CQWW DX CW 45 times missing only one year.  I worked it from Austria (4U1VIC), Germany, Liechtenstein, and Luxembourg - about half the time as single operator, and several times as one of the operators of a Multi/Multi or Multi/Single station.  We set several country records and the ALL-TIME HIGH SCORE RECORD (for Europe) in CQWW DX CW and SSB contests.  I still hold one ALL-TIME HIGH-SCORE COUNTRY RECORD, Single Op, All Bands, High Power (Assisted).

During this time, I also worked CQWW DX SSB about a dozen times, Worked All Europe CW (WAE) about 20 times, FD (CW) most years and occasionally a few other contests.

  My biggest challenge was always 160m Long-Haul DX.

Prior to switching to an INV-L on 160m, in each contest I would struggle to work just one QSO with a stateside station on 160 to get the "multiplier". After that, I didn't even bother to call other stateside stations.

My first INV-L had a relatively short vertical segment (abt. 11m high), then ran horizontally to a distant tree.  My radial networked consisted of 2 elevated radials, 1 meter high.  One ran under the horizontal segment of the radiator, the other ran 180 degrees away from it.

The first time I called a stateside station, he replied. Then another and another. I called CQ. Several stateside stations answered my call. I worked them all. That was CQWW DX CW in 2006.

WHY HAD I WASTED 34 YEARS TRYING TO RUN 160m IN A DX CONTEST USING HORIZONTAL ANTENNAS?

         To be continued . . .   (Bed Time)