Step 7: The Wiring for the Antenna. Use your pattern to mark that spot on your two main winged pieces. Then, use a drill to make two holes through those spots. Then the screws will need to be put through those holes. Then, take out your transformer which has the coax plug on one side and twin lead on the other. How To Get The Best Reception With Your HDTV Antenna By Matthew Braga on Aug. 24, 2010 at 8:01 a.m. Getting a true HDTV signal isn't as simple as throwing up some wire and hoping to catch whatever's near — it takes some smart placement and a few simple tweaks.
Doug Adams must have not been an amateur radio operator for he seems to have missed the answer to everything suggesting 42 as the answer to it all.
Perhaps he is right for many things, but for ham radio folks evaluating antenna choices a popular answer for the height of a vertical antenna for the HF bands appears to be 43.
Be sure to check out the many posts about the 43 foot antenna here on this web site.
If you have been in the market for a vertical you have probably noticed the availability of a “tuner required” vertical which is forty-three feet in height above a reasonable ground plane of radials. Indeed Zero-Five, DX Engineering and others offer this exact configuration in their model lineup claiming “all band” operation from 160 to 10 meters. Can this really be true?
This is also known as a 13 meter vertical. Here is a discussion of why this compromise length exists with some pitfalls.
Forgoing the need for a tuner (which is arguably not too big a deal) let’s have a look at the predicted patterns using NEC. To set up the simulation, I copied a vertical antenna with four radials from the Cebik model set available for purchase on his web site. The only thing I changed was the antenna height and the radial length.
I chose Cebik’s vertical example to ensure I leverage his knowledge of how to model radials reasonably well in NEC which, in my case, uses NEC2 as the engine. NEC2 does not model underground radials so Cebik’s technique is a welcome insertion of NEC2 trickery. Plus, I wanted to capture all the appropriate assumptions he makes for vertical over radials NEC antenna simulations.
The antenna looks like this…
Now here is the predicted patterns using a typical frequency of the main HF bands. Note the “Primary” trace is the one plotted for the 10 meter band…
The peak radiation angles and relative antenna gain for each bands are:
Several things are apparent:
You can see why the ten meter case has the high angle radiation when you look at the currents along the vertical as shown here…
The opposing current phases destructively interfere at some angles and constructively interfere at others.
Is this an all HF band antenna? Well, because it operates at no particular “tuned” length for any HF band, except maybe 60 meters, you will always need a tuner. So, sure, it can tune up anywhere the tuner (or matcher if you prefer) can match. If you have to have just one antenna for HF, maybe this is a good choice, especially during the current great low band conditions in this low sunspot point in time.
A better reason to consider this antenna is for reasonable 80-20 meter use and as a practical thing to try for the 160 meter band. Because you can tune almost anything to almost any band, it is possible to get 10 and 15 meter use too with the propagation issues described above.
Other advantages for this 43 foot antenna is expense. You can have one for a few hundred dollars and several major antenna manufacturers, noted above, make them. The variables between the manufacturers is likely strength in materials and other mechanical design issues. Look to Eham for evaluations.
In my quest for a do it all vertical to replace my 16.6 foot copper pipe my choices include:
Because I am getting good results on 20 meters with my 16.6 foot vertical, I am not interested in dipole solution #5… yet. Thus, I desire to bring some closure to this vertical installation and make it the best it can be.
I am still leaning towards the SteppIR BigIR Vertical even though it is a bit expensive. Being able to tune the antenna precisely to the appropriate length is a great feature reducing standing waves on the coax.
However, the simplicity of solution #3 means no additional wires to the antenna to power an automatic remote tuner or drive the SteppIR motor. This is just radio (with built-in matcher), coax, antenna. I lose some power in my very long coax with the standing waves, but have a much more reliable system. Uncomplicated solutions are certainly well worth considering.
No matter what your choice, if you want a vertical, consider the investment you will need for the radial system. Get the DX Engineering Radial plate and just do it. It really helps.
One more point is worth mentioning. The various makers of 43 foot vertical antennas all suggest the use of a 1:4 balun. Some suggest using a balun model made specifically for “tuner use” with the idea these specialized units have the robustness needed to handle the less that ideal voltages and currents. A nice balun costs good coin and is certainly worth it. Just be sure to roll this expense into your trade study when comparing this 43 foot solution with something like the BigIR vertical.
Also watch out for aluminum components near the ground. Certain soil conditions will dissolve aluminum.
DX Engineering and Zero Five Antennas seem to be in hot competition in the vertical market and they both have an approximate 43 foot system to sell you. If you are in the market for this kind of vertical start your trade study with these two manufacturers.
Good luck.
G1B01 from the General License Course Section 1.3, DX and Details:
What is the maximum height above ground to which an antenna structure may be erected without requiring notification to the FAA and registration with the FCC, provided it is not at or near a public use airport?
A. 50 feet
B. 100 feet
C. 200 feet
D. 300 feet
Flying into a radio tower unexpectedly usually makes for a bad day for a pilot and passengers. Amateur radio antennas must not be a hazard to aircraft, so the FCC and the Federal Aviation Administration (FAA) limit the height of an antenna structure to a maximum value. Towers may exceed this maximum value only with formal notification to the FAA and registration with the FCC. With the notification and registration the tower information can be placed on aviation navigational charts and minimum safe altitude values for aircraft may be adjusted accordingly. It is a win-win for the pilots and the antenna owner.
We will come to the specific maximum allowable height in a moment. First, let’s consider a special case to which this question alludes that is detailed not in FCC Part 97 where the Amateur Radio Service rules and regulations reside, but rather in the FAA Code of Federal Regulations, Title 14, Part 77.9(b). You’ve read that one, right?
In distilled form, this FAA regulation says that if your radio station is within 20,000 feet (3.79 miles) of a public use or military airport you must not erect an antenna structure higher than a calculated value that is based upon the distance of the antenna from the runway. This makes some sense generally – if you are really close to a runway you want to keep the antenna quite low. If you’re a couple of miles away from the runway a bit higher antenna is probably OK, but how high can you safely and legally go? The height limit is defined as a sloped imaginary surface up from the runway. (With shorter runways the distance for consideration is 10,000 feet, as noted below.)
Here’s what the FAA part actually states, keeping in mind an antenna tower is “a construction or alteration:”
Any construction or alteration that exceeds an imaginary surface extending outward and upward at any of the following slopes:
(1) 100 to 1 for a horizontal distance of 20,000 ft. from the nearest point of the nearest runway of each airport described in paragraph (d) of this section with its longest runway more than 3,200 ft. in actual length, excluding heliports.
(2) 50 to 1 for a horizontal distance of 10,000 ft. from the nearest point of the nearest runway of each airport described in paragraph (d) of this section with its longest runway no more than 3,200 ft. in actual length, excluding heliports.
(3) 25 to 1 for a horizontal distance of 5,000 ft. from the nearest point of the nearest landing and takeoff area of each heliport described in paragraph (d) of this section.
The graphic below illustrates an example of a station one mile from a longer runway (>3200 feet) and a station one mile from a shorter runway (<3200 feet). Essentially, the antenna tower must rise no more than 1/100 the distance from the tower to the nearest edge of the runway if the runway is greater than 3200 feet long. If the runway is 3200 feet or less, the tower height may extend up to 1/50 the distance to the nearest edge of the runway.
Of course, the reason for the 20,000 feet (3.79 miles) horizontal range within which this calculation must be considered for a longer runway is due to the general location maximum allowable height of an amateur radio antenna structure without notifying the FAA and registering with the FCC… our question of interest.
When you are 20,000 feet from the nearest runway edge your tower may rise to 20,000 x 0.01 = 200 feet. Similarly, for the shorter runway case, if you are 10,000 feet from the runway the tower may rise 10,000 x 0.02 = 200 feet.
With a heliport, the slope defining the maximum antenna height is 25:1, or the antenna may be 1/25 of the distance to the nearest edge of the heliport. At exactly the 5000 feet distance within which this must be considered, the antenna may again rise up to 200 feet high.
So, if you’re not near the airport, 200 feet is your limit without getting entangled in government red tape. If you are near the airport, get out your measuring tape and calculator.
The answer to General Class question G1B01, “What is the maximum height above ground to which an antenna structure may be erected without requiring notification to the FAA and registration with the FCC, provided it is not at or near a public use airport?” is “C. 200 feet.”