20 Meter 1/2 Wave Dipole. ALL STAINLESS With 1:1 Current Choke Built in 1kW

Description

Designed by Nelson Antennas (KD8UJM)
For maximum DX'ing on AM,CW or SSB
20 Meter Monobander
First
YOU MUST READ THE ENTIRE LISTING!!
The Half wave dipole has been considered one of the best all time antennas for both local and long distance DX contacts.
This 1/2 Wave dipole includes a built in custom built 1:1 current choke that isn't just a wide banded universal air core multi band balun but Ferrite and optimized for the 20 meter band frequency area. The balun will handle 1000 watts pep conservatively without issue. I do also have a 1500W legal limit version listed for just a few dollars more.
All Stainless steel hardware for many years of trouble free service. Built with 3" PVC, Stress reliefs on all stress points as you can see. Includes UV protected nylon dog-bone insulators. Standard but very high quality SO-239 connector to mate with your coax PL-259 coax connectors. The enclosure has a very small upward flowing air inlet hole with a tiny "weep hole" at the bottom ensuring condensation with temperature changes can always escape the system. Elements made with Marine 18 AWG tinned copper insulated wire can handle 2kW of power but also provide a nice thin/small footprint.
Depending on my stock, dog-bone insulators will either be white or gray.
This antenna will cover the entire 20m band with no tuner needed.
Power Handling                                              1kW PEP
Antenna Length                                              Approx 32 ft insulator end to end
Antenna True Gain                                         2.15dBi
Antenna Radiation Pattern                            Omnidirectional
Element Material                                            18 AWG Marine tinned copper insulated wire
As with any true 1/2 wave dipole, at 1/2 wavelength above ground a good dipole will have a 70 ohm impedance resulting in a 1.5:1 SWR and this antenna will still cover the entire band well under a 2.0:1 with ease and lobes will be determined by the users mounting height as well. Below are typical installation results you will see with this antenna as shipped.
ANTENNA HEIGHT ABOVE GROUND         SWR / FREQUENCY
APPROX 15 FEET UP=       1.15 @14.1700  1.5:[email protected]   1.5:[email protected]  2.0:[email protected]  2.0:[email protected]
APPROX 20 FEET UP=       1.38@ 14.220    1.5:[email protected]   1.5:[email protected]  2.0:[email protected]  2.0:[email protected]
APPROX 25 FEET UP=       1.5:[email protected]  2.0:[email protected]  2.0:[email protected]
How to deploy this antenna for maximum gain and desired SWR:
Remember, a dipoles feed point impedance changes with height above ground! For best match and performance please read the following;
To achieve highest gain and Best operation 1/2 wave dipole should be mounted 1/2 wavelength high. Although at lower than 1/2 wave you will obtain slightly better SWR as any proper dipole will do, you will get best DX type gain at 1/2 wave up. We recommend this antenna to be between 20 and 25 feet high for best SWR and gain. This will give the rf the best low angle radiation for long distance DX. It will work fine at lower heights especially if you desire better SWR.
The importance of a
proper
1:1 current choke on a dipole;
A resonant half-wave dipole is typically fed with coaxial feedline and tuned to a specific area of a band. Its planned use is generally within that band. A popular misconception is because the dipole is resonant, or because the dipole feedline is small in diameter, a 1:1 current type choke is not helpful. Current chokes isolate or add impedance to unwanted common-mode current paths, reducing or controlling common-mode current. Current choke/baluns are the balun of choice in all but very specialized situations, because they work better than voltage baluns in most real-world systems. Basically, they ensure that the currents on each side of the dipole (balanced antenna) are perfectly even. This also stops unwanted currents from flowing on the outside of the coax from the antenna element, (all coax is unbalanced line) and traveling back to your receiver.
This ensures a "clean" system without unwanted RFI issues from any noise the element may pick up.
Simple to deploy
The center of the antenna has a stainless eye-bolt at the top for it to hang from a support.  Pull each leg of the dipole straight out flat and secure by tying your cord/rope to the dog-bone insulators. If securing the antenna to objects like trees that will move in the wind be sure to use a cord material with some stretch. You can also leave just a bit of slack in the system.
As with ALL antennas, you should install them in an area as open as possible. Obstacles close to the antenna will have an affect on both the tune of the antenna and radiation pattern. You cannot mount this or any antenna up against walls and such.
Any questions? Please feel free to ask. I am adding many more antennas and other antenna related products to my eBay store so please check them out from time to time.