2 Meter Skeleton Slot Antenna
- 2 Meter Skeleton Slot Antenna Adapter
- 2 Meter Skeleton Slot Antenna Booster
- 2 Meter Skeleton Slot Antennas
- 2 Meter Skeleton Slot Antenna Mounts
On a vehicle with a steel body and roof, the most feasible 2 meter slot antenna design is a pair of square flat plates with spacers to maintain the space between them. The slot ends up being the horizontal space between the plates. Finished the antenna today with the updated dimensions and I am resonant at 152.4 mhz. Checking the 2 meter portion gives me a SWR of 4.2 It was a fun build, but just curious how your guys' cube came out. Dave Dec 28th 2018, 19:56: AD6ZH Joined: Jul 16th 2001, 00:00 Total Topics: 0 Total Posts: 0. The skeleton slot antenna is very cheap and simple to make - mine consists of three bamboo spreaders and copper wire!! It is fed in the middle of the center wire with open wire line which is taken to an antenna tuning unit in the shack. They sold single band and tri-band models plus swiss quads, and big 50, 144, and 432 Mhz antennas. One is the skeleton slot big 2 meter array and VHF quagi's. I looked Louis up and he is listed now as KG6UH with an APO address so he is either military or civilian military contractor.
- Antenna Theory Tutorial
- Antenna Basic Terms
- Types of Antennas
- Antenna Arrays
- Wave Propagation
- Antenna Theory Useful Resources
- Selected Reading
Slot Antenna is an example of Aperture antenna. A rectangular slot is made on the conducting sheet. These slot antennas can be formed by simply making a cut on the surface, where they are mounted on.
Frequency Range
The frequency range used for the application of Slot antenna is 300 MHz to 30 GHz. It works in UHF and SHF frequency ranges.
Construction & Working of Slot Antennas
The use of slot antennas is well understood through its working principle. Let us have a look at the structure of a slot antenna.
When an infinite conducting sheet is made a rectangular cut and the fields are excited in the aperture (which is called as a slot), it is termed as Slot antenna. This can be understood by observing the image of a slot antenna. The following image shows the model of a Slot antenna.
The working of Slot Antenna can be easily understood through Babinet’s principle of optics. This concept gives an introduction to the slot antennas.
Babinet’s Principle
Babinet’s principle states that- “When the field behind a screen with an opening is added to the field of a complementary structure, the sum is equal to the field when there is no screen”.
The above images clearly explain the principle. In all the regions, which are non-collinear with the beam, the above two screens, in figures 1 & 2, produce the same diffraction pattern.
Case 1 − Consider a light source and a conducting plane (field) with an aperture before a screen. The light does not pass through the opaque area, but passes through the aperture.
Case 2 − Consider the light source and a conducting plane of the size of the aperture in the previous case, being held against the screen. The light does not pass through the plane but through the remaining portion.
Case 3 − Combine these two conducting planes of both the cases and put before the light source. The screen is not placed to observe the resultant combination. The effect of screen gets nullified.
Working of Slot Antenna
This principle of optics is applied to electromagnetic waves for the wave to get radiated. It is true that when a HF field exists across a narrow slot in a conducting plane, the energy is radiated.
The image shows a slot antenna, which explains well about its working.
Consider an infinite plane conducting screen is taken and pierced with apertures of desired shape and size and this will be the screen of slot antenna. Another screen is considered interchanging the places of aperture and screen area which is the complementary screen.
These two screens are said to be complementary as they result in complete infinte metal screen. Now, this becomes the slot antenna. The terminal impedance is quite desirable for the radiation.
Radiation Pattern
The radiation pattern of the Slot antenna is Omni-directional, just like a half-wave dipole antenna. Take a look at the following illustration. It shows the radiation pattern of Slot antenna drawn in Horizontal and Vertical planes respectively
Advantages
2 Meter Skeleton Slot Antenna Adapter
The following are the advantages of Slot antenna −
- It can be fabricated and concealed within metallic objects
- It can provide covert communications with a small transmitter
Disadvantages
The following are the disadvantages of Slot antenna −
- Higher cross-polarization levels
- Lower radiation efficiency
2 Meter Skeleton Slot Antenna Booster
Applications
The following are the applications of Slot antenna −
- Usually for radar navigational purposes
- Used as an array fed by a wave guide
Anyone ever heard of J-BEAM or SLOT-BEAM Yagi antenna's?
I have one here, it's quite an oldie. The one I've got is a 18 element
(including driver and reflector) for 70 cm. The driver looks lika a kind of
'stacked folded dipole':
+------------------------+
+--------o o---------+
+------------------------+
The two 'dipoles' are not 180 degrees but slightly less:
O
O
/
/
O
The reflector is similar shape as the driver, but both 'dipoles' are in a
straight line (180 degrees).
O
O
O
Strange things are: all the directors are of the same length and the width
is bigger than the dipole/reflector width. The dipoles seem a bit small
comparing to a ordinary folded 70 cm dipole. At first I thought it was an
antenna for higher frequencies, but the guy I bought it from ensures me he
used it several years for 70 cm (I believe him! He's a nice guy and I got
the stuff for 'an apple and an egg' so why should he lie?). I don't know
exactly what kind of balun I should provide this beauty with? It's got a
balun inside but it's a bit rosty so want to replace it by a new one.
I cleaned the aluminum (it's nice and shiny now, like new).. It's a very
impressive antenna.. but does it WORK? Anyone got any info on it while I'm
working at the 3-meter-boom-beast?
Please reply ONLY via email to: PD1...@AMSAT.ORG
73, Pleun
2 Meter Skeleton Slot Antennas
P.S. (Dutch): Dit bericht was in het Engels omdat ik het ook in andere
internationale newsgroepen heb gepost. Als iemand informatie heeft over de
J-beam of Slot-beam en het bericht niet helemaal begrijpt dan wil ik gerust
even een vertalingkje sturen.