Discone Antenna 101 – All Your Questions Answered in One Place
Guess what helps you check the air traffic or track stations effectively? It's the Discone Antenna. Now, since you're here, we're guessing that you don't have much of a clue about this antenna at all.
In this Discone Antenna 101, we're going to break down every bit of the things you need to know about this piece of equipment. So, without further ado, let's dive in.
Discone Antenna 101
In this article, we have tried to answer every possible question about the Discone Antenna. So, let's get to it.
1. What Is a Discone Antenna Used for?
- Antennas have always been a way to ensure that transmissions of waves, such as radio signals or microwaves, can reach their destination.
Discone antenna is one such antenna. It can either be used for broadcasting purposes in the form of an omnidirectional wideband design or data transmission, where it has properties similar to those found with other antennas but on broader scales.
Discone antenna is known for its ability to imitate the shape of a cone, which makes it perfect as an all-purpose radio receiver.
For this reason, many people use them in communication applications, from scanning and monitoring commercial or military frequency ranges to home scanner enthusiast models that any individual can use with basic knowledge on how they work.
Discone antennas are a common choice for frequencies above 30 MHz, but on occasion, they can be used in the lower range of 10-30MHz.
This low-angle radiation is excellent for VHF / UHF applications since it has its most incredible sensitivity parallel or almost parallel to Earth's surface--and not at an elevated position in space like most antennas do.
Towards the top end of its bandwidth, though, it becomes apparent that this orientation gets more and more off-axis as you get closer towards either edge; but still usable nonetheless!
They're typically big and heavy, making them unsuitable for mobile or handheld devices; however, their design allows them to provide good signal reception over long distances!
2. How Does a Discone Antenna Work
The Discone antenna is a relatively complex model, but it can be simplified into an easy-to-understand version.
The circular disk and cone elements sufficiently simulate the electromagnetic energy of a full-size round object, such as that which one may see on top of many buildings or atop tall towers.
For this reason, more discs make for better simulation; however, there are some tradeoffs between building costs and wind resistance with too many discs close to each other.
Six disks will usually work well enough--the number isn't critical since they do not need to match anything outside their radius.
But you'll want them placed at least two feet apart from one another so as not to disturb any cones' ability to receive signals without any interference.
In Discone operation, feeder energy meets the RF antenna, which spreads over the surface of a cone.
From apex to base, it is possible for this radiated power to be efficiently directed towards or away from objects on Earth depending upon their distance about the height above ground level.
The most efficient radiation pattern occurs at low angles across an omnidirectional horizontal plane that maintains its orientation regardless of changes in frequency.
However, when higher frequencies are considered, there is some degradation due to multipath interference effects such as diffraction around obstacles, resulting in increased reflection of buildings.
Discone antenna is known as a resonant antenna. It has the feed point on top of it, and at that position, current maximum issues are also found there.
Below its minimum frequency level, an RF match to 50-ohm coaxial cable becomes very bad. Still, once the frequency rises above this point, it gets reasonable matching across all frequencies in the range of operation or bandwidth.
The design makes installation easier and it does not require any external components like the monopole tower antennas do. It also saves precious land space by being self-contained with no need for ground connection.
The last two features make up some advantages over these types and others like omnidirectional half-wave dipole due to higher gain factor because they have more surface area when compared side by side.
3. Are Discone Antennas Any Good
- Discone antennas are an excellent option for any user with a need for wide bandwidth reception.
These antennas can handle 10:1 of the spectrum, making them perfect solutions to cover bands like scanners and many other applications.
Discone antennas have proved to be far better than what was said in the past for hobbyists or professional use because there may not always be a reason they should not transmit.
If it can provide such high-quality transmission across different bands with little interference from outside sources, that could distort sound quality.
Discone antennas are often overlooked for monitoring and radio scanning because they cannot transmit.
They are typically only used as a receiver of RF waves, but with their beaming pattern close to perfect 360 degrees, there isn't much else you could want from them!
Discone antennas are ideal for VHF and UHF applications such as police, firefighting, geology exploration, and radio astronomy.
The radiation angle increases slightly at the top of the antenna's frequency range, which means that its reception is highly sensitive in helping discover natural resources underground or find emergencies nearby; it also helps track geological changes on Earth's surface.
4. What Is the Working Procedure of a Discone Antenna?
- A Discone antenna may be the most efficient and popular radio frequency (RF) antenna. The design includes a disk, cone, and insulator to produce an RF signal in all directions.
According to various sources on how it should look, the disk's diameter is typically 0.7 times that of its operating quarter wavelength; if you want your frequencies from 150-200 MHz, then use 1-inch disks with 2 inches between them placed 8 feet apart).
A reasonable length for this configuration would be one-quarter wavelength at 160 meters long or 16 meters high).
Some structures have more than two cones stacked together called "stacked discs," so they can cover three wavelengths at 80 watts each! Lower height will give better frequency.
The angle of the cone or rods making up a de facto Discone antenna can vary from 25 to 40 degrees. The shape and insulator must be separated by an air gap to not interact, which would otherwise distort reception at higher frequencies.
At low-frequency ranges like 100 MHz, where there is less interference on both sides of the wavelength (the front end is empty), performance in gain and bandwidth are similar for these antennas as it is for ground plane antennas such as patches.
But this changes once you get into a high-frequency range around 1 GHz because electromagnetic waves will bounce off conductive surfaces nearby - significantly if their properties change suddenly in some way via something called "reflection" when light bounces off different objects.
5. How to Calculate Discone Antenna
- The first step in calculating a Discone antenna is to measure the desired frequency, which should be tuned for optimal performance.
Next, calculate the dimensions of both discs and find their surface areas using either trigonometry or multiplying each side length times Pi.
Now that you have your two different-sized circles (the smaller inner circle will always be one diameter shorter than the outer), it's time to figure out how many radials per inch are there on each size unit.
This can easily be accomplished through some long division with pencil and paper: Divide 360 degrees into pi until you arrive at an answer close enough to 1/4th of a degree; then divide again as necessary so that any fractional digits after decimal points cancel out when dividing back.
Now combine all the calculations, and you will get your desired result!
6. How to Adjust a Discone Antenna
- To adjust a Discone antenna, you first need to verify that the cone is not too low and has space for additional height adjustments.
To do this, place your hand on top of the cone with fingers extended as if you were holding an apple or other round object.
If there are one or more gaps between your fingertips and the bottom edge of the dish - it can be adjusted higher.
You will see adjusting screws at the base, which can then be used to raise them by turning the left/right screwdriver until satisfied with levelness from the top view (don't get into obsessive tweaking here).
If you're not a professional in the field, it can be hard to figure out how to adjust your Discone antenna. Luckily, there's an easy solution: refer to the manual that comes with this type of antenna!
7. How to Install and Mount a Discone Antenna
- The height of the antenna will make a difference to line-of-sight comms. A house in the way is usually minimal disruption, but if your antenna cannot see past places around you, then it may not be able to pick up signals or have enough range for coverage.
It may also create noise from other sources that can disrupt signal transmission and reception.
The best thing would be an elevated mount as high as possible, so there isn't any interference with anything nearby - this could even include getting rid of trees too close by!
Do not worry about impedance mismatch. Discone antennas and receivers do not have constant input impedances across the spectrum, so any slight difference in coax is irrelevant.
It will also be cheaper than most other cables that are readily available at your local hardware store, which means you can buy it off the spool to make installation even easier on yourself!
You will, of course, need adapters for adapting your Discone antennas or receivers to fit with different connectors.
However, this is, fortunately, an easy process involving only two connections per device (so long as these devices were made within five years).
An old coaxial TV cable can be used to help amplify and split signals for your Discone antenna.
The wires are harder to come by, but they cover a frequency range from 70 MHz - 800MHz (up until the digital transition), which is great if you're interested in getting multiple channels using that kind of signal.
If you want higher frequencies, an active or passive device with amplifiers targeted at specific areas may work better for what you need!
8. How to Make a Discone Antenna for RTL-SDR
- The first step to building a Discone antenna for RTL-SDR is securing the items needed, such as copper wire, solderless breadboard wires, and an RTL-SDR. Next, you'll need to create two types of coils that will serve as directors or reflectors.
One type can be made by connecting eight pieces parallel on each side with six inches between them, while another option is to touch 12 sides in series, spaced out equally over five feet.
To ensure everything is correctly connected, use caution when working near any metal objects, so it doesn't short circuit anything!
The final steps involve making connections from all connectors outputting electricity into screws inserted through holes at the end opposite where they're connected, then plugging them together.
Discone Antenna vs. Dipole
Like Discone, Dipole Antenna is getting famous as well. If you're confused about whether to go for Discone or Dipole, you better know their differences a bit.
Discone Antenna
A Discone antenna is not like other antennas, where both cones are replaced with a disk. The disk will only be on top of one cone as opposed to the two in biconical antennas.
An actual Discone antenna consists of a solid metal cone and disk. In this case, it can cover two octaves of bandwidth, which is helpful for hobbyists that want to listen in on different bands like 140-500 MHz without interference from others within the same range.
However, many people use discs with rods connecting them instead as they are cheaper than cones/disks made out of all one type of material.
Compared to lossy performance, these antennas are less effective at high frequencies such as 54MHz when used with vertical whip antennas.
If you use spoke instead of metal-made cones, it reduces wind loading and makes the construction easy. That's why Discone antennas are so popular with amateur radio operators.
You can make the spokes or ribs with any stiff wire you have lying around; for example, brazing rods will work wonders if you happen to be an avid gardener like me!
They are usually made out of solid sheet metal, which is why they're so ideal for VHF or UHF applications that take place near the ground level, where there's better access to signals.
The radiation angle increases slightly at the maximum frequency range, meaning Discones make great indoor Wi-Fi antennas because wireless frequencies often happen in this bandwidth (UNAVCO).
Dipole Antenna
The dipole antenna is a very common kind of RF antenna. The basic design for the dipole can be used on its own, or it can work with an array to form one, which is a more complicated type of radio communication aerial.
This antenna has been widely applied in HF, VHF, and UHF sections as either the radiating elements or driven elements, depending on what you need at that time. It takes little effort to construct this simple device.
The dipole antenna is a standard and versatile design for receiving balanced signals with minimal interference.
This two-pole device can pick up frequencies from both high and low, so they're perfect for anyone looking to listen in on conversations that cover different topics without having the sound quality suffer or face any problems due to conflicting transmissions.
The primary TV-top antenna is nowhere near as powerful as the more advanced options like the folded dipole. These antennas are much less bulky and offer a better signal-to-noise ratio than their predecessors do.
Folded dipoles have ends that turn back toward the center, which helps maximize signal strength - this makes them aesthetically pleasing and highly functional!
Half-wave and half-wave folded dipoles work well for those who live in apartment buildings or high-rise condominiums. There, space is limited because they don't need an entire room dedicated to receiving signals from the satellite dish or outdoor aerial array.
Discone Antenna vs. Ground Plane
The ground plane works better on the frequency range it is tuned to, but if you're looking at an all-inclusive type of antenna, they work equally well. The problem with using both, though, is how they perform.
While in general, one will be better than the other depending on what frequencies you want them each listening for, their performance might vary too much, so there's no telling which would do better when used together.
Discone Antenna Dimensions
The Discone antenna is a versatile design used to transmit frequencies ranging from 10 kHz to 1 GHz.
It can be less efficient than other antennas designed for specific frequency ranges. However, it's still a practical option when you need coverage across multiple octaves of frequencies like high-frequency bands and low-frequency ones alike.
The three main parts include the disc, which gathers radio waves to send them through the cone, where they are then amplified before finally radiating out into space with the help of one last component, the insulator.
Disc
The disc of a Discone antenna should have an overall diameter equal to 0.7 times the wavelength of its lowest frequency - this will ensure optimum performance and efficiency.
Besides, the feed point for these antennas is at the center, where they're fed with a coaxial cable containing 50-ohm impedance matching networks to provide maximum connectivity;
One conductor connects directly from the central region via wire or fiber optic line, while another extends up through the cone, which serves as a reflector dish.
Cone
A Discone antenna is designed to have a cone angle that varies from 25-40 degrees. The lower the frequency, the greater the length needed for its corresponding quarter wavelength, which will dictate size and direction accordingly.
Insulator
The Discone antenna is a popular design for high-frequency ranges. Separating the disc and cone with an insulator will affect some important properties, especially at frequencies close to the limits of this type of radio design.
Discone Antenna Poor Reception
It's often said that Discone antennas have poor reception, but this isn't necessarily true. Typically, a Discone antenna is more sensitive to high frequencies than lower ones, and so they tend to pick up stronger signals in the higher frequency ranges.
However, other factors at play beyond sensitivity determine how good an antenna will be for you specifically - such as where your nearest transmitter tower is located or what type of interference might exist nearby (such as those from power lines).
Discone Antenna Frequency Range
Discone antennas are omnidirectional and wideband, allowing them to cover a frequency range with ratios of 10:1.
This means the antenna is also wideband! You could purchase an omnidirectional Discone with a 30-1300 MHz range, making it one of few available for such high bandwidths.
Wrapping Up!
Well, that was pretty much everything on the Discone antenna 101. Now that you've done your homework on this antenna completely, you can do your math on whether it will be useful for you or not.
