What are counterpoises used for?
Apr 18, 2020 · How does a counterpoise work? The counterpoise functions as one plate of a large capacitor, with the conductive layers in the earth as the other plate. Since the radio frequency alternating currents from the transmitter can pass through a capacitor, the counterpoise functions as a low-resistance ground connection.
What is a counterpoise in radio?
May 01, 2008 · A simple explanation - a counterpoise is an extension conductor that connects the main ground grid to a remote grid or a ground electrode. It typically runs along with a overhead line, e.g.skywire or ground wire, and it helps the main grid to dissipate a fualt current by parallelling more ground conductors to the grid, hence reduce the GPR.
What is counterpoise (ground system)?
A counterpoise is a c onductor or system of conductors used an earth or ground substitute in antenna systems. When we look at how the word has been commonly used, we see general use and dictionary definition agrees. Model and Measurement Anomalies Average gain can be a useful tool in EZNEC, as can maximum or peak gain. This is how it is displayed:
How does a counterpoise antenna work?
Jul 30, 2018 · In order to use the soil as an effective counterpoise, we need to create a low impedance connection. This is done by creating a huge capacitor between the antenna and Mother Earth, where the radials act as one of the capacitor …
Does a counterpoise have to be straight?
Finally, the counterpoise does not have to be perfectly straight.Jul 30, 2018
Should a counterpoise be elevated?
Running elevated radials or counterpoises out of resonance is clearly a very bad idea, yet this is exactly what many installations, including some manufactured systems, do.
How long should a counterpoise wire be?
20-30 feetLength of counterpoise should be a minimum of 20-30 feet but longer is better. If possible run the counterpoise above ground away from or perpendicular to the antenna wire and do not ground the counterpoise at the unun. You can also use the unun with no counterpoise or ground if your feedline is at least 25+ feet long.
What is counterpoise wire and its use?
counterpoise, in electronics, portion of an antenna system that is composed of wires or other types of conductor arranged in a circular pattern at the base of the antenna at a certain distance above ground. Insulated from the ground, it forms the lower system of antenna conductors.
Do Counterpoises radiate?
Size. The size of the counterpoise used for radio work depends on the wavelength of the transmit frequency. With a monopole antenna, the counterpoise functions as a ground plane, reflecting the radio waves radiated downward by the antenna.
What's the difference between a radial and a counterpoise?
Radials hug the ground to help provide a low loss return path for the RF that is soaking into the ground. A counterpoise is used to create an artificial ground when an antenna is elevated.Nov 24, 2013
Does an end fed antenna need a counterpoise?
No, it is not needed, but it can improve the antenna system. An EFHW is simply a half-wave length of wire and a matching device, and that's it. Counterpoises are commonly added to shunt common mode reflections when operating outside of the wire's resonant frequency to avoid RFI issues ("RF in the shack").Dec 10, 2018
How does an end fed antenna work?
With end fed antennas, the coax is meant to radiate as part of the antenna system (serving as the “ground” or counterpoise) and therefore you need to use a Feed line Choke (BOX “FC” above) to suppress the common mode current on the outside of the coax feed line so it does not enter the radio and cause garbled ...
How do you make a UNUN 9 1?
3:529:21Building a 9:1 UNUN With FT-140-43 Toroid. - YouTubeYouTubeStart of suggested clipEnd of suggested clipThis way up to nine terms. So let's make sure they don't turn cross. Although I'm not sure that'sMoreThis way up to nine terms. So let's make sure they don't turn cross. Although I'm not sure that's important but it certainly makes it easier to identify.
What is a ham radio counterpoise?
A counterpoise is simply a long, insulated wire that attaches to the ground connection on your antenna tuner. The best counterpoise is 1/4-wavelength at the lowest frequency you intend to use. That's a lot of wire at, say, 3.5 MHz, but you can loop the wire around the room and hide it from view.
What is a counterpoise definition?
Definition of counterpoise (Entry 2 of 2) 1 : counterbalance. 2 : an equivalent power or force acting in opposition. 3 : a state of balance.
Why is counterpoise earthing used for DFR locations?
In some areas of high sensitivity soil such as rocky locations, earthing is used in the form of counterpoise earthing to bring down the resistance. These counterpoise wires are applied to reduce the resistance of the tower grounding device.
What is a counterpoise?
I'll have to differ. Counterpoise is a grounding electrode made up of buried wire, often used with transmission towers. "Continuous" counterpoise is sometimes used where the wire is buried continuously between towers.
What does the word "counterpoise" mean?
It may help if one knows how the word counterpoise was formed. It is French. And "Counter" means counter, exactly as in English. "Poise" means weight. So the word literally means "counterweight" and that is what a counterpoise is in an antenna system, where it was originally used.
What is a typical ground grid?
A typical ground grid would be in a substation with closed meshes. Typically counterpoise would be used on a transmission tower, especially if it is hard to drive ground rods. I don't know how common it is. I've always just used ground rods or used the tower pier foundations as a ufer ground.
How far apart are the ground rods in the Rbulsara?
In the electrical world of the USA, it is a grounding electride system consisting of three ground rods buried in ground roughly 10 feet apart from each other forming an triangle and connecting them with copper conductors.
What is the Portuguese word for counterpoise?
Just to let you know on the use of the term "counterpoise" (in Portuguese is "contrapeso"), is common practice in my company (Chesf, Northeast of Brazil) to use "contrapeso" to improve transmission lines grounding, mainly those with concrete towers. Regards,
Is a ring a closed loop?
Yes, the word "ring" or "closed loop" is the key. Since that kind of mimics the topology of a true counterpoise antenna grounding grid, perhaps the term 'counterpoise' was borrowed by some power (more likely the Tower people, who would be the common link between the antenna work and the power work).
What happens if you put an antenna low?
If the antenna is placed low, close to the ground, and the counterpoise is extended to one side, your antenna will display a fairly directional pattern – you can experiment to find what works best for you. Finally, it is important to remember that radials and counterpoise are two different things.
What happens if you use a resonant counterpoise?
One of the consequences of a resonant counterpoise is that the antenna radiation pattern will change depending on the location of the counterpoise.
How to tune a portable antenna?
Then tune your portable antenna to the lowest SWR you can achieve (depending on the antenna this is done by using different taps on the loading coil, sliding a sleeve, or adjusting the length of the antenna whip).
How to use soil as a counterpoise?
In order to use the soil as an effective counterpoise, we need to create a low impedance connection . This is done by creating a huge capacitor between the antenna and Mother Earth, where the radials act as one of the capacitor plates, and the soil below becomes the other . Logically, in order to achieve low impedance, we need high capacitance, ...
What happens to the antenna tip as the current bounces back?
As the current bounces back and force along the radiator, the tip of the antenna becomes alternately positively and negatively charged. In order to keep the feedpoint electrically neutral, something else must develop an equivalent opposite electric potential to the radiator tip.
What does the term "counterpoise" mean?
Probably the majority of people use the word counterpoise to refer to something similar to an elevated radial system (but not everyone does). Many people (and textbooks) use the word counterpoise to refer to a radial system , whether those radials are elevated or not. Other people use the terms interchangeably, so don't jump to the conclusion ...
How many radials are needed for an antenna?
Based on my experiments, 8 radials is probably the minimum you need, and some antennas may have as many as 100 radials. There is plenty of information about radials on the internet.
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An interesting statement reappears freqquently saying " a short counterpoise added to the end of end fed antenna affects common mode current " (on the outside of the shield of the coax _ added by me ).
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Not sure if I'm understanding your Q correctly, so my apology if I'm missing something. I'm sure I will be corrected if so
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As far as the "short" part of "short counterpoise" - note that an n-half-wave "antenna" wire exhibits a high-Z parallel-like resonance. When you plot input Z of the whole system of end-fed half-wave with counterpoise vs.
W6OGC Ham Member QRZ Page
As far as the "short" part of "short counterpoise" - note that an n-half-wave "antenna" wire exhibits a high-Z parallel-like resonance. When you plot input Z of the whole system of end-fed half-wave with counterpoise vs.
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It might help if you imagine replacing the counterpoise with a fixed capacitor. What to do with the other lead?
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Uhhh, that first chart doesn't make sense to me. Shouldn't the horizontal axis be in wavelength, not feet?
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Well, still not quite sure what you're getting at. It's not that connecting up the system in this way it's "gives us" an antenna that "has two parts".
What is a counterpoise wire?
H. Horizontal, unbalanced antennas, such as a long wire or random wire, need an RF Ground wire that should be 10-15% longer than the antenna wire itself. This is often called a counterpoise. The RF ground wire in this case can be laid out in many ways, just so long as it does not cross over itself to form a loop.
What is SGC Smartuner?
The SGC Smartuner gets energy into an antenna, but the design of an antenna is what controls what happens to the RF energy from there. For some antennas, the antenna is simply not complete without a radial system, or at least a counterpoise. Other types of antennas need no RF ground system at all. Most reference books on antennas provide solid ...
What are radials and counterpoises?
Radials and Counterpoises have two basic purposes: 1. To improve the RF ground conductivity for the ground current return path. Unless you live in a salt-water swamp, your ground conductivity makes a very poor path for the return of ground currents.
Why does Smartuner change the rules?
The Smartuner changes the rules because there is no single frequency that you will be operating on, so all of the thumb rules for 1⁄4 and 1⁄2 wavelength radials don’t apply . It is possible to be either a purist or a pragmatist in deciding what radials to put in place.
Is a radial system a counterpoise?
If the radial system is mounted above the ground, it is technically a counterpoise and takes the place of the actual ground. An equally good ground can be created by mounting well-bonded chicken wire or other grid material to form the ground plane near the antenna.
Do you need RF ground for a balanced antenna?
If the antenna is balanced, you don’t need an RF Ground. Dipoles and Loops are the most common forms of balanced antennas in use. With a properly installed antenna fed by a Smartuner at the feed point, no RF ground is necessary. B. If the antenna is unbalanced, a radial system or counterpoise is necessary for operation.
Do antennas need RF ground?
Other types of antennas need no RF ground system at all. Most reference books on antennas provide solid guidance on radials and counterpoises, but only for antennas cut to a specific frequency. When using an SGC Smartuner, the rules have to change because the Smartuner operates across the full range of HF frequencies.
How many inches is a counterpoise antenna wire?
You would construct a counterpoise antenna wire 11.5 inch for VHF, 6.5 for UHF and about 19.5 inches for an OK performing dual band VHF/UHF radio. Normally with a handheld radio the counterpoise (ground) is your own body as you are holding the HT. This is because the capacitance of your body makes a good counterpoise under normal conditions.
What is a ham radio called?
We found an interesting tip that might just improve the performance of those small affordable handheld ham radios called a “Handy Talky” or HT for short in ham vernacular. [RadioHamGuy] posted an interesting video on adding a counterpoise antenna wire to an HT. He claims it will noticeably improve both transmit and receive by making a quarter-wave monopole into a makeshift dipole antenna system.
What is the correct acronym for a hand held radio?
You are correct Scorinth, the correct term for the acronym “HT” is “Hand-held Transceiver”, or “Hand Transceiver” is also acceptable if you are orally lazy. “Walkie-Talkie” is a child’s term for a portable CB or other small unlicensed hand-held radio.
Does a wire counterpoise reduce loss?
Your body acts a counterpoise, and the antenna is somewhat tuned to have a decent impedance when it is held, but your body is a poor conductor so it’s lossy. Adding on the wire counterpoise will reduce the loss, but maybe change the impedance.
When was the SCR 536 made?
Yes John Mengel, the SCR-536 was developed in 1940 by Galvin Manufacturing. Which is now known as Motorola… so the original Handie-Talkie was Motorola but was not referred to by it’s developer name, just its official designation (SCR-536) or its common name used by soldiers and civilian alike – “Handie-Talkie”.
Can a HT antenna be a dipole?
On an HT, it does not usually make it into a dipole, as that would actually reduce its performance. Many HT whips (non-ducky) manage to scrounge up some nontrivial gain. same general idea, if you want to use a mag-mount antenna in the house, stick it to a cookie sheet or your refrigerator or something.
Overview
Size
The size of the counterpoise used for radio work depends on the wavelength of the transmit frequency. With a monopole antenna, the counterpoise functions as a ground plane, reflecting the radio waves radiated downward by the antenna. To perform adequately, the counterpoise should extend at least half a wavelength from the antenna tower in all directions. In designing a counterpoise for a medium-wave radio station, for example, radio-waves are a maximum of 566 …
Working principle
Counterpoises are typically used in antenna systems for radio transmitters where a good earth ground connection cannot be constructed.
Monopole antennas used at low frequencies, such as the mast radiator antennas used for AM broadcasting, require the radio transmitter to be electrically connected to the Earth under the antenna; this is called a ground (or earth). The ground must have a low electrical resistance, beca…
Use at low frequencies
The largest use of counterpoises is in transmitters on the low frequency (LF) and very low frequency (VLF) bands, as they are very sensitive to ground resistance. Because of the large wavelength of the radio waves, feasible antennas used at these frequencies are electrically short, their length is small compared to the fundamental resonant length at the operating frequency, which is one-quarter …
See also
• Monopole antenna
• Tesla coil
External links
• Papalexopoulos, A. D., Meliopoulos, A. P., "Frequency Dependent Characteristics of Grounding Systems". Power Delivery, IEEE Transactions, vol. 2 issue 4 (Oct. 1987), pp. 1073–1081