How does MFJ 939 work? MFJ-939 uniquely measures your antenna’s complex impedance (R, X), computes the L-network and snaps in needed components for instant matching.
How do you use a MFJ antenna tuner?
What is an automatic antenna tuner?
An antenna tuner (and any of the names in the list below) is a device that is inserted between a radio transmitter and its antenna; when properly adjusted (tuned) it improves power transfer by matching the impedance of the radio to the impedance of the antenna, as it appears end of the feedline connected to the antenna
How do you use an automatic antenna tuner?
How do you use MFJ 941E?
Related advise for How Does MFJ 939 Work?
How do you use MFJ?
Do I need an antenna tuner with an amplifier?
Yes, you'll need an external tuner, unless your antenna is already matched sufficiently well to 50 ohms. The objective of the tuner is to transform the impedance seen by some signal source, like your radio, or the amplifier.
Does an antenna tuner help transmission?
The antenna tuner DOES increase the power transferred from the transmitter to the transmission line and therefore increases the power radiated from the antenna. The antenna tuner does not reduce the portion of signal lost in the transmission line.
Where is the HF antenna located on the most of aircraft?
The long wire antenna is used when the HF coupler is located in the forward part of the aircraft. The long wire provides maximum signal radiation off the sides of the aircraft and exhibit good efficiency even at the lower frequencies. Nulls in signal strength may be experienced off the nose and tail of the aircraft.
Does an antenna tuner help reception?
Member. Your right, an antenna tuner WILL help you on receive. The radio is going to work better receiving off a 50 ohm in feed. In fact, most guys with antenna tuners will use the noise floor or a received signal to begin tuning their antenna tuner.
How do I choose an antenna tuner?
Select the one that gives the best range, etc. Different antenna tuners will be able to provide a match over different ranges. Examples include the MFJ928 and MFJ939 which both provide a match over the range 6 to 1600Ω. Other antenna tuners will be able to match over different ranges so a judgement needs to be made.
Where do you put the SWR meter?
How do HF antennas work?
Antennas for transmitting skywaves are typically made from horizontal dipoles or bottom-fed loops, both of which emit horizontally polarized waves. For frequencies in the upper HF band, the ground is a better reflector of horizontally polarized waves, and better absorber of power from vertically polarized waves.
How do you measure antenna resonance?
In common with other measurements for measuring the resonant frequency of a tuned circuit the basic idea is to couple the coil of the meter to the circuit under test. When the meter is tuned to the resonant frequency of the antenna then the meter current will dip.
Do I need antenna analyzer?
An antenna analyzer is not necessary. Sure, it's handy. A VNA is even handier. For this equipment you're looking at something like $50 USD for a NanoVNA, up to many thousands of dollars for a lab grade VNA.
How does an antenna Analyser work?
Many transmitters include an SWR meter in the output circuits which works by measuring the reflected wave from the antenna back to the transmitter, which is minimal when the antenna is matched. Reflected power from a badly tuned antenna can present an improper load at the transmitter which can damage it.
Does SWR meter go before or after antenna tuner?
In practice, the SWR bridge should go between the radio and the tuner, and the tuner adjusted to provide a low SWR to the transmitter. BUT, all that means is that the transmitter is transferring maximum power to the tuner; you can still have a high SWR with considerable loss between the tuner and antenna.
Do UHF antennas need tuning?
All Mobile One UHF Antennas do not need to be tuned, they are very broad-band and will have a SWR below 1.5 to 1 as long as they are installed correctly.
What is VHF UHF antenna?
VHF antennas and UHF antennas use very high frequency (VHF) and ultra-high frequency (UHF) signals for two-way radio, public safety, and commercial communications. VHF is the range of radio frequency (RF) signals from 30 to 300 MHz. UHF is the range between 300 MHz and 3 GHz.
What is the ATU ham radio?
An antenna tuning unit, ATU or antenna tuner is an item consisting of inductors and capacitors that is used to tune an antenna so that it matches the feeder and reduces the SWR.
What is antenna Balun?
A balun (balanced line to unbalanced line) is a device that transforms a balanced transmission line to an unbalanced transmission line. Baluns are hooked up to antenna systems to help electricity run smoothly from the ground to the device.
What is SWR ham radio?
SWR, also known as Standing Wave Radio, is an important concept for ham radio operators. SWR is what allows us to know whether our antenna is performing as designed. If you have a good SWR reading, you can rest easy knowing your antenna is receiving and transmitting the best that it can.
What freq is HF?
High frequency (HF) is the ITU-designated range of radio frequency electromagnetic waves (radio waves) between 3 and 30 MHz. It is also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters (ten to one hundred metres).
What HF frequency is best?
HF users have found that using a frequency that is the MUF times 0.85 gives the best chance for good results. This is called the frequency of optimum transmission (FOT).
Do aircraft still use HF radio?
Modern aircraft now have an array of communication devices from the rudimentary HF radios of old to sophisticated satellite-based systems that enable us to talk almost as if we were on a mobile phone.
Does coax length affect SWR?
As the reflected wave travels back up the cable, it adds to the magnitude of the incident wave where it arrives in-phase with it, and subtracts from the magnitude of the incident wave where it arrives out of phase with it.
What happens if you transmit without an antenna?
Quite possibly no damage would have occurred. Most modern radios have foldback protection. When they sense high voltage from poor SWR they automatically reduce power to protect the finals.
What's the best antenna tuner?
10 Best Antenna Tuners Reviews in 2021
How do you use a HF antenna tuner?
Do you need an antenna tuner for VHF?
On the VHF/UHF bands, antenna bandwidth is not as much of an issue. A 2 meter antenna with 7% SWR bandwidth (nominal bandwidth for a Yagi), will easily cover the whole 2 meter band with a reasonable SWR. So if the antenna is tuned properly, no tuner is needed.
Do I need an SWR meter?
To tune your antenna, you will need to use a SWR meter. This device is attached between your antenna and radio. This device measures the amount of signal being reflected into your transmitter to help you measure the quality of your outgoing broad cast as well as any potential threat to your radio.
Are all SWR meters the same?
You are correct - they are designed to cover specific frequency ranges. If you are (or know someone who is) handy with a soldering iron - you can modify a CB SWR meter to cover the range 1Mhz to well above 1Ghz at low power.
Can I leave my SWR meter in line?
You could leave the SWR meter connected in-line, but you have to have a way to secure it so it's not bouncing around and it's out of the way. Really, if you can access the connections on the back of your CB, it's easy enough to connect the meter to calibrate your antenna and then remove it.
How far can HF transmit?
But the real advantage of HF is skywave propagation, where a single link can span distances as great as 3,000 km (a little less than 1,900 miles). Skywave propagation occurs when the radio wave is refracted (bent) in the uppermost layer of the atmosphere, called the ionosphere.
What is the difference between VHF and HF?
VHF operates at a higher frequency range than HF, usually between 30-300 MHz. These transmissions, due to their higher frequency, penetrate through the Ionosphere, with little or no refraction. VHF propagation is 'line of sight' in nature and so is restricted to shorter-range communications.