Questions tagged [antenna-tuner]

Questions relating to the setup and use of antenna tuners, the virtues and shortcomings of various types of tuners, etc.

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3 answers
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generic antenna tuner term: impedance matching vs real tuner

Generally, an antenna tuner is nothing more than an impedance matcher. Badly termed, as it does not tunes any antenna. For loop antennas though this is not the case. The antenna tuner does not do any ...
3 votes
4 answers
947 views

Help designing a random wire antenna to work with my tuner

I recently picked up an Icom M802 marine HF radio that includes ham bands and an Icom AT-140 antenna tuner. I have a ham license, but have been away from HF for many years and have never used a random ...
1 vote
1 answer
569 views

IC-7300 internal tuner failing when before tuning I have a 1.5:1 SWR?

I have an IC-7300 and have tried it with a couple of antennas. In each case the internal tuner works sometimes, and not others. That is not a surprise in itself, but sometimes when the untuned SWR is ...
0 votes
0 answers
35 views

homebrew t match atu issues

my homemade tmatch atu is ok on 80+40m but seems too have too mutch inductance on the bands above 40m,it has a 50mm/20cm roller coaster,i have a 40m doublet+ 4-1 balun+ common mode choke fitted in the ...
3 votes
1 answer
473 views

MFJ-939 not working with FT-450 - TUNE blinking

I have recently bought second hand MFJ-939Y for FT-450/950. I have Yaesu FT-450 (plain, without D or AT). Since the tuner did not come with a cable, I have built my own. (I am 33yo IT engineer with ...
2 votes
3 answers
6k views

Ideal Doublet Size 160-10 Meters

Is there considered an ideal / optimum length for a doublet for use on 160-10 meters when fed with open-wire feedline and a balanced tuner in the shack?
3 votes
1 answer
121 views

Low power indicated on tuner

Please forgive my extremely basic question, I am brand new on HF and have issues with my setup. I have a Chameleon MPAS antenna in vertical configuration connected to an AT-100 ProII tuner with a 50 ...
1 vote
2 answers
275 views

What is the difference between LC(CL) and CLC antenna tuning unit as power loss is concerned?

What is the difference between LC(CL) and CLC antenna tuning unit as power loss is concerned ?
5 votes
6 answers
2k views

Does an antenna pick up signals of all frequencies or only its resonant frequency?

I heard that an antenna picks up signals of all frequencies, and then these signals are filtered by a circuit using an inductor and capacitor, and that this is how a radio is tuned. However, I also ...
4 votes
1 answer
659 views

Using NanoVNA to tune antenna

I'm extremely new to this, so I'm mostly asking for tutorials and so on. I have tried configuring the device according to one tutorial I found. When I hook up the cheap antennas that came with a ...
3 votes
2 answers
216 views

Does a halfwave (or multiple) length of coax duplicate the load impedance of one end at the other end?

Ignoring the possibility of multiple radiators and phasing harness(es), consider the following example: If I have a short inductor-loaded vertical antenna that I have not carefully matched to 50 ohm ...
16 votes
12 answers
19k views

How can I safely transmit without an antenna tuner or SWR meter?

Just what the title says. An Antenna Tuner, henceforth AT, is almost a de facto piece of equipment in a shack; working the bands without one is tantamount to leaping off the diving board into a ...
3 votes
2 answers
785 views

HF Vertical antenna with no radial and loading coil but only ATU for 80m to 10m in a boat

I am new to HF antenna designs. I want to build an antenna for my fishing boat. My question is - if I use an ATU (like the ATU-100) and a 10m aluminium pipe as an antenna and fix it with a mast, will ...
6 votes
2 answers
353 views

Why does capacitive loose coupling increase selectivity?

There are multiple ways to couple antennas. It is said that an antenna is capacitive loose coupled if a small capacitor is used between the antenna and the parallel resonant circuit (like C2 in the ...
3 votes
4 answers
232 views

Is it worse to use an antenna tuner on an already-loaded short monopole?

If I had a good transmatch and wanted to use a spare CB antenna on the amateur HF bands, would I be better off bypassing its tuning coil completely? One ham pastime is using an antenna tuner to match ...
1 vote
0 answers
528 views

Help understanding Kenwood AT-230 tuner topology

Can you help me understand what the topology of my Kenwood antenna tuner is trying to do and what it might be compared to? Below is the schematic of my Kenwood AT-230 antenna tuner, and below that ...
3 votes
1 answer
368 views

Is there a name for this specific variation of L-match tuner (somewhere between L-match and Π-match) and what would be its advantages over L-match?

So I've been looking at the internals of the Icom AT-141 end-fed antenna tuner which I have, and I've noticed that it has some sort of pre-tuning LC stage before its traditional L-tuner network. ...
13 votes
4 answers
4k views

What is an antenna tuner? Why bother with resonant antennas in the first place?

There are a lot of antenna tuners on the market that have various capabilities in terms of how they can allow random radiators to work with our transceivers. What exactly do they do? My ...
2 votes
1 answer
203 views

Reasons for an antenna tuner at the transmitter other than transmitter protection?

An antenna tuner colocated with the transmitter may be required to prevent transmitting into an SWR higher than the allowed specification for the transmitter, or if the transmitter might overheat or &...
5 votes
5 answers
390 views

Antenna tuner at the transceiver output confusion

I am a bit confused. Let's take a HF transceiver for example. My understanding is that the output impedance of the transmitter is 50 ohms. The impedance of the coaxial cable feedline is 50 ohms, and ...
5 votes
2 answers
388 views

Is tuning at all useful for an antenna that is already resonant?

Say you have a resonant antenna that also has a tuner. Does this help at all? Can your antenna be "fine tuned" ?
8 votes
4 answers
828 views

Tuner at antenna side versus transmitter?

I figure the transmitter has a 50-ohm pure resistive output and that the transmission line is 50-ohm as well. I think it's usually the antenna itself that actually needs to be tuned, yet it sounds ...
3 votes
3 answers
2k views

SWR of 1.5 -- use internal antenna tuner or not?

My IC-7300 has an internal antenna tuner that can handle a SWR of up to 3:1. The other day I noticed that a frequency I was transmitting on (the 40m FT8 frequency FWIW) has an SWR of 1.5 (was my first ...
1 vote
3 answers
764 views

SWR erratic based on time of day

I have an odd issue - SWR swings wildly, like a loose connection (there are no loose connections), on 17 and 15 M, only mid-afternoon local. I have made contacts as far as Japan (from central NC) at ...
0 votes
3 answers
246 views

What happens to the signal level if the antenna has high SWR?

I'm currently reading "Reflections: Transmission Lines and Antennas" by M. Walter Maxwell, W2DU. This book explains well why the energy is not lost because of high SWR during transmitting, ...
1 vote
1 answer
175 views

Antenna Tuner Range

I have a Kenwood TS-480S and a Kenwood TS-870S both with built in antenna tuners. On the TS-870S I have a ZS6BKW multiband antenna and on the TS-480S I have a vertical whip with two counterpoise lines ...
0 votes
1 answer
72 views

Estimating SWR based on multiples of resonant length

I am planning to buy a Xiegu G90. It has an internal tuner that can tune up to SWR 5:1. Does anyone know if I have a resonant antenna on 40m, what I will have for a SWR on 80m?
1 vote
1 answer
85 views

Need way to indicate when rotary inductor reached its limit switches on a remote homebrew motorized hf tuner

I have a homebrew motorized hf tuner which is controlled by coupling dc from the shack through two BiasTs - one topside, the other in the shack. As I reverse polarity to adjust tuner, will two LEDs, ...
1 vote
1 answer
702 views

What may be damaged when using an internal antenna tuner on SWR above 3?

The Kenwood TS-570S comes with a warning against using the internal antenna tuner for antennas with SWR > 3, even though it may tune (e.g. at SWR 3.5 or 4). It says the transceiver or antenna may ...
2 votes
5 answers
5k views

Balun and tuner configuration for multiband dipole

I'm putting up a multiband dipole in some tall trees. (Perhaps it's more correct to call it a "dipole-doublet"). The situation I'm imagining looks like this: The legs of the antenna are each 100 ...
1 vote
1 answer
57 views

Bidirectional motor control using MFJ-4116 with RCS-4

I have the RCS-4 with two MFJ-4116. Prior to installing my motorized HF antenna system topside, I bench-tested the core of the assembly in my shack. The MFJ-4116 near my transceiver was injected with ...
3 votes
3 answers
3k views

Yaesu FT-891: power drops to 50% when TNR is ON and SWR is 1.5:1

I noticed a weird behavior of my Yaesu FT-891 transceiver. I'm using it with an external autotuner mAT-30 (120W SSB/CW, 30W PSK31), which is compatible with Yaesu FC-50. When I connect a 100W 50 Ohm ...
5 votes
5 answers
973 views

How can a tuner pick up a specific frequency?

The point I'm confused about is the antenna. Depending on the environment, there are tons of different frequencies passing through you (FM, AM, 4G, SAT, etc). The electrons in the wire will move as ...
2 votes
1 answer
942 views

Should I bother with a doublet if I can't go straight to the tuner with open wire?

I have two trees about 135 feet apart and about 55 to 65 feet tall. I have been trying to determine which kind of wire antenna to put up there. Initially I was considering either a fan dipole or ...
0 votes
2 answers
362 views

Built-in ATU vs Remote?

I have two antennas in my station: a 10-15-20M yagi, and a loaded 40M vertical. With the ATU built into my Kenwood TS-450S I can operate 80, 60 a and 30M with the 40M vertical too. Though, in 80M I ...
1 vote
4 answers
2k views

Can I splice a random wire antenna?

I have an Icom AH-4 with a random wire antenna. I have a fence around my property that is 60 feet long by 70 feet wide. The outdoor tuner is placed at the begining of the 60 foot section which leads ...
0 votes
1 answer
222 views

Problem with mAT30 ATU and FT-450D transceiver

Does this tuner work with this transceiver? Would appreciate response as I cannot get it to work!
4 votes
3 answers
4k views

Do I need an 9:1 UNUN for a half-wave end fed?

I was using a 10-ish meter wire as my HF rx antenna. That's all I can install in my QTH. However I realised that my ~10 m wire can be turned into an end fed dipole for 20 meter band. But there is a ...
4 votes
3 answers
7k views

Antenna tuner design

In a related question about a broadband antenna for SDR it was suggested me to build or buy an antenna tuner. Since maybe it was not clear to everybody, I'm designing an antenna tuner for reception, ...
1 vote
3 answers
290 views

Do I always need a tuner at both ends of the transmission line or is that only for certain types of antennas/circumstances?

Last night was my first night on the air as a General licensee and at HF. I've got an IC-7300 with the built-in antenna tuner. I'm pretty sure I understand how to operate the radio, for the most part. ...
4 votes
1 answer
420 views

Does an antenna tuner remove standing waves from a transmission line?

Does an antenna tuner remove standing waves from a transmission line ?
4 votes
2 answers
398 views

Pi Matching circut for tube PA - what values?

I am working on my 80m and 40m CW transmitter and ran into a problem: I need to match the high impedance of PL504 to 50ohm coax, a Pi match seems to be the best, but I don't know how to calculate ...
9 votes
2 answers
2k views

What types of materials increase the inductance of a coil when inserted inside it?

I'm asking this because of the comments in this answer, that imply that steel (mostly iron) has similar characteristics to ferrite. Specifically, it is implied that inserting solid steel into a ...
8 votes
4 answers
2k views

Two Antenna Tuners in Series

My radio has an internal antenna tuner that can be activated to rapidly tune for the frequency in use. My antenna has a disgusting SWR for the band I want to use (as measured with an AA-54 antenna ...
4 votes
1 answer
314 views

What dielectric strength is required for a variable capacitors in a 100W T-network antenna tuner?

I would like to build a 100W T-network antenna tuner: I have a 12-pole wafer switch, 12.5 meters of enameled copper wire (d=1.5mm) and a pair of 12-365pF variable capacitors rated 200V DC (dielectric ...
6 votes
2 answers
2k views

Does a tube based HF transmitter need an antenna tuner?

With the adjustments on a transmitter such as a Yaesu FT-101E, is there any purpose for an antenna tuner, or can you accomplish the same thing by adjusting the loading and other controls?
10 votes
2 answers
3k views

What is the actual loss in a feed line with high SWR?

It is well-known that it is unwise to have standing waves on the feed line between one's antenna and one's transmitter, unless it is a very low-loss type (e.g. ladder line), because the transmitted ...
2 votes
2 answers
368 views

Can anyone tell me how to make a 35 m long wire antenna work on 80, 40, 20, 15 and 10 metres?

I have one straight horizontal wire antenna 35 meters (114.83 feet) long. I want to make it work the best on average for the 80, 40, 20 ,15 and 10 meter amateur bands. Can anyone tell me the best ...
3 votes
1 answer
1k views

Benefit to remote antenna tuner for end-fed non-resonant antenna?

Does addition of a remote feed-point antenna tuner affect the use of the coax braid as a radiator? If it no longer "radiates" in such a setup, what does? Is a shack or remote tuner better for ...
2 votes
1 answer
379 views

Does an LDG YT-100 automatically trigger a tuning cycle if the SWR is high?

I have a YT-100 connected to my FT-857d in my remote-by-default shack in the attic (i.e. I operate it over a VNC connection from elsewhere in my house). Whenever I change band I have to go up to the ...