Antenna Tuners

[Rooster1545]

Hey guys, I have a question about which brand is better or model, I'm currently looking at all sorts of test equipment, thanks for any help.

73's

Waving a hand from Bama

Rooster

[Windwalker]

There are so many tuners out there that I would suggest this.
Get a tuner that will handle the wattage you need.
Cross needle SWR and Power readings.
Some have a Dummy Load allready.
12v DC or 120v AC
The list goes on so I will leave it open for other members to voice their opinion.
3s
WW1

[MDYoungblood]

Not sure by what kind of "Tuner" you are looking for?

3's

Greg

[Gunner357]

Hey guys, I have a question about which brand is better or model, I'm currently looking at all sorts of test equipment, thanks for any help.

73's

Waving a hand from Bama

Rooster

Do you want a TUNER or something like a SWR/WATT meter?

[Rooster1545]

I have an swr/watt meter on mobile and just swr meter on the base, I guess I may overthink things. I just got off base station, trying to talk skip for an hour, with no contact but others in Alabama were being heard, I know I haven't got the power some do and the conditions. So I'm brainstorming I guess

[Gunner357]

well My home made base it 1:1 my mobile is 1:3 I have amp on the mobile 350w the base is just 30 w I cannot get the base to do any skip been trying so you may need some power or a better antenna its a guessing game in a way

[JimboBowie]

Read all about it: [Please login or register to view this link]

[Rooster1545]

I've talked skip on both of mine no amps. I have galaxy dx959 for both setups an A-99 on base and steel whip just behind cab of pickup

[MDYoungblood]

Since you are just talking CB and the antenna is tuned for that band putting an antenna tuner inline will just drop your wattage to the antenna (unless it has a bypass). Most only use tuners for other bands such as ham operators were the antenna is not resident to the frequency they are on, still losing wattage but the radio is happier.

3's

Greg

[Rooster1545]

Ok, thanks MDyoungblood that make sense to me, did you talk tonight?

[MDYoungblood]

I was on the radio mostly all day, channel 39LSB doing on air check-in’s for TWRC, another forum I help moderate like CBRT, made 50+ DX contacts. I do the last Sunday of the month now. Stopped at 8pm and had an informal net on 10m ham band, had a few DX station join in there as well.

3’s

Greg

[De_Wildfire]

If you can get a Autek Research WM1 Computing meeting on the second hand market, go for it. I have had it for years and is very reliable. It has two meters on it and all you have to do is watch it.

[warlock35po]

Hello So called "Antenna Tuners" do not tune your antennas repeat they Do Not tune your antenna.If your antenna is not resonant at the frequency you are using you need to change the length of the antenna, all the "tuner"will do is fool your xcvr into believing it is loading into a resonant load.It will not change any mismatch that may be present and will not allow efficient power radiation.To even know your True S.W.R. you have to start by checking at the antenna.What you see at the xcvr end is subject to the correct length of your coax ie an odd multiple of a half wave taking into account the coax velocity factor

[Bobcat]

Where tuners come in handy is on multi-band antennas. If you build an antenna for, say, 80 m, in THEORY, it should also work at 40 m, 20 m & 10 m..... and multiple harmonic of that lowest band. The theory is good but in practice ... the physical antenna may be close....but not "spot on perfect" on the other bands. A tuner can be used to avoid damaging the transceiver while still allowing you to work on that band.

[warlock35po]

Bobcat.Correct,Regards.warlock35po.

[Double J]

I bought an antenna tuner, I guess just in case, but after reading this forum I hope my new Maco antenna, coax, and radio will have good swr and I won't need to use the matcher.

[Bobcat]

About three weeks ago I went to an "estate sale" and saw an MFJ Deluxe Versa Tuner (MFJ-949E) on the shelf looking awfully lonely. I asked the people running the event what she wanted...... she said $25. (Thing is still on MFJ's site and sells for $219). I am looking at it right now.

[terryj]

If you are trying to fix a mismatch with an antenna tuner, well, it isn't going to work. All you're doing is fooling the transmitter into seeing a matched load, the mismatch still exist between the tuner and the antenna. A tuner works well on a fundamental frequency and all odd harmonics, ie, 7mhz, 21mhz it doesn't work well on 2 harmonics, is 7mhz and 14 mhz, although you can tune your radio with the a 50 ohm load at the tuner a severe mismatch will exist from the tuner to the antenna on an order of 40:1 VSWR. These high VSWR's are going to show up as hotspots on your transmission line. Because 14m is the 2nd harmonic of 7m on a dipole the 14m will present a impedance of around 2000 ohms. this is assuming you're using 50 ohm coax, the way around this issue is to use a "balanced" feed line such ad open wire or ladder line which a good tuner would handle, your transmission loss would be greatly reduced and and antenna system efficiency greatly increased.

[warlock35po]

Hello Terry,Right on Bruddah.

[KOA4705]

[/quote]

If you are trying to fix a mismatch with an antenna tuner, well, it isn't going to work. All you're doing is fooling the transmitter into seeing a matched load, the mismatch still exist between the tuner and the antenna. A tuner works well on a fundamental frequency and all odd harmonics, ie, 7mhz, 21mhz it doesn't work well on 2 harmonics, is 7mhz and 14 mhz, although you can tune your radio with the a 50 ohm load at the tuner a severe mismatch will exist from the tuner to the antenna on an order of 40:1 VSWR. These high VSWR's are going to show up as hotspots on your transmission line. Because 14m is the 2nd harmonic of 7m on a dipole the 14m will present a impedance of around 2000 ohms. this is assuming you're using 50 ohm coax, the way around this issue is to use a "balanced" feed line such ad open wire or ladder line which a good tuner would handle, your transmission loss would be greatly reduced and and antenna system efficiency greatly increased.

As Terryj has stated the antenna tuner at the shack end of a length of transmission will not change the swr on the line. The tuner will transform the impedance at the shack end of the line to 50 ohms with additional losses due to tuner. When you look at manufacturer's specifications for a type of coax. Loss is stated in db vs frequency for a given length of line, typically 100 feet. This is the insertion loss measured when the line is terminated into it's characteristic impedance, swr=1:1 . Photo 1: insertion loss. Conditions: 100 foot length of RG-8U terminated into a 50 ohms load, transmitter output is 100 watts. Power delivered to the load vs frequency(Mhz). Photo 2: Addition line loss due to swr. Conditions: 100 foot length of RG-8U terminated into a 150 ohms load, swr=3:1, transmitter output is 100 watts. Power delivered to the load vs frequency(Mhz). Photo 3: swr vs frequency(Mhz) for 150 ohm load.[Please login or register to view this link]
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[The DB]

I'll just drop this here...

YOUTUBE_ADMIN

YOUTUBE_ADMIN

The DB

[Double J]

Thank you for taking the time to make a video and explain it

[KOA4705]

I'll just drop this here...

YOUTUBE_ADMIN

YOUTUBE_ADMIN

The DB

DB nice! Can you post your setup for measuring S11 and S21 thanks

[The DB]

DB nice! Can you post your setup for measuring S11 and S21 thanks

I have a NanoVNA, which has two SMA ports, one is S11 and one is S21.

On the S11 port, I have a short SMA cable with an adaptor to SO-239 on the far end. That is plugged into the transmitter side of the MFJ-949E. Coax 1 out is a coax that is attached to a dual band 2 meter/70cm dual band magnet mount antenna (and is not removable) which was on a round cookie sheet.

The other port on the NanoVNA, the S21 port, has a similar adapter to a 6 foot piece of coax to a receiving antenna. As I was only looking for a comparison this antenna's size isn't as important, as long as it is enough to get and compare signals. The one currently attached is a 2 meter/70cm j-pole, basically a home made version of the Arrow OSJ 146/440 dual band j-pole antenna.

When running this test, the coax going into the tuner has been calibrated out, as well as the coax going to the second receiving antenna.

I used a marker in the center of the CB band on the NanoVNA when adjusting the tuner for SWR comparisons. Obviously, the lower the better, and for both antennas I was able to get an SWR under 1.2.

I have also done this test on a second antenna, a 2/6 meter dual band antenna, and while I still got some gain, it was not as much as with the 2 meter/70 cm antenna. It was a steady about 1 dB increased gain across the CB spectrum. I'm not sure if it makes a difference but this antenna was about three times as long as the one in the video, and it has its own matching circuit in its base.

I cannot say for certain, at this point, that an antenna tuner on the radio end will always match or increase the amount of radiated power for a given amount of power put into the antenna system. Both times I have tried this, it has, but that does not guarantee that it will happen in every situation. This needs more testing.

If anyone else does a similar test with similar or compatible equipment, I would love to hear about it...


The DB

[KOA4705]

DB nice! Can you post your setup for measuring S11 and S21 thanks

I have a NanoVNA, which has two SMA ports, one is S11 and one is S21.

On the S11 port, I have a short SMA cable with an adaptor to SO-239 on the far end. That is plugged into the transmitter side of the MFJ-949E. Coax 1 out is a coax that is attached to a dual band 2 meter/70cm dual band magnet mount antenna (and is not removable) which was on a round cookie sheet.

The other port on the NanoVNA, the S21 port, has a similar adapter to a 6 foot piece of coax to a receiving antenna. As I was only looking for a comparison this antenna's size isn't as important, as long as it is enough to get and compare signals. The one currently attached is a 2 meter/70cm j-pole, basically a home made version of the Arrow OSJ 146/440 dual band j-pole antenna.

When running this test, the coax going into the tuner has been calibrated out, as well as the coax going to the second receiving antenna.

I used a marker in the center of the CB band on the NanoVNA when adjusting the tuner for SWR comparisons. Obviously, the lower the better, and for both antennas I was able to get an SWR under 1.2.

I have also done this test on a second antenna, a 2/6 meter dual band antenna, and while I still got some gain, it was not as much as with the 2 meter/70 cm antenna. It was a steady about 1 dB increased gain across the CB spectrum. I'm not sure if it makes a difference but this antenna was about three times as long as the one in the video, and it has its own matching circuit in its base.

I cannot say for certain, at this point, that an antenna tuner on the radio end will always match or increase the amount of radiated power for a given amount of power put into the antenna system. Both times I have tried this, it has, but that does not guarantee that it will happen in every situation. This needs more testing.

If anyone else does a similar test with similar or compatible equipment, I would love to hear about it...


The DB

At the end of coax 1 you used a MFJ-949E to match the dual band 2 meter/70cm for 11 meter band?