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Reviews For: MFJ-939 automatic antenna tuner

Category: Antenna Tuners/Matching Networks

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Review Summary For : MFJ-939 automatic antenna tuner
Reviews: 43MSRP: 159.95
Plug & Play! You won’t even know it’s there . . . MFJ-939I/K/Y automatically tunes your antenna as you tune your radio. SWR is just always low.

Tunes your coax fed or random wire antennas 1.8-30 MHz from 2 Watts QRP to full 200 Watts SSB/CW.

Matches 6-1600 Ohms (SWR up to 32:1) -- that’s a 50% wider matching range than competing products that are less capable and higher priced . . . and it’s made in the USA.

Highly intelligent, ultra-fast tuning!
As you’re ragchewing, contesting or DXing, the MFJ-939 is learning your antenna and the way you operate and storing all this in its 20,000 memories. The more you use it, the more it learns.

Measure & Compute = Instant Match
MFJ-939 uniquely measures your antenna’s complex impedance (R, X), computes the L-network and snaps in needed components for instant matching.

AdaptiveSearch determines a sub-set of all solutions that can provide a safe match and searches only that subset giving
you an ultra fast match. Others search slowly through all solutions.

InstantRecall first checks its memory to see if you have operated this frequency before. If so, tuning is instantaneous and you’re ready to go!

MFJ VirtualAntenna Memory
MFJ exclusive VirtualAntenna Memory system gives you 8 antenna memory banks of 2500 memories each.
You can use an antenna switch to select up to 8 antennas and assign each antenna its own 2500 memories!

4 Times More Solutions and Faster!
MFJ has 256 values each of capacitance and inductance for 131,072 matching solutions giving you a finely tuned very low SWR. That`s 4 times the 32,768 solutions of competitors using only 128 L/C values each!
Don`t be fooled by competing products claiming fast search times -- if you have a quarter of the matching solutions, of course,it takes less time to finish but it`s not faster.
MFJ`s faster speed comes from advanced technology and software algorithms not from fewer solutions.Audio SWR Meter
An Audio SWR meter beeps when SWR <1.5, 2, 2.5, 3. Alarms if >3. Audible & Visible Diagnostic messages.

Heavy-Duty Components
Heavy-duty L-network: 10 Amp/1000V relays, RF duty silver mica caps won’t burn up. Safe, reliable, continuous 200W SSB/CW.

As Small as Your Radio
Tiny 6 1/2W x 2 7/8H x 8 3/8D”. 2.4 lbs. SO-39s, random wire ant. & gnd posts.

Never Obsolete . . . Super Versatile
Truly Plug & Play! No settings, only one cable to plug in! Order MFJ-939I, Icom; MFJ-939K, Ken; MFJ-939Y, Yaesu. Specify Yaesu: FT-100/450/950/ 857/897/1000MP/9000/2000 or other.

Never Obsolete!

If you get a new transceiver, simply order a new Plug and Play cable.

Super Versatile! Works with ALL older rigs, classic transmitters, Flex, Elecraft, Tentec, QRP, others. Auto tune antenna -- touch tune button on any MFJ-939I/K/Y for any rig.

2-Year NoMatterWhatWarranty
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
N2XPM Rating: 2015-10-25
Thumbs Up! Time Owned: 0 to 3 months.
When I first got this Tuner and putting it through its paces on a Flat Dipole, I had some band issues not finding resonance. Since changing the dipole to a Inverted V configuration....Wa-La! I am able to work 10-80 meters with no problem. Tuner works quickly. My Dipole is a mini G5RV 46' long fed with 17 feet of Heavy Duty Twin Lead 300ohm to a coax connector and 50' of RG8X. The apex is 30' above the ground. The dipole was purchased from Maple Leaf on Ebay. I was using a Kenwood At-50 Tuner before and it wasn't able to find resonance on 17M's or 60M's. This MFJ Tuner filled the gap and is working past my expectations. I highly Recommend this product!
KB6HRT Rating: 2015-10-01
Works Good! Time Owned: 0 to 3 months.
Have a MFJ 1775 dipole coverage on 40m is narrow, with this little antenna tuner Wonder, can work 7100-7300 a good addition to the shack, will give another review down the road a piece. Can use this small antenna on a smaller lot an get good band coverage, talked all over the place today inside an outside the US with the MFJ 1775. band conditions good on 40-20-17-15 an 10m today.............kb6hrt
KJ4YZI Rating: 2015-06-02
Compact, affordable and FAST! Time Owned: 0 to 3 months.
I Have owned this unit for about 3 weeks, and so far it has me smiling. Tunes my OCF 80 meter dipole 1.1:1 SWR every time. Hundreds of thousands of tuning possiblities with the built in inductors and capacitors, giving it the perfect match. Matches up to 32:1 SWR so even that band that is NON-resonant, it will get you on the air. Very light and compact, so i can use it at field day or a remote operation while traveling. Compatible with every HF radio out there. With the radio interface cable for your rig, you can use the tune feature on your radio such as my FT-450 to automatically set the radio to produce a low carrier to tune. Or just have the tuner inline with your radio, and key up to automagically tune for you. MFJ has always suprised me with their products, and i have been using them for years, if something is not right, they stand behind their warranty. Some others out there do not like MFJ or say they have had many problems. Please do not consider your purchase on just 1 review, shop around, read a lot of reviews, and you will feel good when you made the decision on your own. I Have a video review of this unit on youtube, here is the link
My channel name is Hamradioconcepts. 73 de KJ4YZI