Manager - NA4M
Manager Notes

Reviews For: LDG KT-100 Autotuner

Category: Antenna Tuners/Matching Networks

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : LDG KT-100 Autotuner
Reviews: 20MSRP: 199.99
The ideal tuner for Kenwood radios. Use the Tune button on the radio to control the KT-100. Matches up to 10 to 1 SWR and up to 125 watts.

Powered by the radio and interfaces to any AT-300 or AT-50 compatible Kenwood radio.
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
WB7VTY Rating: 2018-02-26
Unfortunately Not Impressed with this one Time Owned: 0 to 3 months.
I had high hopes for the KT-100. I use a Z817 with my FT817 and it works great. I have a TS590SG and it works great but I wanted a little better auto tuner performance. I will spare you a description of all my antennas but none of them have wildly high SWRs on any bands. The highest SWR's might approach 4 to 1 but I think there are possibly some problematic complex impedances involved. Just a guess on that. Regardless, my MFJ 949E manual tuner matches it all with ease. I just wanted the convenience of an auto tuner for chasing SOTA contacts all over the bands. The KT is nicely made, no issues there. It DOES tune a couple of antennas in places where the 590SG tuner will give up. It does interface nicely with the 590SG and works with the Tune button on the radio as advertised. The problems are as follows; About 50% of the time it will not achieve a less than 1.5:1 SWR with a normal tuning cycle even when the antenna SWR itself might be around 2:1 or 2.5:1. I have to raise output power to 30 watts and manually force a new tuning cycle and sometimes that doesnt even do it. It NEVER achieves a 1:1 SWR even when the antenna load itself is under 2:1. Occasionally it will get stuck in the "Tune" mode and not release the transmitter. In those cases it requires operator intervention to return to receive mode. The straw that broke the camels back was that on 40 meters, in the middle of a CW contact, it randomly decided to go into the tune mode all by itself and started chattering away while I sent CW. I stopped sending and it stopped tuning, or whatever it was doing. This has to be a case of RF getting into the control system and upsetting it. I tried ferrite beads on the control cable and the problem persisted. So, with that, the MFJ manual tuner went back in and the LDG is out. I gave it a 2 because of the control systems susceptibility to RF and erratic behavior. Its an antenna tuner and should be much more resilient to RF problems. So, on build quality I would give it high marks and if it worked as advertised and achieved SWRs of 1.5 or less consistently I might give it a 3 or 4 for not ever approaching 1:1 even on relatively good loads. However the RF susceptibility and erratic behavior certainly earns it below average marks of some kind. I would like to be able to explain away the issues, but I know one other person who has a 590SG and KT-100 and had similar issues. I wish I could give it better marks but a 2 is as good as I can go on this one. It was a waste of money. No more auto tuners for me. Ive never been enthused about auto tuners so I guess I can at least say that the LDG KT-100 "exceeded" my expectations, and thats NOT a compliment. If you have any questions about it, please feel free to email me at 73
WB4RTP Rating: 2015-05-24
Works great, but needs some work. Time Owned: more than 12 months.
When I first got my KT-100, I connected it to my TS-480SAT in my shack using the supplied control cable and it worked great. But I got the KT-100 to use remotely in my mobile installation, so I extended the control cable, and it didn't work. I double and triple-checked the wiring for correctness and installed RF filters, but it still didn't work in the mobile. I eventually discovered that I had two problems: signal integrity and RFI.
1. Signal integrity: The KT-100 has two control signals plus power and "ground", which is the return for both power and signal. I used CAT-5 cable which has 8 conductors in four twisted pairs. Each pair consists of a solid color insulation and a striped insulation, i.e., green paired with green-white. I connected all of the striped wires to ground. Two of the remaining solid color wires went to power, and the remaining two wires each went to a control signal. This makes sure the twisted wire pairs are properly utilized. I used the diagram in the manual to make sure I had the wires hooked up correctly since the connectors are different at each end. This method gave me proper wire pairing for the control signals which are normal logic levels and can easily be corrupted with ground-loop noise.
2. RFI: Once I had a good control cable, I added a ferrite suppressor to choke RF currents. Specifically, I used an FT-240-31 toroid core, and wound 8 turns of the CAT-5 cable on it. You could use split bead ferrites, but you should install several. I also installed ferrite beads on the input and output RF coax, which amounts to current baluns. This may be overkill, but it works for me. Having to use so much RFI suppression is why I give the KT-100 a 4 instead of a 5.
I use an SG-303 antenna, and the KT-100 tunes it very well on 20-10m, pretty well on 40m, but will only tune on 75m, not 80m.
I have photos of my mobile installation posted in the LDG Yahoo! Group forum if you wish to see it.
W8VKD Rating: 2014-12-21
Seamless on the TSB2000 Time Owned: more than 12 months.
I have this unit hooked to my TSB2000 for 2 years now and I could not be happier. I have a similar unit on my Icom 706mk2G mobile and that's what got me to buy this. The tuner in the TSB2000 would not tune my Imaxx 2000 on 20 meters but the KT-100 does it with no problems. I had to do a bit of research on how to get HRD to connect with the unit but once configured it works great. Quick, quiet and dependable. I'm very happy with my LDG tuners and would not hesitate to recommend them.
KG4RUL Rating: 2014-12-20
Control Cable is Fragile Time Owned: more than 12 months.
The tuner works well but the control cable is fragile. To prevent damage to my cable, I broke out my hot glue gun. A few minutes work and the cable was reinforced.

Earlier 5-star review posted by KG4RUL on 2009-07-05

Got a KT-100 to use with my TS2000(X). It easily matches two of my collection of G5RV variants that are real Bears to tune up even with a good manual tuner! The only tuner that I have that is better is an MFJ Remote tuner which MUCH larger and requires a DC power injector to operate.
NT9M Rating: 2014-12-20
2 year update Time Owned: more than 12 months.
I'm lowering my rating from 5 to 4.

I've used the KT-100 on both a TS 2000 and TS 590 and the tuner works great.

There is one weak link: the cable connecting the KT 100 to the tuner jack on the rigs. Four tiny gauge wires are crimped to pins that push into the plastic connector body. This assembly is very delicate, and last night I managed to accidentally free the wires from the plug body as I was fiddling with some other connections on the back of the 590 while moving on the desk.

I was able to use a fine tip on my soldering iron to solder the tiny wires to the pins while still in the plastic plug body...managing to burn only one finger in the process. It is still a very delicate set-up but at least I'm back in business.

So guys and gals, be careful with that connector assembly! And LDG, please consider providing an assembly that's a little more robust.

KT8R Rating: 2014-12-04
Not bad! Time Owned: 0 to 3 months.
Recently found one of these on Works as advertised and tunes the G5RV when the TS570S failed. Only thing is the rig will not operate the external tuner on 6 meters. Solved the problem by adding an antenna switch between the antenna and tuner. Utilized both connectors on the rig so now can use the internal to tune 6 and the external for 80-10. Works good.
ON5HB Rating: 2014-10-17
Very good and fast tuner. Time Owned: 6 to 12 months.
It's superb, only downside the TS-590S can't let it autotune on 6M, but hey you can program PF-A to do tuner-power-mode and then press the button on the LDG to tune, not the smartest way, but it works.
This is definitely the best tuner I ever had when using 100W or less.
This limitation on 6m is not LDG fault, Kenwood simply doesn't send the tune signal out.
VE6ND Rating: 2014-05-24
Great for mobile Time Owned: 0 to 3 months.
Installed the coupler in my Silverado behind the drivers seat and on the 480sat and it works amazingly well.
With a 108" whip the coupler can tune at whatever frequency I go to and is quite efficient at doing so.
Measured the output and coupling with the Bird Signal Hawk...... Very nice.
Grounding is very important at most frequencies, experimented with no ground and on 15 meters it would tune but would kick low when voice was applied showing the it is a very intelligent coupler.

Overall very pleased with the unit.

Keep up the good work.
N6DXX Rating: 2014-04-09
Outstanding Tuner Time Owned: 3 to 6 months.
I have a 100 ft off center fed dipole. Many tuners I've tried cannot achieve a good match on all bands. This tuner does on all bands from 80 to 10 meters & does it in mere seconds! Most bands come in under 1.2 to 1. On 20 meters it gives me a 1.4 to 1 SWR. I operate the Kenwood TS-50s & am very pleased with the tuner's performance. The fact that it's an auto tuner is just "icing on the cake".

73, Tony, N6DXX
N5TEH Rating: 2013-10-23
Excellent Tuner Time Owned: 6 to 12 months.
I've used the LDG KT-100 with my Kenwood TS-590S for about nine months. I use it to tune a 43 foot Zero-Five Vertical. The KT-100 has been flawless and will tune the 43 footer anywhere from 80 through 10 meters. I'm very satisfied with this tuner and would certainly recommend it to anyone using a Kenwood transceiver.