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Reviews Categories | Antenna Tuners | LDG RT-100 Remote Tuner Help

Reviews Summary for LDG RT-100 Remote Tuner
LDG RT-100 Remote Tuner Reviews: 25 Average rating: 3.8/5 MSRP: $199.95
Description: The RT-100 uses the same proven technology as other LDG tuners, but is engineered to be installed outdoors near the antenna feedpoint, reducing potential SWR losses in the transmission line. DC power is provided over the coax; no separate power cable is required. The RT-100 contains an internal “Bias Tee” circuit that separates RF and DC at the tuner
Product is in production.
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W9RTB Rating: 5/5 Jun 10, 2017 19:30 Send this review to a friend
Just As Good As AH-4  Time owned: 0 to 3 months
I have always like to use a remote tuner on my Zero-Five vertical. Before I went off the air for 5 years I used the Icom AH-4 with an IC-7410.
When I got the bug to get back on the air I narrowed down my choice to the LDG RT-100, since I did not want to run an extra cable for control of the tuner.
I use a 28ft Zero-Five vertical along with an UN-UN balun from Balun Design. The turn has no problems tuning from 10-80m. The highest SWR is on 80m about 1.7, but that is to be expected due to the length of my antenna.
The tuning bandwidth is good and required no retuning. I have used it on both the IC-7300 and Yaesu FT-991 and would say it works just as good as the AH-4. Tuning with the control box is easy and almost as quick as the AH-4. To get it to work properly I suggest using the UNUN
W1FYL Rating: 2/5 Jun 7, 2017 07:19 Send this review to a friend
Only Semi-Automatic  Time owned: 3 to 6 months
The manual says it'll remember its settings for previously-tuned frequencies. Mine seems to for 40M at least, but I must force a manual tuning cycle each time I return to 20M, otherwise SWR remains high. This requires changing the transmitter from my usual CW mode to AM or RTTY, then manually transmitting a carrier for some time, since the tuner requires RF to tune. Pretty inconvenient, and hardly automatic.

The manual says that you only need to start transmitting, and the tuner will recall its old settings and adjust; but with CW I don't see any indication that it has tuned, and SWR remains high until I transmit a steady carrier for several seconds.

Unlike some other LDG tuners, this gives no indication that it's tuning or has completed its tuning cycle. The Status Indicator lamp is nothing more than a power-on indicator, and gives no indication of tuning activity. You must watch an external SWR indicator to tell when it's working, or when it has completed tuning.

I've emailed LDG support at least three times to ask for help with these problems, but their emailed replies essentially say, "Gee, that's really strange -- it's not supposed to do that. You must have a problem with 'your system'". Really? That's customer support?

K6GB Rating: 4/5 Jun 3, 2016 16:09 Send this review to a friend
Does the job I needed doing.  Time owned: more than 12 months
I used this particular tuner because it covers 6. I am using it on a TGM mini-beam and it allows me full band coverage and it's small enough to mount on the boom.
KE0EBP Rating: 5/5 Jun 3, 2016 14:06 Send this review to a friend
Does what it is made for but you must understand it's limits  Time owned: 3 to 6 months
One caveat, this is my first autotuner adventure (I do have several manual tuners of different types I use). I bought the RT-100 without the separate LDG ST-100 bias T box thinking I was going to make a simplified very portable all-band QRP station built around my Flex 1500 SDR radio and a laptop. To that end I built a home brew “rig buddy box” the same size as the Flex rig to consolidate other needed auxiliary equipment that included a intermediary 15 volt NiMH battery pack (to keep power lines short and prevent high current voltage drops) along with muti input power connectors to keep it charged, a simple Norcal led SWR indicator (dip the LED to indicate the lowest SWR) to keep track of the remote auto tuning status, and push button bias T power out the coax to feed the RT-100 itself but set up to only remote tune when it was actually needed for changing bands without draining the nattery pack(s) (the latching RT-100 relays were a nice touch there). After I got the buddy box all built and tested I went ahead and hooked it into a home brew 9:1 balum feeding a end-fed wire tuned to 40 meters and let it rip. The tuner has some “undocumented features” (it can lock up and need resetting and just sit there otherwise, and will chatter endlessly if it cant find a tune) but for the most part it tunes the 40, 30, and 20 meter bands within a second or so to about 1.2 to 1.6 SWR and 24, 12 and 10 meter bands to about 1.8 to 2.1 or so. 15 meters seems to be that odd man out and will not tune, but I know the wire is cut a bit too long and it's strung around my small second story condo deck with a inside counterpoise (thanks to HOA rules) so the setup is a bit funky at best. In the 15 meter case the RT-100 just keeps “chattering” away and never resolves the tuning as mentioned and never gets under 3:1 SWR, so I can see why some complain about no real status indicator built into the RT-100 (I use a standard SWR meter to back up my home brew Buddy Box LED SWR indicator for testing). I plan to put a 1:1 coax balum in the system before the RT-100 to keep the stray RF out of it and recut the wire better to see if it will make the remote tuner happier on all bands as well as trying it out on a home brew “Kid” Cobra multi band antenna soon. I'll update this as needed.

In my opinon the LDG RT-100 works pretty much as advertised. As pointed out elsewhere having some kind or remote SWR indication would have been nice, but then that would add complexity and cost to what is in fact a reasonably priced wide range bare-bones simple remote tuner you pretty much leave outside clamped to your antenna mast and forget about after you have done the initial setup to a appropriate muti-band antenna. And if you keep that in mind the RT-100 will not disappoint, and I would certainly recommend it to others under those circumstances. (Tom Mengel, KE0EBP)
W1FYL Rating: 2/5 May 22, 2016 05:46 Send this review to a friend
Disappointing  Time owned: 0 to 3 months
Based on my very previous good experience with the Icom-dedicated LDG IT-100 tuner, I had high expectations for the RT-100, but was disappointed.

My impressions:

-There is no indicator to tell you when the unit is running a tuning cycle, or when the cycle is completed. You must use a separate SWR meter to see what's happening, or you have no way to tell if the tuner is operating at all. The “Status” indicator on the RC-100 Controller is nothing but a steady red power-on indicator lamp, and gives no information about the operating status of the tuner.

-The manual states that simply starting to transmit is all that's needed for the tuner to initiate a tuning cycle. It seems that this is true only with AM, and maybe RTTY or data, but not with CW: this feature seems to work only with a steady carrier. With CW, and I'm guessing that with SSB, too, a tuning cycle may be initiated, but it doesn't seem to be progress to completion unless a carrier is transmitted. When I'm transmitting CW, the unit seems to never complete the tuning cycle: SWR stays high, never dropping to an acceptable level.

Also, what's not said is that the tuning cycle takes a considerable amount of time -- maybe 20 to 30 seconds -- of continuous transmitting, for the cycle to complete. So, you must transmit for a long time under high SWR.

When I first set up the unit, even transmitting a steady AM carrier, the unit would not tune, and I had to manually initiate a full tuning cycle by transmitting a steady carrier and pressing the “Tune” button for two seconds – and then waiting for the cycle to complete.

-If you turn off the controller or lose power, the tuning memory is lost, and the tuner must re-tune on all bands and frequencies. This is really inconvenient, considering the amount of time it takes to tune from scratch.

The RT-100 seems unable to present as low an SWR to the transmitter as can the IT-100 using the same feedline and antenna -- about 1.7:1 at best. With my Icom IC-718, this results in about a 25% reduction in transmitter power output. The tuner seems to produce a rather broad SWR curve across the entire CW segment of each band, so thankfully it's not necessary to re-tune with smallish frequency changes.

-If it weren't for the apparent benefit of having the RT-100 tuning unit remotely located at the antenna feedpoint (reducing standing waves along the [coax] feedline), I'd go back to the old IT-100 tuner, which is very easy to use, fast, and truly automatic – effortless.

-Summary. I'll continue to use the RT-100 for now. But to avoid having to force a tuning cycle each hamming session, I'll leave the power on to preserve the memory. I intend to check the SWR whenever changing bands and before beginning to transmit, since I don't feel confident about the advertised auto-tuning-while-transmitting capability. The unit requires extra steps and monitoring to use, and I would certainly not call it “automatic”.
G4PNF Rating: 5/5 Apr 20, 2016 02:55 Send this review to a friend
Excellent and reliable 2 years on.  Time owned: more than 12 months
I have had the LDG-100 in operation for over 2 years now. I have it mounted externally but protected from the worst of the WX in a plastic box. I have it set up on a random length doublet (about 215 feet) with a random length of 300 ohm ribbon feeder, and a 4:1 current balun before the tuner (and about 100 feet coax from tuner to shack). It tunes all bands from 80m to 6m with a low SWR and will give me a reasonable SWR on top band too. There are a few idiosyncrasies with this tuner which others have mentioned.... like it's tendency to retune sometimes even though a perfect match had been found. It is also a bit slow to find the match when it doesn't have a memory of the frequency or the match has changed (like when it rains sometimes!) but overall I think it is a really solid bit of kit. Once you get used to the way it works you can rely on it to do the job. There doesn't seem to be anything else out there that does the same job as a remote in-line coax in/out tuner and I would certainly get another one if I needed it.
VA3PCJ Rating: 4/5 Aug 26, 2015 11:58 Send this review to a friend
Good multiband (HF & 6m) remote tuner  Time owned: 0 to 3 months
I needed a remote tuner to tune a 43' quasi-vertical wire in HF bands (80m-10m) both with QRP power and QRO up to 100W. The SG-237 Smart tuner failes to tune with QRP power and the Elecraft T1 is rated at a maximum power of 20W. The RT-100 does readily respond to both QRP or QRO RF and, in that respect, it gets the job done. However, I did not give it a top mark because the memory for fast tuning seldom kicks in, and because the best match atatined usually is at an SWR value of 1.7:1, with 17m tuning only at 2.0:1.However, these relative SWR values do not seem to significantly affect the output signal. Overall, a god remote QRP/QRO remote tuner.
K4TB Rating: 4/5 Jul 20, 2015 15:23 Send this review to a friend
It Certainly Helps  Time owned: 3 to 6 months
I've had basically the same experiences with memory tunes as K1ZH described in the previous review, however I do appreciate the fact that the RT-100 matches my antenna on all bands 40-6m, given my circumstances. I am using a 33' Eagle One vertical with no radials, only 3 ground rods. I've used the RT-100 and Eagle One with both my transceivers, an Icom 7600 and a Yaesu FT-897 w/LDG AT-997 Plus tuner, with similar results. After tuning up in a band I can easily move around and find a quick memory match but once I change bands it takes several seconds to find a new match even though I've tuned up there before. Nevertheless it matches nearly everything, bringing the SWR well below 1.5:1 with the worst case about 1.7:1. Interestingly, I can then turn off the RT-100's power and while the tuner retains the last setting, I can turn on the transceiver's own tuner and quickly do a final match down to 1:1. I don't know if the last step stresses the RT-100 but so far no problems. I definitely notice an improvement in received signal strength once everything is tuned, as well as better results when I call stations. Therefore, I consider the RT-100 a useful and effective device. I expect that when I add ground radials for the different bands the RT-100 will be able to work even better.
N4KXO Rating: 5/5 May 15, 2015 13:29 Send this review to a friend
Really works  Time owned: 0 to 3 months
The LDG RT-100 in line with the RC-100 really works. I am using it with my LDG 18 foot vertical at the end of 100 foot run of coax and a 4:1 UNUN. 20 thru 6 meters with no problems. LDG got it right with this product.
K1ZH Rating: 1/5 May 11, 2015 15:58 Send this review to a friend
Same problem as KE2N describes. Memory does'nt work, at all.  Time owned: 3 to 6 months
I have never seen an "instantaneous band" change as their marketing material suggests. I emailed their support - a complete wasted effort. Below is the exchange I had with them.

K1ZH wrote:
I have a question regarding the tuner memories of the RT-100. Do they, in fact, exist? I ask this because since purchasing (9-23-2014) from CheapHam then installing the unit, I have never witnessed an instantaneous tune from memory. Don’t get me wrong, the tuner works to tune the S9V43 on every band just fine, it just never tunes from memory. If I tune the antenna on 20m at say 14.200MHz, I can see the SWR meter start high (e.g., greater than 4), and then fairly quickly fall in steps to below SWR=1.5. The whole process takes about 5 seconds. Then if I switch bands to 40m and tune up at say 7.200MHz, I see similar tuning adjustments by the RT-100. The problem in my mind is that if I switch back to 14.200MHz and tune, I will see the exact same results as when I tuned not 30 seconds earlier - a 5 second search for the L-C combination. Shouldn’t the memory allow, as you state in your marketing material, an “instantaneous band” change? Is my tuner defective?

LDG Support response:
It should be a little quicker than that. However, if the tuner does not think the match was good, it will not store it in memory. Also if it thinks the memory that it recalls is not good, it will do a full tune. It’s most likely not defective.

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