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RT-100 LDG Remote Auto Tuner

edited February 2017 in Gear Discussion & Reviews

I have a few LDG antenna tuners and this gear review is of the LDG RT-100 which is what I used in a recent configuration for an inverted L antenna for HF work.

Description: The LDG RT-100 is a 100 watt coax in / coax out remote tuner designed to be placed near the feed point of the antenna. If you are worried about power loss due to SWR in your feed line, the RT-100 is the answer. Place the RT-100 near the feed point and the virtually eliminate all feedline loss due to SWR. The RT-100 is DC powered over the coax, so add your own DC injection circuit (bias-T) or use the LDG RC-100 (sold separately) to power and control the tuner from you shack. The RC-100 will provide DC power over the coax as well as control for Auto/Semi mode,


  • Continuous coverage 1.8 to 54 MHz.
  • Power rating: 0.1 to 100 watt power range (SSB and CW), 30 watt digital.
  • 2000 memories
  • Tuning time: 0.1 to 6 seconds full tune, 0.1 seconds memory tune.
  • Tunes 4 to 800 ohm loads (16 to 150 on 6M), 16 to 3200 ohms with optional 4:1 Balun.
  • Power requirements: 12 VDC at 500 mA
  • Enclosure: 6 x 2.5 x 6.5 inches. Weight: 1 pound.


I wanted an auto tuner that I could power remotely and this product was just what I needed. Included with the RT-100 tuner is a remote box called the RC-100 that sends 12v DC down your coax to the tuner. The RC-100 also allows the user to auto tune remotely and bypass the tuner from your antenna as well.

This tuner is ONLY designed to handle 100W. I would not suggest using this tuner for full duty cycle modes like FM or extended RTTY or PSK "broadcasts" unless you keep it under 50W or so.

There is a higher powered version of this same tuner available which has higher powered components.


  • What I like about this tuner is it is simple and easy to use. You TX and the tuner does all the work in finding the best SWR match. In the shack, all you have is one tiny little black box with few switches and lights.

  • What i DO NOT like about this tuner is that you need to transmit into it in order to get a match, so you can not use this tuner for RX only activity. So this may not be for everyone and especially NOT the tuner if you like knobs and buttons!

Remote RC-100 control box (Courtesy of picture at Universal Radio's website):

Actual RT-100 tuner ( Courtesy of Picture on LDG's website:

Here is a crappy little diagram for how I used the RT-100 tuner along with a home made 9:1 balun.

K2GOG LDG RT-100 Gear Review
  1. Would you be interested in seeing more gear reviews?1 vote
    1. Yes!
    2. NO!
    3. Yes and look for my own reviews in the OMARC Forum soon!
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