Frequently Asked Questions
Q: Are LDG tuners waterproof?
A: Most are not. Only those specifically intended for outdoor installation such as the RT-100 and RT-600 are water resistant. All others must be kept dry like a typical radio.
Q: Do I need a regulated power supply for my LDG tuner?
A: A regulated linear supply is preferred for best performance. If you have trouble and are using a switching type power supply, try a linear supply to isolate any issues. You can also add RF chokes on the DC power cable to the radio and on the DC power cable to the tuner.
Q: Can I use my LDG tuner with ladder line-fed antenna?
A: LDG tuners are designed for coax-fed antennas. To use it with
an antenna fed with ladder line you need a 4:1 balun. LDG sells a suitable 200W model. Many others are available at Balun-Designs.
Q: Can I use my LDG tuner with a long wire antenna?
A: LDG tuners are designed for coax-fed antennas. To use it with
a long wire antenna you may need a 1:1 balun. LDG sells a suitable 200W PEP model. Higher powered baluns are available from Balun Designs. In any case, a long wire will still need a sufficent ground system that provides a good counterpoise like a ground plane or radials.
Q: What is the dc power connector polarity?
A: The center conductor is positive. The connector size is 5.5x 2.5 mm.
Q: Can I get additional or replacement cables?
Q: Can I remove the circuit board from my LDG tuner ’s case and install it in a home-brew project?
A: Yes, that will work fine as long as you provide adequate RF shielding.
Q: Can I use a M-7600 meter with a different radio?
A: Sorry, no. Each meter is designed to work with a specific tuner. There are very few radios that have a meter port and none of them are compatible with any others.
Q: Can I use a FTL-Meter with a radio other than the FT-897 or FT-857?A: Sorry, no. The meter is designed to work with those specific radios. There are very few other radios that have meter port.
Q: Can I use a IT-100 with a non Icom radio?A: Sorry, no. The tuner is designed to only work with Icom radios that ar AH-4 or AH-3 compatible
Q: Can I use a KT-100 with a non Kenwood radio?A: Sorry, no. The tuner is designed to only work with Kenwood radios that area AT-300 compatible.
Q: Can I use a YT-1200 with a non Yaesu radio?A: Sorry, no. The tuner is designed to only work with Yaesu, FT-450, 950, 1200 and 3000 radios.
Q: How far over the RF power limit can I really operate?
A: Like all well-engineered electronics, LDG products are designed with a reasonable safety margin. However, you should never knowingly exceed the limit specified in the product manual. If a tuner fails under extreme overload it can also damage your transmitter, or even be a fire hazard. Observe the specified power limits at all times.
Q: Do I need to transmit a carrier during a tuning cycle?
A: In most cases, no. LDG
’s advanced tuning algorithms
can tune on the fly as you operate, even on SSB or CW. If you have difficulty tuning in SSB or CW, try AM or FM.
Q: If the tuner is automatic, why are there manual Up and Down controls for C and L?
A: Those controls all you to fine tune the match. You probably won ’t need them very often.
Q: How do I reset all the memories in my tuner?
A: There is no way to reset all the memories at once. They are
overwritten each time you perform a full tuning cycle on the frequency
associated with the memory. So it's the same as a full reset, then reprogrammed with each frequency position as you use the tuner.
Q: My Yaesu tuner won't communicate with the tuner and I get a steady flashing red LED on the tuner.A: Try resetting the radio as described in the radio manual.
Q: My tuner can ’t find a match on 80 or 160 meters on my 43 ’ vertical. What ’s the problem?
A: LDG tuners can match SWR up to 10:1. The SWR on those bands
for that antenna could be much higher. You may need a balun or loading coil.
Q: My tuner matches ok but then re-tunes when I transmit. What ’s wrong?
’s possible that stray RF is getting into
the tuner through the radio interface or DC power cable. Try adding some RF
chokes to the DC cable going to the radio and on the interface cable to the tuner. Suitable chokes are available from
. Also, you could turn the Auto mode off or set the re-tune threshold higher.
Q: My tuner keeps re-tuning as I operate. What ’s going on?
A: The tuner will re-tune any time the SWR exceeds the threshold limit of about 1.7:1.You can place the tuner in Semi mode to keep it from retuning or increase the threshold so it will not retune as often.Try adding some RF chokes to the DC cable going to the radio and on the interface cable to the tuner. Suitable chokes are available from
Q: My tuner works fine on some bands but not on others. How can I fix that?
A: Your coax length may be an odd ¼ wavelength of the frequency that you are trying to tune. Lengthen your coax 3 to 6 feet (1 to 2 meters) on the antenna side right at the tuner. Also try adding some RF chokes to the DC cable going to the radio and on the interface cable to the tuner. Suitable chokes are available from
Q: Can my tuner handle full power on digital modes?
A: No. The power ratings are for PEP SSB or CW. For 100% duty cycle
modes (digital, RTTY, AM) the power limit is about one-third of the power specified. If you wanted to run 100 watts digital, the AT-200ProII would be the better choice.
Q: I have a tuner made for a specific brand of radio (Icom, Kenwood, etc). Can I make it work the same way with other radios?
A: No. Tuners made for specific radios can be used only with the radio it was made for.
Q: The radio interface cable for my brand-specific tuner seems
to fit into the jack on another brand of radio. Will it work with that radio?
Q: My tuner doesn
’t tune when I hold the microphone
button down in SSB or if I'm in CW and press the PTT.
A: The tuner requires RF power to tune. A transmitter in USB or LSB outputs no power when there is no modulation. Some LDG tuners can tune while you
talking on SSB. If that does not work, transmit a constant carrier such as AM or FM. Some radios do not put out any RF power when the PTT is pressed and the mode is CW. They may even show that the TX is on, but no RF power will be transmitted.
Q: My tuner sounds like “marbles in a blender ” when it tunes
A: Yes, it does! Those are the relays switching 30 times per second and do make a bit of noise. This is normal operation. If you hear any relays click during transmit (after tuning) this indicates a possible problem. Reduce power and see if the problem goes away. This can indicate RF in the shack.
Q: Can I connect an SWR/Power meter between the tuner and the antenna?
A: No, that will not work. A meter on the antenna side of the tuner will produce bizarre answers. The meter must be on the radio side of the tuner.
Q: How do you get the tuner out of “bypass ”.
A: Bypass is just the L and C elements in the tuner set to zero. Simply begin a tuning cycle, either memory or full. If the tuner finds that bypass is the best match, it will select that. Alternatively, you could press C-Up or L-Up and the tuner will no longer be in bypass.
Q: My tuner can ’t match my antenna; it stops after about a minute showing infinite SWR.
A: First, some LDG tuners have two antenna ports; be sure you have selected the correct one. Second, LDG tuners can match up to an SWR of 10:1; your antenna may be outside that range.
Q: I hear “arcing ” in my tuner when I transmit on high power. Is that a problem?
A: Yes, that ’s a problem. Be sure to observe the specified power limit of your tuner. Also, RF may be getting into the DC power supply. Try adding RF chokes to the DC power cable leading to the tuner. Suitable chokes are available from
Q: My tuner seems to “lose ” its tune when I transmit on high power. What can I do about it?
A: This sounds like RF interference getting in to the tuner. It could be coming in through the grounds, DC, or coax. Try the tuner with the amp off and see if it still has the issue; it will probably work fine. Also be sure to place the tuner in Semi mode; you don ’ t want the tuner starting while the amp is on. You may be able to reduce RF interference by adding RF chokes on the DC cables going to the tuner and the radio.
Q: Why does the SWR meter in my radio show a higher SWR than the indicator on my LDG tuner?
A: That is normal. The SWR meter in most radios is not very accurate (+/-10%). If it's more than that, the tuner or radio may have an issue.
Q: How do I put my RT-100 tuner in “ bypass ” mode?
A: The RT-100 does not have a “ bypass ” mode. As an alternative method, you could tune the RT-100 to a resonant antenna. That will place the tuner very close to bypass.
Q: At the end of a tuning cycle my tuner is in “ bypass ” . What does this mean?
A: It means that the best match the tuner could find was in bypass. If your antenna is already tuned or close to tuned on the frequency that you are tuning on, setting the Ls and Cs to zero may be the best match.
Q: I have more than one LDG tuner. Some seem slower and louder than others. Why is that?
A: Different models use different relays and other tuning components. Larger relays take longer to switch and de-bounce.
Q: My Yaesu tuner blinks continuously?A: Sometimes, the Yaesu radio will lose the CAT port. You can do a full reset on the radio, then re-enter the tuner parameters to get the CAT port back.
Q: Why can't I tune using my amplifier?
A: The extremely high voltages associated with high power combined with high SWR will arc the relays and destroy them. When the relays are settled, the contacts are rated to handle voltages and current associated with a 2:1 SWR or less to the tuners specified rating by mode.
Parts and Service
Q: How do I return my LDG product for warranty service?
A: Pack the item well. Fill out the return form found on our web
site (under Tech Support) and include it in the package. Ship it to LDG Electronics, 1445 Parran Rd.
St. Leonard, MD 20685. No Return Merchandise Authorization is required, but a complete address and phone number is required. Check the tech-support page for more info.
Q: Will you still fix my LDG product for free after it ’s out of warranty?
’ll be happy to fix it if we can, but not for
free; a reasonable charge for parts, labor and return shipping applies. Return
it to us along with an explanation of the problem. Ship it to LDG Electronics, 1445 Parran Rd.
St. Leonard, MD 20685. No Return Merchandise Authorization is required, but a complete address and phone number is required.Check the tech-support page for more info.
Q: Can I get a copy of the firmware source code?
A: No, the source code is not publicly available at this time. However, many of the products that used a Motorola 68HC11 have the .hex files available on our Yahoo Group. We plan to add more as time permits.
Q: Can I get a copy of the schematic?
A: No, the schematics are not publicly available for the current products at this time. However, many of the schematics for older products are available on out Yahoo Group. We plan to add more as time permits.
Q: Are manuals available in languages other than English?
A: No, the manuals are available only in English. Try using http://translate.google.com/
Q: Where can I order firmware upgrades?
A: Upgrades info for many models are available on our Upgrades page here.