LDG Z-100Plus User guide

Z- 100PLUS OPERATIO

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Table of Contents

Introduction 3
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 4
An Important Word About Power Levels 4
Important Safety Warning 4
Getting to know your Z-100Plus 5

Front Panel 5
Rear Panel 6

Installation 6
Operation 7

Basic Tuning Operation 7
Toggle Bypass Mode: 8
Initiate a Memory Tune Cycle: 9
Force a Full Tune Cycle: 10
Status Indicators 11

Application Information 11

Mobile Operation 11
MARS/CAP Coverage 12
Optional Internal Battery Installation 12
Icom Interfacing 12
Yaesu Interfacing 13

Theory of Operation 13
The LDG Z-100Plus 15
A Word About Tuning Etiquette 16
Care and Maintenance 16
Technical Support 16
Two-Year Transferrable Warranty 16
Out Of Warranty Service 16
Product Feedback 17

PAGE 2

INTRODUCTION

LDG pioneered the automatic, wide-range switched-L tuner in 1995. From its laboratories in
St. Leonard, Maryland, LDG continues to define the state of the art in this field with innovative
automatic tuners and related products for every amateur need.

Congratulations on selecting the Z-100Plus 100-watt automatic tuner. The Z-100Plus provides
semi-automatic antenna tuning across the entire HF spectrum plus 6 meters, at power levels up to
125 watts. It will tune dipoles, verticals, Yagis, or virtually any coax-fed antenna. It will match an
amazing range of antennas and impedances, far greater than some other tuners you may have
considered, including the built-in tuners on many radios.

The Z-100Plus may be optionally powered by internal batteries, eliminating the need for an
additional power cable to use the Z-100Plus. Latching relays are used, so the Z-100Plus consumes
no power when not tuning, so batteries only need to be replaced once per year or less.

JUMPSTART, OR “REAL HAMS DON’T READ MANUALS!”

Ok, but at least read this one section before operating the Z-100Plus:

Turn off power to your radio.
Connect the antenna jack on the transceiver to the “TX” jack on the Z-100Plus, using the supplied

50 ohm coax cable jumper.

Connect a 50 ohm coax antenna feedline to the “ANT” jack on the Z-100Plus.
Power up the transceiver and select the desired operating frequency.
Select AM, FM, CW, or PKT mode, and then key down to transmit a carrier1.
Push and hold the TUNE button on the front of the Z-100Plus for one second (until the Tuning

LED comes on), then release.

Wait for the tuning cycle to end (red LED goes out, 1 - 6 seconds) and then un-key.
Restore the transceiver to the desired operating mode.
You’re ready to transmit!

1

You can tune while transmitting up to 125 watts if your transceiver has a “roll-back” circuit to protect it from high SWR. If it does not

have a roll-back circuit, limit power when tuning to 10 watts.

PAGE 3

SPECIFICATIONS

0.1 to 125 watts SSB, CW, and digital modes.
Latching relays for ultra low power operation.
2,000 memories for instantaneous frequency and band changing.
7 to 18 Volts DC, 100 mA. Virtually zero current when not tuning.
Optionally internal battery powered, 7-18VDC

1.8 to 54.0 MHz continuous frequency coverage. Frequency for memory storage is
determined by internal frequency counter.

Tunes 6 to 800 ohm loads (16 to 150 on 6M), 16 to 3200 ohms with optional 4:1 Balun.
For Dipoles, Verticals, Vees, Beams or any Coax Fed Antenna.
Optional external Balun allows tuning of random length, long wire or ladder line fed

antennas.
Dimensions: 5”L x 5”W x 1.5”H.
Weight: 1.0 pounds
Includes 1 foot Icom and Yaesu 857/897 interface cable and 1 foot coaxial cable jumper.

AN IMPORTANT WORD ABOUT POWER LEVELS

The Z-100Plus is rated at 125 watts maximum power input at most. Many ham transmitters and
transceivers, and virtually all amplifiers, output well over 125 watts. Power levels that significantly
exceed specifications will definitely damage or destroy your Z-100Plus. If your tuner fails during
overload, it could also damage your transmitter or transceiver. Be sure to observe the specified
power limitations.

IMPORTANT SAFETY WARNING

Never install antennas or transmission lines over or near power lines. You can be seriously
injured or killed if any part of the antenna, support or transmission line touches a power
line. Always follow this antenna safety rule: the distance to the nearest power line should be
at least twice the length of the longest antenna, transmission line or support dimension.

PAGE 4

GETTING TO KNOW YOUR Z-100PLUS

Your Z-100Plus is a quality, precision instrument that will give you many years of outstanding
service; take a few minutes to get to know it.

Tuning is performed when the Tune button is pushed on the front of the Z-100Plus and held
for one second. The tuner can be placed in bypass mode by pressing the Tune button momentarily.

Although a DC coax jack is supplied on the rear of the Z-100Plus, the Z-100Plus may also be
powered directly from internal AA or 9V batteries (not supplied); no separate power supply is
needed. The Z-100Plus automatically powers up at the start of a tuning cycle, and goes into an
ultra low-power sleep mode when tuning is complete. The latching relays hold the tuned
configuration indefinitely, even when DC power is completely removed. Tuning memories are
stored in FLASH memory. The internal batteries should last for approximately one year under
normal operating circumstances; longer or shorter depending upon how frequently tuning is
performed.

The Z-100Plus has 2,000 frequency memories. When tuning on or near a previously tuned
frequency, the Z-100Plus uses “Memory Tune” to recall the previous tuning parameters in a
fraction of a second. If no memorized settings are available, the tuner runs a full tuning cycle,
storing the parameters for memory recall on subsequent tuning cycles on that frequency. In this
manner, the Z-100Plus “learns” as it is used, adapting to the bands and frequencies as it goes.

Front Panel

On the front panel there is one pushbutton and two LED indicator lights.

Tune Button: Initiates either a memory tune or a full tune, and also toggles the tuner

between “active” and “bypass” modes.

SWR LED: Lights steady green at the end of a tuning cycle to indicate a good match has

been found.

match is not found.

Tuning LED: Lights during tuning operation, will also blink error codes if a good tuning

PAGE 5

Rear Panel

The rear panel of the Z-100Plus features five connectors.

Antenna connector: Connect the 50-ohm coax antenna feedline to this standard SO-239

connector.

connector to the ANT jack on the back of the transceiver.

GND connector (wing nut): Connect to antenna system ground.
Transmitter connector: Connect the 50-ohm coax jumper cable from this standard SO-239

Power jack: 2.5x5.5mm DC coaxial jack. Connect to 7 to 18VDC, center positive.
Radio Interface jack: Connects via a control cable to a compatible transceiver.

PAGE 6

INSTALLATION

The Z-100Plus tuner is designed for indoor operation only; it is not water resistant. If you use it
outdoors (Field Day, for example), you must protect it from the rain. The Z-100Plus is designed
for use with coax-fed antennas. If use with longwires or ladder-line-fed antennas is desired, an
external balun is required. The LDG RBA-4:1 or RBA-1:1 is ideal, depending on the antenna and
transmission line used.

Always turn your radio off

before plugging or unplugging anything. The radio may be

damaged if cables are connected or disconnected while the power is on.

Connect the HF antenna jack on the transceiver to the Transmitter jack on the back of the Z­100Plus, using the supplied coax jumper cable, or a similar 50 ohm coax cable rated 125 watts or
greater.

The Z-100Plus can interface directly with several popular transceivers. For Icom radios, it will
enable their “Tune” button to start a tuning cycle and provide power to the tuner.

For Icom radios that are AH-3 or AH-4 compatible, connect the white Molex connector into
the radio’s tuner port. The power and radio plugs then connect to the tuner. The tuning process can
start by either pressing the tune button on the tuner or the radio.

For Yaesu FT-897 and 857, use the Y-ACC cable and plug the red end marked “Radio” into
the radio’s ACC port. Connect the black end marked “Tuner” into the tuner’s interface jack. The
radio does not supply power to the tuner. The tune button on the tuner is used for starting the
tuning process.

If you are not using an Icom interface cable for powering the tuner, connect the Z-100Plus to a
source of DC power capable of providing 7 – 18 volts DC at 300 mA, using the provided coaxial
connector (center positive). You can use two standard 9-volt alkaline transistor radio batteries
connected in series (this is very handy for portable operation). If your radio is powered by 12
VDC, you most likely can use the same power supply for the Z-100Plus.

Grounding the Z-100Plus tuner will enhance its performance and safety. LDG recommends
that you connect your tuner to a suitable ground; a common ground rod connected to buried radials
is preferred, but a single ground rod, a cold water pipe, or the screw that holds the cover on an AC
outlet can provide a serviceable ground. LDG strongly recommends the use of a properly installed,
high quality lightning arrestor on all antenna cables.

PAGE 7

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MARS/CAP Coverage

The Z-100Plus provides continuous tuning coverage over its specified range; not just in the

ham bands. This makes it useful for MARS or CAP operation, or any other legal HF operation.

Optional Internal Battery Installation

The Z-100Plus is designed to allow the user to install his own internal battery pack. The
internal battery must be between 7 and 18V DC. A single 9V battery or a 6 or 8-cell AA or AAA
battery holder with batteries installed.

In order to install an internal battery supply, the lid of the Z-100Plus must be removed by first
removing the four screws on the side of the case. Connection of the battery pack to the Z-100Plus
is made via the two battery solder pads at J8 and J9. J8 is the negative terminal, and J9 is the
positive terminal.

Solder a pair of 20AWG or smaller wires to the solder pads at J8 and J9, being careful to
observe the polarity of the connections. The battery pack should be secured to prevent it from
moving around inside the case. For many installations, simply fastening the battery pack to the top
of the relays with double sided tape is sufficient. Care should be taken not to splash solder onto the
circuit board, nor to leave any loose objects inside the case when re-assembling the tuner.

PAGE 11

Icom Interfacing

When interfacing the Z-100Plus with AH-3 and AH-4 compatible Icom radios (IC-706, IC­7000, for example), the Z-100Plus may be operated from the radio’s TUNER/CALL button. Push
the TUNER/CALL button momentarily to toggle the bypass of the Z-100Plus. Push and hold the
TUNER/CALL button for 2 seconds to initiate a memory tuning cycle. Note that the TUNER
button on the Icom IC-756 Pro series transceivers will not activate the Z-100Plus, but pushing
TUNE on the Z-100Plus will still automatically activate the carrier on the IC-756 Pro when using
the Icom interface cable. When using the IC-718, choose AH-4 from the tuner menu.

Yaesu Interfacing

When interfacing the Z-100Plus with an FT-857 or FT-897 using the Y-ACC cable, the Tune
button on the Z-100Plus is used to initiate a tune. The Z-100Plus will automatically key the radio
at the current power level during a tuning cycle and un-key when the tuning cycle is complete.

THEORY OF OPERATION

Some basic ideas about impedance

The theory underlying antennas and transmission lines is fairly complex, and in fact employs a
mathematical notation called “complex numbers” that have “real” and “imaginary” parts. It is
beyond the scope of this manual to present a tutorial on this subject3, but a little background will
help in understanding what the Z-100Plus is doing, and how it does it.

In simple DC circuits, the wire resists current flow, converting some of it into heat. The
relationship between voltage, current, and resistance is described by the elegant and well-known
“Ohm’s Law”, named for Georg Simon Ohm of Germany, who first discovered the principle in

1826. In RF circuits, an analogous but more complicated relationship exists.

RF circuits also resist the flow of electricity. However, the presence of capacitive and inductive
elements causes the voltage to lead or lag the current, respectively. In RF circuits, this resistance to
the flow of electricity is called “impedance”, and can include all three elements: resistive,
capacitive, and inductive.

The output circuit of a transmitter consists of inductors and capacitors, usually in a
series/parallel configuration called a “pi network”. The transmission line can be thought of as a
long string of capacitors and inductors in series/parallel, and the antenna is a kind of resonant

3

For a very complete treatment of this subject, see any edition of the ARRL Handbook for Radio Communications (previously the

Handbook for Radio Amateurs).

PAGE 12

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E 13

process.

No tuner will fix a bad antenna. If the antenna is far from resonance, the inefficiencies inherent
in such operation are inescapable; it’s simple physics. Much of the transmitted power may be
dissipated in the tuner as heat, never reaching the antenna at all. A tuner simply “fools” the
transmitter into behaving as though the antenna is resonant, avoiding any damage that might
otherwise be caused by high reflected power. For best performance, the antenna used should
always be as close to resonance as is practical.

THE LDG Z-100PLUS

In 1995, LDG Electronics pioneered a new type of automatic antenna tuner. The LDG design
uses banks of fixed capacitors and inductors, switched in and out of the circuit by relays under
microprocessor control. An additional relay switches between high and low impedance ranges. A
built-in SWR sensor provides feedback; the microprocessor searches the capacitor and inductor
banks, seeking the lowest possible SWR. The tuner is a “Switched L” network, consisting of series
inductors and parallel capacitors. LDG chose the L network for its minimum number of parts and
its ability to tune unbalanced loads, such as coax-fed dipoles, verticals, Yagis, and, in fact,
virtually any coax-fed antenna.

The series inductors are switched in and out of the circuit, and the parallel capacitors are
switched to ground under microprocessor control. The high/low impedance relay switches the
capacitor bank either to the transmitter side of the inductor bank, or to the antenna side. This
allows the Z-100Plus to handle loads that are either greater than or less than 50 ohms. All relays
are sized to carry 125 watts continuously.

The SWR sensor is a variation of the Bruene circuit. This SWR measuring technique is used in
most dual-meter and direct-reading SWR meters. Slight modifications were made to the circuit to
provide voltages instead of currents for the analog-to-digital converters that provide signals
proportional to the forward and reflected power levels. The single-lead primary through the center
of the sensor transformer provides RF current sampling. Diodes rectify the sample and provide a
DC voltage proportional to RF power. These two voltages are read by the ADCs in the
microprocessor, and are used to compute SWR in real time.

The relays are powered by the 12VDC input provided by the DC coax jack or the optional
internal batteries. The relays are a latching type, and so they consume no current when not
actively switching. Although the microprocessor’s oscillator runs at 8 MHz, which allows the main
tuning routine to execute in only a few milliseconds, the relays require several milliseconds of
settling time for every combination of inductors and capacitors. Thus, it may take several seconds
before all relay combinations are exhausted, in the case of a difficult tune.

The tuning routine uses an algorithm to minimize the number of tuner adjustments. The routine
first de-energizes the high/low impedance relay if necessary, and then individually steps through
the inductors to find a coarse match. With the best inductor selected, the tuner then steps through
the individual capacitors to find the best coarse match. If no match is found, the routine repeats the
coarse tuning with the high/low impedance relay energized. The routine then fine tunes the
inductors and capacitors.

The microprocessor runs a fine tune routine just after the tuner finds a match of 1.5:1 or less.
This fine tune routine now tries to adjust the SWR as low as possible (not just to 1.5); it takes

PAGE 14

about half a second to run.

A WORD ABOUT TUNING ETIQUETTE

Be sure to use a vacant frequency when tuning. With today’s crowded ham bands, this is often
difficult. However, causing interference to other hams should be avoided as much as possible. The
Z-100Plus’s very short tuning cycle, as little as a fraction of a second, minimizes the impact of
tuning transmissions.

CARE AND MAINTENANCE

The Z-100Plus tuner is essentially maintenance-free. Power limits in this manual should be
strictly adhered to. The outer case may be cleaned as needed with a soft cloth slightly dampened
with household cleaning solution. As with any modern electronic device, the Z-100Plus can be
damaged by temperature extremes, water, impact, or static discharge. LDG strongly recommends
the use of a good quality, properly installed lightning arrestor in the antenna lead.

TECHNICAL SUPPORT

The LDG Customer Support Center staff is ready to answer your product question by
telephone and over the Internet. We know that you will enjoy your product even more knowing
LDG is ready to answer your questions as the need arises.

Visit the Support Center at: http://support.ldgelectronics.com

Our website links you to the on-line Customer Support Center where you can send us a
question, do your own research in the LDG Product Knowledge Books, and read through lists of
frequently asked product questions. LDG regularly updates on-line information so the best on-line
support information is available all day and every day.

The LDG website provides links to product manuals, just in case you lose this one! When you
are thinking about the purchase of other LDG products our website also has complete product
specifications and photographs you can use to help make your purchase decision. Don’t forget the
links to all of the quality LDG Dealers also ready to help you make that purchase decision.

TWO-YEAR TRANSFERRABLE WARRANTY

Your product is warranted against manufacturer defects in parts and labor for two full years
from the date of purchase. This two-year warranty is also transferable. When you sell or give away
your LDG product, give the new owner a copy of the original sales receipt and the two-year
warranty transfers to the new owner.

There is no need to complete a warranty card or to register an LDG product. Your product
purchase receipt establishes eligibility for warranty service, so save the receipt. Send a photocopy
of the receipt with the product whenever you send your product to LDG for repair. Products sent to
LDG without a receipt are considered requests for out-of-warranty repair.

LDG does not warranty against product damage or abuse. This means that a product failure, as
determined by LDG, to be caused by the customer or by other natural calamity (e.g. lightning) is
not covered under the two-year warranty. Damage can be caused by failure to heed the product’s
published limitations and specifications or by not following good Amateur practice.

PAGE 15

OUT OF WARRANTY SERVICE

Any time a product fails after the warranty, LDG wants to help you get it fixed. Send the
product to us for repair and we will determine what needs to be done. Based on your prior
instruction, we will either contact you with an estimate or fix it and contact you with a request to
pay any repair charges. Please contact LDG if you have any questions before you send us an out­of-warranty product for repair.

RETURNING YOUR PRODUCT FOR SERVICE

Returning a product to LDG is easy. We do not require a return merchandise authorization.
Visit the Customer Support Center and download the LDG Product Repair Form. On the Repair
Form tell the LDG technicians exactly what happened or didn’t happen and why you believe the
product needs servicing. The technician attempts to duplicate the problem(s) you had based on
how well you describe it so take the time to be accurate and complete.

Ask your shipper for a tracking number or a delivery verification receipt. This way you know
the product arrived safely at LDG. Be sure to give us your email address so our shipper can alert
you online when your product is en-route back to you. We regret that we are not able to provide
periodic updates on the status of repairs. Please be assured that our staff makes every effort to
complete repairs ahead of our published wait time. Your patience is appreciated.

Repairs can take six to eight weeks, but are usually faster than this. The most recent
information on returning products for service is found at the LDG Customer Support Center.

Ship your carefully packaged repair with the Repair Form to:

LDG Electronics, Inc.

Attn: Repair Department

1445 Parran Rd

St. Leonard, MD 20685

PRODUCT FEEDBACK

We encourage product feedback! Tell us what you really think of your LDG product. In a card,
letter, or email (preferred) tell us how you used the product and how well it worked in your
application. Send along a photo, schematic or drawing to illustrate your narrative. We like to share
your comments with our staff, our dealers, and other customers at the LDG website.

http://www.ldgelectronics.com/

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