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LDG TW-1
Talking Wattmeter
LDG Electronics
1445 Parran Road, PO Box 48
St. Leonard MD 20685-2903 USA
Phone: 410-586-2177 Fax: 410-
586-8475 ldg@ldgelectronics.com
www.ldgelectronics.com
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LDG TW-1 Talking Wattmeter
Table of Contents
Introduction 2
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 3
Getting to know your TW-1 4
Installation 6
Setup 6
Language 6
Speech mode 6
Volume 7
Speech Operation 8
Tone Operation 8
Application Notes 9
Care and Maintenance 10
Technical Support 10
Warranty and Service 10
Feedback 10
Introduction
Congratulations on selecting the LDG TW-1 talking wattmeter. The TW-1 is a breakthrough
product, providing accurate and precise RF power and SWR readings aurally, by synthesized
voice over a self-contained speaker. It is ideal for situations when you need to watch something
else while making an adjustment, or for visually impaired hams.
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.
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Jumpstart, or “Real hams don’t read manuals!”
Ok, but at least read this one section before you transmit:
1. Attach the RF input jack (right connector when viewed from back) to your transmitter or
transceiver with a 50 ohm coaxial jumper cable.
2. Attach your antenna to the RF output (left connector when viewed from back).
3. Connect a 12 volt power supply capable of delivering 200 ma to the 2.5 x 5.5 mm coaxial
power jack (center positive).
4. While transmitting RF, press and release the left-hand button. The unit will speak the forward
power level. Adjust the volume to the desired level.
5. While transmitting RF, press and release the center button. The unit will speak the reverse
power level.
6. While transmitting RF, press and release the right-hand button. The unit will speak the SWR.
7. The unit will turn itself off after use.
Specifications
• 5 - 2,000 watts, auto-ranging
• +/- 5% accuracy
• 2% power resolution
• Adjustable volume
• Verbose or terse speech
• Tone mode for continuous feedback
• Speaks in English, Spanish or German
• Requires 12 volts at 200 ma, 2.5 x 5.5 mm jack, center positive
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Getting to know your TW-1
Your TW-1 is a quality, precision instrument that will give you many years of outstanding
service; take a few minutes to get to know it. On the front panel, there is a volume knob and three
pushbuttons:
• Volume: adjusts the volume of the synthesized voice
• Forward: measures forward power in watts (Button 1)
• Reverse: measures reverse power in watts (Button 2)
• SWR: measures the standing wave ratio (Button 3)
Power levels are read at 2% resolution. For example, at power levels around 100 watts, the
resolution is 2 watts; that is, the readout will go from "one hundred watts" to "one hundred two
watts" as you increase power. At levels around 1,000 watts, readout will go from "one thousand
watts" to "one thousand twenty" watts.
There is no range switch; the TW-1 auto-ranges from 5 to 2,000 watts. There is no Off switch; the
TW-1 automatically turns itself off after use.
Button 1
Button 2
Button 3
Volume
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On the rear panel, there are two SO-239 RF connectors. The right-hand connector is the RF input
for connection to your radio, and the left-hand connector is the output to your tuner or antenna.
The coaxial DC power connector is on the right.
Antenna
Radio
DC In
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Installation
The TW-1 is intended for indoor use only; it is not water resistant. If you use it outdoors (Field
Day, for example) you must protect it from rain.
Position your TW-1 in a convenient spot on your operating desk, as close to your transceiver or
transmitter as practical. Connect the input jack to your transceiver with a 50 ohm coaxial jumper
(not provided) of suitable power handling capacity. Connect the output to your tuner or antenna.
Your TW-1 requires 12 volts DC at 200 ma. Connect a suitable power supply to the 2.5 x 5.5 mm
coaxial DC input jack using the provided coaxial power connector (center positive).
Caution: High RF voltages may be present on internal components when transmitting. Never
operate your TW-1 with the cover removed.
Setup
Setup options are selected by holding down buttons or combinations of buttons while you apply
DC power. The simplest way to apply power for setup is to unplug, then re-insert the DC power
plug from the back of the TW-1, but you could also turn the DC power supply off then on again.
Setup options are retained indefinitely, even if DC power is removed.
Language
Your TW-1 will speak in English, Spanish or German; the default is English. To set the language,
press and hold a button while connecting DC power:
Button 1: English
Button 2: Spanish
Button 3: German
To reset to a different language, simply remove DC power, press and hold the appropriate button
and reconnect DC power.
Speech mode
Your TW-1 will speak in one of two different modes: Verbose and Terse. In Verbose mode, the
TW-1 speaks in full sentences, as in "The forward power is ninety seven watts". In Terse mode,
only the numerical value is spoken, as in "ninety seven". The default is Verbose mode.
Verbose Mode Terse Mode
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After you become accustomed to your TW-1, you will likely want the shorter readouts, without
all the extra chit-chat. To select "Terse" mode, press buttons 2 and 3 together while you apply DC
power. Thereafter, on pressing a button when RF is present, only the numerical value will be
spoken.
To return to "Verbose" mode, press buttons 1 and 2 together while you apply DC power.
Volume
Simply adjust the volume control to the desired audio level as you use your TW-1
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Speech Operation
Spoken readouts are available on demand; the readout is spoken on button release. There is no
need to set the power range; your TW-1 auto-ranges from 5 - 2,000 watts. With RF present, press
and release a button to produce the following spoken readouts:
Button 1: forward RF power
(Verbose mode example: "The forward power is ninety seven watts")
(Terse mode example: "ninety seven")
Button 2: reverse RF power
(Verbose mode example: "The reverse power is three watts")
(Terse mode example: "three")
Button 3: SWR
(Verbose mode example: "The SWR is two point one")
(Terse mode example: "two point one")
This works best with a constant RF carrier. Using a voice mode (SSB for instance) would require
you to talk and listen at the same time.
Tone Operation
When adjusting a manual tuner or vacuum tube transmitter or amplifier, it is often desirable to
have a continuous readout of power or SWR. Your TW-1 provides this by playing a tone whose
pitch goes up and down with the power or SWR.
To place your TW-1 in Tone mode, simply press and hold any of the three buttons for more than
three seconds before applying RF. The TW-1 will beep to indicate it has changed to Tone mode;
release the button when you hear the beep. When you apply RF, the TW-1 will emit a continuous
tone who's pitch is proportional to the power; the higher the power, the higher the pitch. You can
select either Forward (Button 1) or Reverse (Button 2) power for tone readout.
You can also select SWR for tone readout, as above (Button 3). The pitch of the tone is
proportional to the SWR; the higher the SWR, the higher the tone. If the SWR is above about 5:1,
the tone will pulse to indicate that the SWR is excessive.
After 30 seconds with no RF present, the TW-1 automatically reverts to Speech mode (verbose or
terse, whichever you have set). You can also manually reset it to Speech mode by pressing and
releasing any of the buttons. The TW-1 will beep to indicate that it has returned to Speech mode.
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Application Notes
The TW-1 is primarily intended for visually impaired hams, and those of us more "experienced"
hams who must resort to bifocals, making small meters hard to see at any distance.
The TW-1 is also very useful for special situations when you need to "watch" more than one
meter, as when you are tuning the output stage of a vacuum tube transmitter or amplifier. With
your TW-1 in Tone mode, you can easily watch the plate current meter on the transmitter or
amplifier while listening to the power output on your TW-1 in Tone mode.
The TW-1 is perfectly suited to mobile use. Simply install it in a convenient location near your
operating position, and provide 12 volts DC through a fused line (fuse not included; LDG
recommends a 2 amp fast-blow fuse). SWR Tone mode is especially useful when tuning a
"screwdriver" antenna while watching the road. LDG strongly recommends pulling over to a stop
before adjusting your antenna, but we realize that not everyone does this; you know who you are.
Press and
Release
(RF Present)
Press and
Hold 3 sec
Press and Hold
On Power-Up
Button 1 Forward
Power
Forward Power
Tone Mode English
Button 2 Reverse
Power
Reverse Power
Tone Mode Spanish
Button 3 SWR SWR
Tone Mode German
Button 2+3 _ _ Terse Mode
Button 1+2 _ _ Verbose Mode
Button Summary
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Care and Maintenance
Your TW-1 tuner is essentially maintenance-free; just be sure to observe the power and voltage
limits discussed in this manual. The outer case may be cleaned as needed with a soft cloth slightly
dampened in a mild household cleaning solution. As with any modern electronic device, your
TW-1 can be damaged by temperature extremes, water, impact or static discharge. LDG strongly
recommends that you use a good quality, properly installed lightning arrestor in the antenna lead.
Technical Support
We are happy to help you with your TW-1. Telephone technical support is available at 410-586-
2177 weekdays from 9 am to 5pm Eastern Time. Inquiries by Fax at 410-586-8475 are welcome,
and prompt e-mail support is available at ldg@ldgelectronics.com.
Warranty and Service
Your TW-1 is warranted against defects in parts or workmanship for one year from purchase. The
warranty does not cover damage due to abuse or exceeding specifications. This warranty applies
to the original purchaser only; it is not transferable. A copy of the receipt showing the purchaser’s
name and the date of purchase must accompany units returned for warranty service. All returns
must be shipped to us pre-paid; we will not accept units with postage due. A return form is
provided on our web site for your convenience.
If you need to return your TW-1 to us for service, package it carefully, keeping in mind that we
will re-use your packaging to return the unit to you. A self-addressed return-shipping label, while
not required, will help insure speedy and accurate delivery of your repaired unit. Include a full
description of the problem, along with your name, address and a phone number or e-mail address
where we can reach you with any questions. Repairs average about 3 to 6 weeks.
We will be glad to service your TW-1 after the warranty period has ended. We will notify you of
repair charges by phone or e-mail, and bill you after repairs are completed.
Feedback
If you have an idea to improve our software or hardware, please send us a description. If we
incorporate your idea in the TW-1, we'll send you a free upgrade as a “thank you”.
We encourage everyone who uses the TW-1 to contact us (card, letter or e-mail preferred) telling
us how well it works for you. We are also always looking for photographs of our products in use;
we frequently place such pictures on our Web site (www.ldgelectronics.com).