LDG TW-2 User manual

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LDG TW-2
Talking Wattmeter
For VHF and UHF
LDG Electronics
1445 Parran Road, PO Box 48
St. Leonard MD 20685-2903 USA
Phone: [phone] Fax: 410-
586-8475 [email protected]
www.ldgelectronics.com

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LDG TW-2 Talking Wattmeter
For VHF and UHF
Table of Contents
Introduction 2
Jumpstart, or “Real hams don’t read manuals!” 3
Specifications 3
Getting to know your TW-2 4
Installation 6
Setup 6
Language 6
Speech mode 6
Volume 7
Operation 7
Set Band 7
Voice 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-2 talking wattmeter. The TW-2 is a breakthrough
product, providing accurate and precise VHF/UHF 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. Select desired band; press and hold FWD + SWR for more than 1 second. Repeat until
desired band is spoken.
5. 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.
6. While transmitting RF, press and release the center button. The unit will speak the reverse
power level.
7. While transmitting RF, press and release the right-hand button. The unit will speak the SWR.
8. The unit will turn itself off after use.
Specifications
• Speaks Forward and Reverse power in watts, as well as SWR
• Continuous tone for making amplifier or tuner adjustments
• Power range: 0 – 250 watts PEP
• Accuracy: +/- 5% of reading across entire range
• Resolution: 0.1 watt
• Languages: English, Spanish and German
• Power requirements: 7 – 15 volts DC at 200 mA maximum
• Idle current (not speaking): effectively zero; less than 15 microamps
• Frequency range: 54, 144, 220 and 440 MHz ham bands
• Size: 5” deep x 4.5” wide x 3” high
• Weight: 1 lb.

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Getting to know your TW-2
Your TW-2 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 (FWD Button)
• Reverse: measures reverse power in watts (REV Button)
• SWR: measures the standing wave ratio (SWR Button)
• Band Selection: FWD and SWR buttons pressed together for more than 1 second sets the
frequency band
Readout resolution is 0.1 watt. There is no range switch; the TW-2 auto-ranges from 0 to 250
watts. There is no On/Off switch; the TW-2 automatically powers up when you press a button,
and turns itself off after use.

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On the rear panel, there are two SO-239 RF connectors. The right-hand connector is the RF input
(labeled "Radio") for connection to your radio, and the left-hand connector is the output to your
tuner, amplifier or antenna (labeled "Antenna").
The 2.5 x 5.5 mm jack coaxial DC power connector is on the lower right.

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Installation
The TW-2 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-2 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, and suitable to the frequency range you're
using. Use good quality coax and soldered connectors; avoid crimp-on connecters. Connect the
output to your tuner, amplifier or antenna.
Your TW-2 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 2.5 x 5.5 mm jack coaxial power connector (center
positive).
Caution: High RF voltages may be present on internal components when transmitting. Never
operate your TW-2 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-2, 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-2 will speak in English, Spanish or German; the default is English. To set the language,
press and hold a button while connecting DC power:
FWD Button: English
REV Button: Spanish
SWR Button: 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-2 will speak in one of two different modes: Verbose and Terse. In Verbose mode, the
TW-2 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.
After you become accustomed to your TW-2, you will likely want the shorter readouts, without
all the extra chit-chat. To select "Terse" mode, press the REV and SWR buttons together while
you apply DC power. Thereafter, on pressing a button when RF is present, only the numerical
value will be spoken.

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To return to "Verbose" mode, press the FWD and REV buttons together while you apply DC
power.
Volume
Simply adjust the volume control to the desired audio level as you use your TW-2.
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-2 auto-ranges from 0 - 250 watts.
Set Band
Set the band to the frequency you are using. If you leave it on the wrong band, you will probably
obtain a readout, but it will not be accurate; be sure to set the band correctly. To set the band,
press and hold FWD and SWR together for about a second. When the speaker plays a fluttery
tone, release both buttons; the TW-2 will announce the next band: 54, 144, 220 or 440 MHz. To
check the presently set band, press FWD and SWR together for less than 1 second and release
before the fluttery tone; the TW-2 will speak the present band, but will not change it.
Perform these bandseting key presses with the TW-2 powered up; this is not a "setup" setting that
requires you to apply DC power while holding down the buttons. You can repeat the bandsetting
key presses any time you need to, as often as you need to.
Verbose Mode
"Long"
Terse Mode
"Short"

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Voice Operation
With RF present, press and release a button to produce the following spoken readouts:
FWD Button: forward RF power
(Verbose mode example: "The forward power is ninety seven watts")
(Terse mode example: "ninety seven")
REV Button: reverse RF power
(Verbose mode example: "The reverse power is three watts")
(Terse mode example: "three")
SWR Button: SWR
(Verbose mode example: "The SWR is two point one")
(Terse mode example: "two point one")
Your TW-2 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 tuner, transmitter or amplifier, it is often desirable to have a continuous readout
of power or SWR. Your TW-2 provides this by playing a tone whose pitch goes up and down
with the power or SWR.
To place your TW-2 in Tone mode, simply press and hold any of the three buttons for more than
1 second before applying RF. The TW-2 will play a fluttery beep to indicate it has changed to
Tone mode; release the button when you hear the beep. When you apply RF, the TW-2 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 (FWD Button) or Reverse (REV Button) power for tone
readout.
Band Selection
Hold for 1 second
Repeat until desired frequency
band is spoken

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You can also select SWR for tone readout, as above (SWR Button). 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-2 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-2 will beep to indicate that it has returned to Speech mode.
Application Notes
The TW-2 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-2 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-2 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-2 in Tone mode.
The TW-2 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
remotely controlled 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
FWD Button Forward
Power
Forward Power
Tone Mode English
REV Button Reverse
Power
Reverse Power
Tone Mode Spanish
SWR Button SWR SWR
Tone Mode German
REV + SWR
_
_
Terse Mode
FWD + REV
_
_
Verbose Mode
FWD + SWR Band
No RF needed
_
_
Button Summary

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Care and Maintenance
Your TW-2 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-2 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.
You should never have to remove the cover, but if you do, be sure that no wires are within 2" of
the SWR sensor or the SO-239 connectors when you reassemble the unit.
Technical Support
We are happy to help you with your TW-2. 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 [email protected].
Warranty and Service
Your TW-2 is warranted against defects in parts or workmanship for two years 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-2 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-2 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-2, we'll send you a free upgrade as a “thank you”.
We encourage everyone who uses the TW-2 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).