CommRadio CTX-10 User manual

CommRadio CTX-10 User Manual – Rev E4 - 15 NOV 2018
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USER’s MANUAL
and
Knowledge Base
CommRadio
CTX-10 Amateur Radio Transceiver
AeroStream Communications –CommRadio Division
New Castle, Colorado USA
www.commradio.com
Email: [e-mail]
Copyright © 2018
Commradio div. AeroStream Communicatons All Rights Reserved
No portion of this manual bay be reproduced without permission
of CommRadio / AeroStream Communications

CommRadio CTX-10 User Manual – Rev E4 - 15 NOV 2018
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Revision Status
REVISION
DATE
COMMENTS
PRELIM
05/05/2018
Pre-Release Copy
A1
05/15/2018
Initial Release
B
06/26/2018
Added FAQs, added more Tech Notes
C
07/27/2018
Multiple Updates per revised Firmware
D
07/28/2018
Added ATU information
E4
11/15/2018
[T] switch deactivation, non-iambic keyer, MEM, zero-beat
TX ON_OFF elimination, AGC OFF

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Contents
CommRadio........................................................................................................................ 1
CTX-10 Amateur Radio Transceiver ................................................................................... 1
Revision Status....................................................................................................................... 2
IMPORTANT WARNINGS.................................................................................................. 5
Introduction............................................................................................................................ 7
Firmware, Manual Updates and Social Media....................................................................... 8
Actions, Abbreviations & Symbols Used in this Manual...................................................... 9
Quick Start Guides............................................................................................................... 10
Quick Start Guide - Receiver Setup................................................................................. 10
Quick Start Guide – CW Transceiver Setup .................................................................... 12
Quick Start Guide – SSB Transceiver Setup ................................................................... 14
Quick Start Guide – discussion of Digital Data Modes, directly connected to PC ......... 16
Display ................................................................................................................................. 19
Control Knob [M] ................................................................................................................ 20
Transmitter........................................................................................................................... 21
Keyer................................................................................................................................ 21
PTT AUDIO..................................................................................................................... 22
TUNING MODE ............................................................................................................. 22
Receiver ............................................................................................................................... 23
Filter................................................................................................................................. 23
AGC Speed ...................................................................................................................... 23
SQUELCH ....................................................................................................................... 24
BRIGHTNESS................................................................................................................. 24
STEP TIMING................................................................................................................. 24
TIMEOUT........................................................................................................................ 24
RAPID TUNE.................................................................................................................. 25
Key Pad ................................................................................................................................ 26
Key Pad - BAND ............................................................................................................. 26
Key Pad – MODE (MODE select function) .................................................................... 26
Key Pad – MODE (Morse Code reader function) ........................................................... 26
Key Pad - STEP ............................................................................................................... 26
Key Pad - MEM ............................................................................................................... 27
Key Pad - <LEFT ARROW>........................................................................................... 27

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Key Pad - <RIGHT ARROW> (Tuning resolution function) ......................................... 28
Key Pad - <RIGHT ARROW> (Tuning Knob lock function)......................................... 28
Tuning Knob [T] .................................................................................................................. 28
Rear Panel ............................................................................................................................ 29
Power Input...................................................................................................................... 29
USB.................................................................................................................................. 29
Headphone ....................................................................................................................... 29
SPKR................................................................................................................................ 29
KEY ................................................................................................................................. 30
ACC ................................................................................................................................. 30
MIC .................................................................................................................................. 31
HF .................................................................................................................................... 31
Ground ............................................................................................................................. 31
CTX-10 Technical Notes ..................................................................................................... 32
CTX-10 Power ................................................................................................................. 32
Battery Protection Circuit ................................................................................................ 32
Internal Li-ION Battery Charger ..................................................................................... 32
Monitoring Voltage Input at power jack and Battery Charging ...................................... 33
The Beauty of a COLD BOOT ........................................................................................ 33
Morse Code Reader.......................................................................................................... 33
Beware of interrupting a …Powering Down… Process .................................................. 33
The LOCK function ......................................................................................................... 33
USB Power Bricks for the CTX-10? ............................................................................... 34
Bar Armor for the CTX-10 .............................................................................................. 35
A Peek inside the CTX-10!.............................................................................................. 36
Ambient Noise Gate (ANG) – SSB Audio Processing.................................................... 37
Antenna Tuning Unit – ATU – Some details! ................................................................. 37
CTX-10 Frequently Asked Questions (FAQ) ...................................................................... 38
Q. What was the purpose of the piece of wire wrapped under the Control Knob? ......... 38
Q. The rear of the radio is marked 10 – 20 VDC for power input, but the User’s Guide
says 5 – 20 VDC. Which is it?......................................................................................... 38
Q. When I whisper into the microphone nothing is transmitted. Is my radio broken?.... 38
Q. How should I clean and protect the finish of my radio? ............................................. 38
Q. How do I ‘Zero Beat’ an incoming CW signal that I want to answer?....................... 39
CTX-10 Specifications......................................................................................................... 39

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IMPORTANT WARNINGS
READ THIS MANUAL CAREFULLY to learn all of the features of the CTX-10. Understanding
that you’ll want to use the radio immediately, we’ve included several Quick Start Guides
right up front.
SAVE THIS MANUAL as it contains important safety and operating instructions.
FCC INFORMATION This equipment has been tested and found to comply with the limits
for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed
to provide reasonable protection against harmful interference in a residential installation.
This equipment generates, uses and can radiate radio frequency energy and, if not
installed and used in accordance with the instructions, may cause harmful interference to
radio communications. However, there is no guarantee that interference will not occur in
a particular installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and on, the
user is encouraged to try to correct the interference by one or more of the following
measures:
•Reorient or relocate the receiving antenna.
•Increase the separation between the equipment and receiver.
•Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
•Consult the dealer or an experienced radio/TV technician for help.
CAUTION: Changes or modifications not expressly approved by
AeroStream/CommRadio could void the user's authority to operate this transceiver under
FCC regulations.
WARNING RF EXPOSURE! This device emits Radio Frequency (RF) energy. Extreme
caution should be observed when operating this device. If you have any questions
regarding RF exposure and safety standards please refer to the Federal Communications
Commission Office of Engineering and Technology’s report on Evaluating Compliance with
FCC Guidelines for Human Radio Frequency Electromagnetic Fields (OET Bulletin 85).
WARNING HIGH VOLTAGE! NEVER touch an antenna or internal antenna connector
during transmission. This may result in an electrical shock or burn.
WARNING! NEVER operate the transceiver while driving a vehicle. Safe driving requires
your full attention—anything less may result in an accident.

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NEVER apply more than 20 V DC, such as a 24 V battery, to the power input jack on the
transceiver rear panel. This could cause a fire or damage the transceiver.
NEVER let metal, wire or other objects touch any internal part or connectors on the rear
panel of the transceiver. This may result in an electric shock or could cause a fire or
damage the transceiver.
NEVER expose the transceiver to rain, snow or any liquids.
TEMPERATURE RANGE - It is acceptable to charge and use the CTX-10 in the temperature
range of 0° – 45° C (32° - 113°F). It is acceptable to store the CTX-10 in the temperature
range of -20° to 45° C (-4° - 113°F). Be aware that temperatures on a vehicle’s dashboard
can exceed +80°C (+176°F), resulting in permanent damage to the transceiver if left there
for extended periods.

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Introduction
Thank you for purchasing the CTX-10 amateur radio transceiver. Tracing its
evolutionary roots to the commercial/military/avionics worlds, and borrowing
receiver and design elements from the highly successful CommRadio CR-1 and
CR-1a receivers, the CTX-10 is the latest product from the mind of Don Moore,
N0HDX.
The CTX-10 was designed to be rugged and user-friendly with a minimum number
of user interface interactions to produce the desired system functional change.
Standard equipment user replaceable internal Lithium Ion batteries provide power
for a day’s casual operation. The ability to provide operational power and
simultaneously recharge the batteries from most any 5 to 20 VDC source provides
low-cost portable expansion capability and unlimited field operation. Standard
equipment internal wide-range Automatic Antenna Tuner, CW Keyer and CW
Reader provide everything you need for full functionality in one lightweight, die-
cast aluminum package with no need for supplementary cooling solutions during
high duty cycle operations.
It is the purpose of this manual to provide you with one source for basic through
advanced operations, trouble-shooting, fielding notes and FAQs. This manual will
be maintained as an up-to-date online PDF document, suitable for printing or
viewing on most any electronic device. Be sure to always check the FAQs from
each new revision for the latest and greatest information!
Manual written by Bob Martin, WB2KTG.
Comments and questions regarding the manual or the CTX-10 in general may be
addressed to me at: com[email protected]

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Firmware, Manual Updates and Social Media
Contact [email protected] or register online at www.commradio.com to
register your warranty and to automatically receive automated email notices when
updates to firmware or this manual are available. The most recent version of this
manual, system firmware, additional support information and related topics of
interest can always be found on our website: www.commradio.com
The direct dropbox link for the latest user’s manual and system firmware and
firmware update instructions is:
https://www.dropbox.com/sh/o52isgpavqz2org/AACRWiWTE5wNPN9pwO_PeMK
Ya?dl=0
If you’re a friend of social media, CommRadio is on Facebook and Yahoo! Groups,
as well as RadioReference.com.

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Actions, Abbreviations & Symbols Used in this Manual
[AGC] Automatic Gain Control – automatically adjusts RF gain
[ANG] Ambient Noise Gate – automatic SSB audio processing
[ATU] Antenna Tuning Unit – matches CTX-10 to antenna
[BAND] The [BAND] key on the keypad
Click Rotate the Control Knob [M] one detent {CW} or {CCW}
CW Continuous Wave, as in Morse Code
{CW}Clockwise rotation of a knob
{CCW} Counter Clockwise rotation of a knob
<LEFT ARROW> The lower left button on the key pad
LOCK A function of the <RIGHT ARROW> button to LOCK controls
[M] Control Knob, or Menu Knob, the left knob on the front
panel
[MEM] The [MEM] key on the keypad
[MODE] The [MODE] key on the keypad
PUSH Quickly push in and release (holding for less than ½ second)
<RIGHT ARROW> The lower right button on the key pad
[RX] Receive, Receiver
[STEP] The [STEP] key on the keypad
[T] Tuning Knob, the right knob on the front panel
[TX] Transmit, Transmitter
UNLOCK Opposite of LOCK Returns radio to normal operations

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Quick Start Guides
Quick Start Guide - Receiver Setup
Connect a suitable 5 – 20 VDC power source to the Power Input jack on the rear panel
using a standard 5mm barrel, 2.5mm pin plug. An external power source is not necessary
if the internal batteries have sufficient charge. See below for determining battery charge
status.
Connect an antenna cable to the BNC HF jack on the rear panel. The use of a suitable SO-
239 Female to BNC Male adapter may be required to connect from an existing antenna
cable to the CTX-10’s BNC connector. These adapters are available in right angle as well as
straight configurations as illustrated below.
Press Control Knob [M] in for two seconds and release. You will see INITIALIZING, the
WELCOME! Screen, then the standard frequency display screen.

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Looking at the display, you see a small battery shaped icon and a number in the lower
right corner. The battery will appear all filled-in when it is holding 100% charge. The
amount of fill-in is a quick indication of the amount of charge. In addition, two digits are
shown to the right of the battery. Those digits give an approximate indication of the
charge status, where 90 represents 90%, 80 represents 80%, etc. NOTE: Battery 100%
charge just shows icon, no numbers. NOTE: When battery charge is less than 20%, battery
icon shows an “X”.
Turn Control Knob [M] {CW} until a suitable audio volume level is heard. Select
desired mode by pressing keypad button MODE repeatedly. Select the desired
amateur band by pressing the keypad button BAND repeatedly. For non-amateur band
reception, select the nearest amateur band and tune up or down selecting an appropriate
tuning step size.
The selected tuning step size is shown by the highlighted digit on the display. To change
the selected tuning step size press the <LEFT ARROW> or <RIGHT ARROW> to move the
selected digit Left or Right. Tuning step sizes of 1MHz, 100, 10, 1 kHz, 100, 10 Hz may be
selected.
Turn Tuning Knob [T] to select the desired frequency.
Enjoy!
To turn OFF, Press Control Knob [M] in for two seconds and release.
If, for some reason the radio does not turn OFF, press and hold Control Knob [M] for six
seconds and the radio will turn off.

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Quick Start Guide – CW Transceiver Setup
Connect a suitable 5 – 20 VDC power source to the Power Input jack on the rear panel
using a standard 5mm barrel, 2.5mm pin plug. An external power source is not necessary
if the internal batteries have sufficient charge. See below for determining battery charge
status.
Connect an antenna cable to the BNC HF jack on the rear panel. The use of a suitable SO-
239 Female to BNC Male adapter may be required to connect from an existing antenna
cable to the CTX-10’s BNC connector. These adapters are available in right angle as well as
straight configurations as illustrated below.
Press Control Knob [M] in for two seconds and release. You will see INITIALIZING, the
WELCOME! Screen, then the standard frequency display screen.

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Looking at the display, you see a small battery shaped icon in the lower right corner. The
battery will appear all filled-in when it is holding 100% charge. The amount of fill-in is a
quick indication of the amount of charge. In addition, two digits are shown to the right of
the battery. Those digits give an approximate indication of the charge status, where 90
represents 90%, 80 represents 80%, etc. NOTE: Battery 100% charge just shows icon, no
numbers. NOTE: When battery charge is less than 20%, battery icon shows an “X”.
Turn Control Knob [M] {CW} until a suitable audio volume level is heard. Select desired
mode by pressing keypad button MODE repeatedly. Select the desired amateur band by
pressing the keypad button BAND repeatedly. For non-amateur band reception, select the
nearest amateur band and tune up or down selecting an appropriate tuning step size.
The selected tuning step size is shown by the highlighted digit on the display. To change
the selected tuning step size press the <LEFT ARROW> or <RIGHT ARROW> to move the
selected digit Left or Right. Tuning step sizes of 1MHz, 100, 10, 1 kHz, 100, 10 Hz may be
selected.
Turn Tuning Knob [T] to select the desired frequency.
Connect either straight key or paddles to key jack. For use with an EXTERNAL keyer,
configure CTX-10 as Straight Key – turn the internal keyer OFF.
Push [M] momentarily to enter Menu Selection Mode, then rotate [M] one click {CW} to
enter TX_POWER mode. Push [M] to select current Power. Rotate [M]
{CW} or {CCW} to select 1W, 5W or 10W. Push [M] to select the displayed status.
Enjoy using your CTX-10!
To turn OFF, Press Control Knob [M] in for two seconds and release.
If, for some reason, the radio does not turn OFF, press and hold Control Knob [M] for six
seconds and the radio will turn off.

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Quick Start Guide – SSB Transceiver Setup
Connect a suitable 5 – 20 VDC power source to the Power Input jack on the rear panel
using a standard 5mm barrel, 2.5mm pin plug. An external power source is not necessary
if the internal batteries have sufficient charge. See below for determining battery charge
status.
Connect an antenna cable to the BNC HF jack on the rear panel. The use of a suitable SO-
239 Female to BNC Male adapter may be required to connect from an existing antenna
cable to the CTX-10’s BNC connector. These adapters are available in right angle as well as
straight configurations as illustrated below.
Press Control Knob [M] in for two seconds and release. You will see INITIALIZING, the
WELCOME! Screen, then the standard frequency display screen.
Connect compatible microphone to RJ-45 style MIC jack on rear panel. One suggested
microphone is the Yaesu MH-31 A8J.

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Push [M] momentarily to enter Menu Selection Mode, then rotate [M] one click {CW} to
enter TX_POWER mode. Push [M] to select current Power. Rotate [M]
{CW} or {CCW} to select 1W, 5W or 10W. Push [M] to select the displayed status.
Push [M] momentarily to enter Menu Selection Mode, then rotate [M] three clicks {CW} to
enter PTT AUDIO mode. If required, rotate [M] to cycle to ON. Push [M] to select current PTT AUDIO
mode. PTT ON enables pin 1 of ACC jack, and allows setting of audio level.
Enjoy using your CTX-10!
To turn OFF, Press Control Knob [M] in for two seconds and release.
If, for some reason, the radio does not turn OFF, press and hold Control Knob [M] for six
seconds and the radio will turn off.

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Quick Start Guide – discussion of Digital Data Modes, directly connected to PC
The CTX-10 has been tested using the most popular WSJT-X FT8 data mode. As of June
2018, the starting point for WSJT (Weak Signal Joe Taylor) information is:
https://physics.princeton.edu/pulsar/k1jt/
Refer to the WSJT-X User Guide (all modes) and the FT8 Operating Guide. Mode FT8 was
launched in mid-2017 and rapidly became the most popular mode on HF. It uses
sequential 15 second windows to alternately receive and transmit, requiring accurately
synchronized clocks amongst all stations. This is most easily accomplished by configuring
your PC to automatically update system time using an Internet based time standard.
WSJT-X is user friendly and the interface to the CTX-10 is straight forward, requiring no
third party interfacing hardware.
This mode has a 50% duty-cycle, transmitting 50% of the time, receiving 50% of the time.
Since the CTX-10 is designed to be capable of 100% duty cycle, 50% is very easy duty with
no internal or external fan required. The die cast aluminum CTX-10 enclosure is the
heatsink for all power circuitry, providing excellent convection cooling to the ambient air.
Program Installation: WSJT-X is freeware and is installed on a PC. Use your browser to
search “WSJT-X Download” to locate.
Connections: The only connections are conventional sound card audio (headset and Mic
jacks) lines. No interface electronic box of any kind is required, (e.g. no Signalink USB ™)
1. Connect sound-out (received audio data from CTX-10) from either the headset jack
or pin 5 of the Accessory jack (suggestion: use a commonly available Male-Male 6-
pin mini-DIN cable, cut in half to give you two interconnect cables).
2. Connect sound-in (from PC-transmitted data) to pin 1 of the Accessory jack.
3. PTT is available on pin 3 of the Accessory Jack if your PC has a serial port.
However, this is unnecessary! The CTX-10 includes an ‘Audio – VOX’ that is
activated and set by the user. Data modes use continuous audio during the entire
transmission and the CTX-10 will turn-on the transmitter when audio is switched
on the WSJT-X GUI.
4. See this User’s Guide, section Rear Panel – ACC for the pin-out of the 6-pin mini-
DIN connector.
5. Many new laptops do not have the legacy 3.5 mm stereo headset and microphone
jacks. However, some third party laptop docking hubs (for USB 3.0, audio,
monitors, Ethernet) do provide these. An example is the Wavlink Universal USB

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3.0 Docking Station that includes these legacy jacks. Another option is to use a
readily available USB audio dongle, example shown below.
Audio Levels: (One time settings):
1. Audio-out to sound card (received data): Use the audio level control on the left
side of the WSJT-X GUI and set into the ‘green’ on the level bar.
2. Audio-in from sound card (transmitted data). CTX-10 [MODE] must be set to
either USB or LSB (not AM or CW) for the audio level to show on the PTT_AUDIO
screen. The audio level will need careful adjustment. The audio level must be high
enough for full power. However, if set too high, the transmitter will over-
modulate and cause interference. The WSJT-X GUI has a level setting bar on the
right side. Note: The CTX-10 will not transmit when on the PTT_AUDIO screen
while using the WSJT ‘TUNE’ button.
a. Start with setting your sound-card audio level at approx. 35 % to 40 %.
b. On the CTX-10, select the ‘PTT AUDIO’ Menu. Select ON (to enable). NOTE:
when on this screen the screen will not ‘time-out’ and will not allow
transmitting, thus enabling the user to use the TEST button on WSJT-FT8 to
adjust the level without transmitting. To exit – push twice or rotate [T]
Tuning Knob one click.
c. Start the audio source (WSJT-X test signal) and advance the WSJT-X Power
level until the CTX-10 screen reads 100 to 130. (That corresponds is 100 to
135 mVrms audio level).
d. Preferred method is to use a dummy load to do this testing to avoid on-
the-air interference. If you must test on-the-air, tune to an open (non data-
mode) CW frequency and properly identify yourself. The established data-
mode frequencies are very busy especially during band openings. Your

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fellow operators will appreciate your consideration and courtesy. As a
reminder, The CTX-10 will not transmit when on the PTT_AUDIO screen
while using the WSJT ‘TUNE’ button.
Frequency Control: WSJT-X can control the frequency of many brands of transceivers.
However, at this time, this feature is not supported on the CTX-10. Simply tune your CTX-
10 to the typical frequencies shown on the WSJT GUI. These frequencies may be stored
in the CTX-10’s memory for easy re-use. Please refer to Key Pad - MEM in this User’s
Manual for details. CommRadio will provide frequency-band changes over USB in the
future (your hardware is compatible). Note: Native USB data mode will not be supported
by the CTX-10, only data via standard soundcard interface.
Operating: The CTX-10 is now a slave to the WSJT-X GUI (except for frequency changes).
Follow the WSJT-X user guides. You can operate (using GUI displayed on PC) with a series
of mouse clicks to answer establish contact by calling or answering a CQ, provide location
and an automatic signal report, send 73, and then auto-log your contact.

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Display
The display is a low power, 64 x 128 pixel, 1.5” diagonal amber Organic Light Emitting
Diode (OLED) component. The glass screen is Electromagnetic Interference (EMI) shielded.
This adjustable intensity display was selected for it’s extremely lower power consumption
and easy viewing indoors in dark environments as well as outdoors under varying ambient
lighting conditions. It is not intended for viewing under direct sun. The display uses very
little power regardless of intensity setting. Set to your personal comfortable intensity.
Above is an example of the display during normal receive conditions. The band selected is
the Amateur 20 Meter band. The mode is CW. The signal strength on the digital ‘S’ meter
is S2. The battery status is 80% charged. The audio filter bandwidth is 2.2 kHz. The display
you see will probably be different based on your selection of operational parameters but
the locations of the data will remain the same. Note: 100% Battery Status shows only a
solid battery icon. No numeric display will show for 100% charged battery.

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Control Knob [M]
Description: Rotary Encoder, 12 detents per revolution with push-in switch. Selection will
automatically time-out for all selections except PTT Audio.
ON/OFF Control
Push and Hold [M] two seconds to turn - ON
The two numbers at the bottom of the WELCOME! screen display are the software revision (left) and
the radio’s electronic serial number. The software revision will change if the software in the radio is
revised. The electronic serial number is permanent for each radio, and is also shown on a label on the
CTX-10’s bottom cover.
Push and Hold [M] two seconds to turn - OFF
Volume Control
Simple rotation of the Control Knob [M] raises or lowers the headset and speaker volume.
NOTE: Separate audio levels are maintained for speaker and headphone jack.
There is no indication of the volume level on the display.
Menu
With power on, Push [M] momentarily to enter Menu Selection Mode. If you wait too long without
action, the display will revert to Display Frequency mode.
The default, first Menu entry visible is the Antenna Tuning Unit (ATU).
Push [M] to TUNE. The ATU screen displays PUSH TO END until the ATU has finished tuning for the
attached antenna, or until [M] is pushed again, ENDing the tuning process. When OUT-OF-BAND is
displayed, the selected frequency is outside the legal US amateur bands. Transmit and Tune functions
are not allowed outside the legal US amateur bands.