Comet CAA-500Mk2 User guide

Instruction Manual

Thank you for your purchase of this instrument. It was built under tight quality control

standards and procedures; however, there is always the possibility of damage during

shipping. Should this occur, please notify the dealer from whom you purchased it

immediately so they can initiate the damage claim process with the shipping company.

Please read this manual completely before beginning operation, so as to understand its

features and capabilities fully.

◆

Features

●

Built‐in broadband high‐stability transmitter for easy measurement of resonant frequency, SWR, and impedance.

●

Color LCD & cross‐needle meter display provide SWR and Impedance information simultaneously.

●

Separate ham band segments can be swept to display the SWR characteristics in the graph automatically.

Moreover, it is possible to plot the SWR characteristics manually with user‐defined center frequency and sweep

bandwidth.

●

Size AA alkaline (manganese) or Ni‐MH rechargeable batteries (six required) may be used. Typical battery life is 9

hours of continuous operation when using AA cells.

●

External 8‐16V DC power may be used to power the meter; this allows trickle charging of Ni‐MH cells.

●

The programmable Auto Power Off function preserves battery capacity in case you forget to turn the meter

off.

●

A hand strap post is provided, for ease of use and to minimize the chance of dropping the CA‐500 MarkII.

Important Cautions

◆

This is a delicate measuring instrument; please take care not to drop it or subject it to physical shock.

◆

The impedance bridge of this instrument is immediately inside the antenna connection point. Be absolutely

certain not to apply power from an external transmitter, as this will damage the CAA‐500 MarkII.

◆

Strong local RF fields (in a multi‐station environment, for example) may cause unstable SWR readings.

◆

When not using Ni‐MH batteries, always turn OFF the Charge switch on the battery case. Failure to do so may

result in battery rupture, leakage and/or explosion if you apply charging voltage to alkaline cells.

◆

The external DC supply voltage must be between 8V to 16V, and the current supplied must be at least 250mA.
Never apply DC voltages greater than 16V, nor AC voltage of any kind. Our warranty does not cover damage
caused by the use of an improper power source.

◆

When using AA batteries, the LCD display will become unstable when the batteries are weak. Change Batteries
as soon as the display starts blinking, and change all batteries to improve the battery shelf life.

Remove the batteries when not in use for extended periods of time to avoid damage caused by leakage.

▼

Before using

◆

To avoid ESD damage, it is important to discharge any static electricity that

may have accumulated on the antenna system by touching grounding the

antenna’s coax cable connector before screwing it onto the SWR analyzer.

P.1

◆

Panel/Case Parts and Descriptions

①

Display Meter This Cross Meter displays both SWR and Impedance simultaneously.

②

Multi‐function Display The color LCD (Liquid Crystal Display) shows frequency, amateur band, and SWR data
(impedance (Z)/resistance (R)/reactance (X)), and also can provide a swept‐frequency SWR graph.

③

BAND Knob This knob is used to select the frequency band within the range 1.8 to 500 MHz. Clockwise rotation of
this knob selects a higher frequency band. It is also used for setting of the APO (Automatic Power Off) function.

④

FREQ.Knob This knob is used to set the frequency within the selected amateur band. Clockwise rotation increases
the frequency, while counter‐clockwise rotation lowers the frequency.

⑤

SWEEP/CENTER Button In the “Normal” mode, pressing this button starts an SWR sweep of the band.

・

When in the SWR Graph mode, pressing this button sets the current display frequency to be the center frequency of
the graph. In this mode, rotate the (3)BAND knob to adjust the Sweep width; press the (6) A.P.OFF/WIDTH button to
confirm. Now rotate the (4) FREQ knob to create and display the SWR plot.

⑥

A.P.‐OFF/BANDWIDTH Button In the “Normal” mode, press and hold in this button for three seconds to allow setting
of the Auto Power Off feature’s time interval.・In the “Manual” plot mode, pressing this button allows you to set the
bandwidth of the SWR Sweep.・While in the “Manual” plot mode, pressing this button allows you to change the color
of the SWR Graph.

⑦

GRAPH ON/OFF Button Press this button to switch between the “Normal” mode and the SWR Graph modes.

⑧

POWERButton This is the main Power On/Off button for this device. Press once to turn the unit on, and again to

turn it off.

⑨

RF Connectors These are the coaxial jacks used for connection to the coaxial cable. The left connector is an “M”
(“UHF”) type (used for 1.8‐300 MHz), while the right jack is Type N, used for 300‐500 MHz. Switching is automatic,
based on the Band setting.

⑩

Hand Strap Mounting Bracket You may connect a commercially‐available hand strap here. As the diameter of the

mounting hole is greater than 1 mm, a sturdy strap (highly recommended) may be attached.

⑪

External DC Power Terminal External DC (8‐16V) may be connected here. The center pin is positive (+).

⑫

Battery Case This is the housing for six AA cells. Please install them according to the inscription inside the case.

⑬

Charge Switch (Inside Battery Case) This is the switch for enabling/disabling trickle charging of Ni‐MH cells, if used.

When using Alkaline or similar batteries, be sure to set this switch to the OFF position. In the event of

battery leakage, serious damage to this unit may occur if the switch is set to ON during use.

(※) Trickle charging is useful to help maintain a full charge on your battery by compensating for the slight
self‐discharge that can occur even without a load being placed on the batteries

Before You Start

This instrument has been calibrated with the unit being held horizontally, with the meter facing up. The discussion
below is an operating example; the parameters you set may affect the actual results.

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Always be sure that you connect your coaxial connector to the proper connector. If you are connected to the

opposite connector, measurements will be impossible and if the wrong connector is used, damage to the jack

may occur.

▲

OPERATION

It is helpful to review operation before commencing operation. Steps (1) and (3) may be omitted once you have

verified that the unit is operating properly.

①

Connect a 50‐Ohm dummy load (not supplied) to the “M” (“UHF”) jack.

②

Press the POWER switch to turn the unit on in the Normal mode.

Normal Mode Display Screen

Frequency Battery Status

Band Scale

The amateur bands 1.8‐430 MHz are shown with a blue
band (※1). Red underscore shows current band.
“U”appearstoleftofBatteryiconwhenonUHF.

SWR Scale and Bar

The SWR is displayed graphically and numerically
here. The SWR is shown to two decimal places.

OHMS Scale and Bar

The resistive component of the impedance is shown both
on the bar graph and numerically. Impedance (R, X) is

also displayed numerically. Above 190 MHz, R/X do not appear.

※

1 Note that not all the annotated amateur radio bands are available in all countries.

※

2. If using Nickel‐Metal Hydride batteries, the battery status meter may never show “Full.” You should recharge
the batteries once the Yellow indication appears. If using alkaline cells, replace when the Yellow indicator appears.

③

When connected to a 50‐Ohm dummy load, the SWR indication should be 1.1 or less. If so, the meter is

performing correctly.

④

Perform measurements according to the discussion below.

Battery Level Meter (※2,3)

Full charge CcCharge

Nearly full

Battery low

Battery level

Critically low

▼

SWR Measurement

●

Connect the coaxial cable to the meter; use the shortest possible cable between the antenna and meter, as any
cable between the antenna and meter can transform the measured impedance, and feedline loss can also cause the
displayed SWR to be better than it actually is. See FAQ later.

●

Set the BAND and FREQ knobs to the band and frequency to be tested on the antenna.

●

You may now read the SWR and resistive value of impedance (OHMS) on the display. If there is a subtle

difference between the mechanical and the LCD, the precision of the mechanical meter has priority.

About the Reactance Display

The display of impedance on the LCD includes both resistive (R) and reactance (X) indications. Note that the X
display is absolute value, so the polarity (+ or ‐) cannot be viewed. Because of diminished accuracy, the numerical
R and X displays do not appear above 190 MHz (but the impedance bar graph remains operational).

▼

Measurement of Antenna Resonant Frequency

■

Connect the antenna to the appropriate antenna connector on the meter, using the shortest possible cable. If you
use a long cable, the measurement will also include the effects of feedline loss, and impedance differences between
the antenna system and coaxial cable will not show the actual antenna impedance.

■

While watching the frequency display, rotate the FREQ knob while observing SWR. If you rotate the FREQ knob to
the point where the frequency no longer changes, change the Band to set a new range.

■

The frequency at which the minimum SWR is observed is the resonant frequency for the system.

P.3

Incidentally. . .
Because of stray inductance and capacitance, it is possible for the meter to show a “quasi” reson
ant frequency. If the measured “resonant” frequency is different from what you expected, inspect
your system for these possible issues, in addition to those mentioned previously.

◆

Using the Graph Mode to Display SWR vs. Frequency

There are two types of Graph mode on this meter. You may use a predetermined center frequency and
bandwidth to perform an SWR sweep, and alternately you may set an arbitrary center frequency and bandwidth
to perform a manual SWR sweep.

Auto Sweep Mode

1．While in the Normal display mode, press the SWEEP/CENTER button to initiate
an automatic sweep. The center frequency and sweep bandwidth will be based on
the Band that is currently selected.
2．While the Sweep is in progress, the “SWR” caption will blink. A band Sweep
typically takes about 25 seconds to complete.
3．Once the Sweep is completed, you may repeat the Sweep as many times as
desired by just pressing the SWEEP/CENTER button again.
4．To return to the Normal Mode, press the GRAPH ON/OFF button. Note that the
FREQ and BAND knobs are disabled in the Sweep Mode.

Manual Plot Mode

1．While in the Normal display mode, press the GRAPH ON/OFF button to enter
the Manual Plot mode. A green “SWR” box will appear.

．

The SWR Graph will now be displayed; use the BAND and FREQ knobs to set the

2

desired center frequency for the manual SWR Sweep.

．

Press the SWEEP/CENTER button.

3

The center frequency (rounded to three digits) will appear in the center of the
Graph, and the Sweep Limits (left and right at bottom) will blink.
4．Use the BAND and/or FREQ knobs to set the Sweep bandwidth, then press the

A.P.OFF button to confirm the setting.

・

Because the BAND knob causes huge frequency shift, generally you will use the FREQ

knob to set Sweep Limits.

5．After the setup is finalized, rotate the FREQ knob to perform the Manual Sweep. Gradual rotation of the FREQ knob

allows precision measuring to be performed (minimum resolution 1 kHz).

(“SWR” caption around center of Graph shown in Red

(“SWR” caption around center of Graph shown in Green)

）

Auto Sweep Mode

Manual Plot Mode

6．If you press the AP‐OFF button during a Manual Sweep, the color of the plot will

change (Red ‐>Blue‐> Green ‐>Purple‐>Orange‐>Red...).

7．If you want to change the bandwidth in this mode, press the SWEEEP/CENTER button

again.

8．To return to the Normal mode, press the GRAPH ON/OFF button.

Note: You can not preserve the Graph data if you change Graph Modes

P.4

●

Setting the Auto Power Off Time

■

This procedure sets the Auto Power Off timer, to preserve battery life after meter inactivity.
In the Normal mode, press and hold in the A.P.OFF button for more than three seconds; the currently‐set Auto Power
Off time will be shown on the display (factory default: 5 min.). Rotate the BAND knob to change the timer in
one‐minute increments (0 – 9 min.). When done, press the A.P.OFF button momentarily.

●

If the timer is set to 0 minutes, the Auto Power Off function will be disabled.

●

When power is turned off, this setting will be saved.

Rotate the BAND knob to
change the APO time.

・

Note that the meter will consider frequency change of less than 3% to be “inactivity” when counting down the Auto

Power Off timer.

Quick‐Reference Operation Chart

Power ON

SWR & Resonant Frequency Measurement Mode (Normal Mode)

SWEEP/CENTER Button

Auto Sweep Mode

GRAPH ON/OFF Button

●

Regarding the Charging and Use of Nickel‐Metal Hydride (Ni‐MH) Batteries

・

This meter can be used either with alkaline or Ni‐MH rechargeable batteries.

・

If using Ni‐MH batteries, they may be trickle charged inside the case.

・

TotricklechargeNi‐MH batteries, you must set the small slide switch inside the case (near the battery
holder) to the CHARGE ON position. A small flat screwdriver is ideal for this purpose.

Manual Plot Mode

Set Center Frequency & Bandwidth

Turn FREQ Knob to Plot

GRAPH ON/OFF Button

SWEEP/CENTER Button

Confirm w/A.P. Off Button

GRAPH ON/OFF Button

■

When the battery level indicator changes from yellow to red, apply 12‐14V DC to the DC IN jack to trickle charge the

Ni‐MH batteries. A full charge takes about 14‐15 hours. Wait until the battery indicator shows yellow or red before
charging, to avoid “charge memory” effect.

■

Charging of Ni‐MH cells can be done with as little as 11V DC, but it may take several dozen hours to achieve a full

charge. If the DC voltage is above 14V, the batteries may charge, but their lifetime will be shortened.

・

Trickle charging will occur, regardless of the setting of the meter’s main Power On/Off Switch, if 12‐14V DC is present

at the DC IN jack.

・

The trickle charge current is very low, but we recommend that you turn off and disconnect the DC power source used

for charging if you will be away from the unit for a long time.

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Be certain to turn the charging slide switch to OFF when using alkaline cells!
If you neglect to turn this switch off, and attempt to charge alkaline cells, battery leakage may
occur, which can cause serious damage to this unit (not covered by our Limited Warranty).

Also, do not use a combination of alkaline and Ni‐MH batteries, as damage can occur in case of
an unexpected accident.

●

About Error Messages

If an error occurs during Sweep operation, an error message will appear at the top right. In this
case, ER1 indicates that the frequency of interest could not be set.
Frequently, very strong local RF fields can cause erratic meter operation and/or incorrect SWR
readings.

If ER1 appears even with no antenna connected, there may be an internal malfunction in
the meter. Contact your dealer for repair assistance.

Try to eliminate the strong RF fields and try again.

If ER2 appears immediately aftger powering up the unit, it means
that the internal flash data is corrupted.

Flash Dara Recovery Procedures

1．Press and hold in the GRAPH ON/OFF key; while holding it in, press
thePOWERkeytoturnontheCA‐500 MarkII.

・

Release the GRAPH ON/OFF key when prompted.

・

The version number for the unit’s firmware will; now appear on the LCD.

2. Now press the GRAPH ON/OFF key.
[BAND A] will be displayed.

3．Press the GRAPH ON/OFF key again. [AUTO: 1] will be displayed.

・

Set the FREQ knob to the center of its range.

・

Do not move the FREQ knob hereafter during this procedure.

4．Press the CENTER key. An automatic adjustment process will begin; you will notice a number incrementing

upward.

5．After about two minutes, [COMP: 35 will be displayed. The procedure
is now complete.

6. Now turn the CA‐500 MarkII off.

P.6

FAQ –Frequently Asked Questions‐

Q. When the antenna connected, the resonant frequency appears shifted or there is no SWR dip.

Ans. On an antenna not requiring radials, the case of this unit is the “ground” and it is possible, due to common
mode current flow or other reasons that the meter may be situated in a position that causes radically unusual
readings to occur. Try to relocate the meter as close to the antenna as possible to see if this eliminates the
problem (holding the meter in your hand is often sufficient to suppress common‐mode current).

Q. Even with a known 50‐Ohm impedance, the SWR does not indicate a low value.

Ans. The impedance that you are viewing is an absolute value that also contains a reactance. It is possible to
have the meter show 50 Ohms of impedance without a 1:1 SWR.

Try to get the reactance as close to zero as possible; in this instance, with a total impedance of 50 Ohms and
nearly zero reactance, the SWR will be 1:1 (ideal situation).
In this MkII version, a reactance display has been added. Because it shows the absolute value of reactance (no
“+” or“‐ ”), you cannot initially tell if the reactance is capacitive or inductive. Generally, if the impedance is
capacitive ( ‐ ), then making the antenna shorter (in the case of a dipole or Yagi driven element) will cause the
reactance to increase. If the impedance is inductive ( + ), making the antenna longer will cause the reactance to
increase.

Q. At what point do I want to use a cable for attachment to the antenna?

Ans. To get the most accurate reading of the impedance, the meter should be either immediately at the
feedpoint for the antenna (often impossible) or connected via an integer multiple of a half wavelength of cable at
the frequency being measured. However, feedline loss may affect the results even in this case, so you will not
see the antenna performance alone, but rather the antenna + cable system performance.
When computing a half‐wavelength cable, the velocity factor of the cable must be included. For example, the
velocity factor of RG‐213 type coax is typically 67%. So for 14 MHz this is 492 x 12 (for inches) = 5904 divided by
14 (MHz) x 0.67 = 421.71 inches (including velocity factor).
Depending on the cable diameter and attendant losses, the use of cable lengths in excess of 30m (about 100’)
may yield inaccurate readings, due to the very low power of this unit.

(Before Contacting Us)

Q.Is it possible to connect to the “M” (“UHF) and “N” (Type N) jacks simultaneously?

Ans. Because the jacks are automatically switched, according to the frequency in use, there is no way that both
jacks may be used simultaneously (the opposite connecter cannot be used in case of an incompatibility).

Notes on Handling

●

This unit is fragile: do not drop or subject it to a strong shock.

Physical damage and/or malfunction may occur if unit is dropped.

●

Do not use in very dusty or damp places, or outside in the rain.

This unit is not waterproof nor dustproof, so damage can occur if it is

exposed to spray, rain or severe dust.

●

Please do not disassemble or modify this unit.

To do so may present danger due to electrical shock; product failure or failure to

meet specifications may occur if modified.

●

Please use only at a temperature between 0º and +40º C (+32º to +104º F).

The Liquid Crystal Display (LCD) may malfunction at low temperatures.

P.7

◆

Product Specifications

Frequency Range 1.8 – 500 MHz in 35 range segments

Display Type 1.8 inch TFT Color LCD

RF Output Level 0 dBm (1mW) :HF/VHF , ‐1dBm(0.8mW): UHF

Measured SWR Range Analog Meter: 1.0 – 6.0; LCD:1.0 – 9.9

Impedance Range 12.5 – 300 Ohms (Analog and LCD)

Resistance Range 10 – 500 Ohms
Reactance Range 0 – 500 Ohms (Absolute Value) 1.8‐190 MHz

RF Connectors “M” (“UHF/SO‐239”) for HF/VHF,“N‐female” for UHF

Operating Temp. 0º ‐ 40º C (32º ‐ 104º F)

Power Sources 6 x Alkaline or NiMH Rechargeable Cells

Current Consumption 190 mA or less

Charging Time 15 hours at 12 – 14V DC (trickle charge)

Supplied Accessory External DC Cable (Center pin +/white wire +)

For After‐sale Service

External Power: +8 to +16V DC

Dimensions 3.5(W) x 7.75(H) x 2.65(D)inch (overall)

Weight 2lbs 2 oz (w/alkaline batteries)

●

For questions about this product, contact your dealer or our Technical Support staff

◆

For repairs or in case of shipping damage, consult the dealer from whom this unit was purchased.

■

This unit has a Limited Warranty for a period of one year from the date of purchase by the original purchaser.

Units determined to have manufacturer defects will be repaired or replaced at the discretion of NCG Company.

For warranty inspection, send the unit prepaid to:

NCG Company

Att: Warranty Claims

15036 Sierra Bonita Ln.

Chino, CA 91710‐8901

909‐393‐6133

www.natcommgroup.com

[e-mail]

Specifications for this product are subject to change without notice or obligation,

in the interest of ongoing product improvement.

COMET CO., LTD.

Tsuji 4‐18‐2, Minami‐ku, Saitama‐City, Saitama 336‐0026 JAPAN

TEL: +81 048‐839‐3131 , FAX: +81 048‐839‐3136

URL (Japanese site) : http://www.comet‐ant.co.jp

Copyright (C) 2015 COMET CO, LTD. All Rights Reserved.

1st edition. Sep 2015

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