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UHF Whip Antenna 5/8, 5

dB

, NMO

JAVAD GNSS

www.javad.com

Rev.1.5 June 26, 2017

Specifications are subject to change without notice

 

Electrical Specifications:

Frequency 

406-430 (p/n 99-587303-01)
430-450 (p/n 99-587304-01)
450-470 (p/n 99-587305-01)
450-455 (p/n 99-587305-20) 
455-460 (p/n 99-587305-30) 
460-465 (p/n 99-587305-40) 
465-470 (p/n 99-587305-50) 

Gain

5 dBd (7.15 dBi)

VSWR*

< 1.5:1

Impedance

50 Ohms

Radiation Pattern 

Omni directional

Power Rating

200 W

Mechanical Specifications:

Radiator 

Stainless steel

Matching coil

Silver plated enclosed coil

Base

ABS, chrome plated brass

Length

39" maximum

Weight 

0.51 lbs (0.23 kg)

Mounting 

NMO type

COMTELCO

Technical Specification

A1845A,B A1845AS,BS

________________________________________________________________

406-512 MHz 5dB Gain

BASE LOADED MOBILE ANTENNA

High Performance:

A full 5dB gain is achieved in this

premium antenna by featuring a 5/8 wave over 5/8 wave

whip with a base loaded matching coil. It has a power

handling capacity of 200 watts.

Stylish and Durable:

This antenna is manufactured

using the finest corrosion resistant materials and finishes

available. The base is triple plated chrome brass with an

insert molded low loss coil form and a spring loaded

contact. The silver plated phasing coil is fully enclosed to

insure years of dependable service. It is available in both

brite and black finish.

Weatherproof:

O ring seals and overlap construction

keep moisture out of the antenna.

Economical:

These base loaded antennas feature a

great price to performance ratio.

Standard Mounting:

All Comtelco base loaded

antennas mate with the standard TAD/NMO type mount.

ELECTRICAL SPECIFICATIONS:

FREQUENCY RANGE:

406-512MHz

GAIN:

5dB

IMPEDANCE:

50 ohms

POWER RATING

:

200 watts

VSWR:

<1.5:1

RADIATION PATTERN:

Omni directional

MECHANICAL SPECIFICATIONS:

RADIATOR:

Stainless steel

MATCHING COIL:

Silver plated enclosed coil

BASE:

ABS, chrome plated brass

CONTACT:

Spring loaded contact

LENGTH:

39" maximum

WEIGHT:

< 1 lb.

MOUNTING:

Standard TAD/NMO type

Ordering Information:

FREQUENCY

BRITE

BLACK

406-430MHz

A1845A-06

A1845B-06

430-450MHz

A1845A-30

A1845B-30

450-470MHz

A1845A-50

A1845B-50

470-490MHz

A1845A-70

A1845B-70

490-512MHz

A1845A-90

A1845B-90

To order with shock spring add suffix S to the part

number.

Example:

A1845AS-50 or A1845BS-50

Vertical Pattern

90

60

30

0

330

300

270

240

210

180

150

120

406-430 MHz

430-450 MHz

450-470 MHz

Frequency, 

MHz

CUT WHIP

Frequency, 

MHz

CUT WHIP

Frequency, 

MHz

CUT WHIP

inches

cm

inches

cm

inches

cm

405.0

13 7/16

34.2

430.0

12 5/16

31.3

450.0

11 5/8

29.5

406.0

13 1/4

33.7

432.5

11 15/16

30.3

452.5

11 3/8

28.9

410.0

12 5/8

32.0

435.0

11 1/2

29.3

455.0

11 3/16

28.4

412.5

12 1/2

31.7

437.5

11 1/8

28.3

457.5

10 15/16

27.8

415.0

12 3/16

31.0

440.0

10 11/16

27.2

460.0

10 3/4

27.3

417.5

11 15/16

30.4

442.5

10 7/16

26.5

462.5

10 9/16

26.8

420.0

11 5/8

29.6

445.0

10 1/8

25.8

465.0

10 5/16

26.2

422.5

11 1/2

29.2

447.5

9 15/16

25.2

467.5

10 1/8

25.7

425.0

11 3/16

28.5

450.0

9 5/8

24.5

470.0

9 7/8

25.1

427.5

10 9/16

26.9

430.0

10 7/16

26.6

WHIP CUTTING INSTRUCTIONS

The whip should be cut to the length that corresponds to the de-
sired frequency you expect to operate on. In most cases it is de-
sired to cut the whip a bit longer than the chart and make final ad-
justment by moving the whip in the adapter. Please note that the 
lengths given in the chart are the total length of the antenna whip.
Each antenna is supplied with a whip that is trimmed to operate 
at the lowest frequency. To adjust for a higher frequency you must 
cut an appropriate amount from the bottom of the whip. Adjust-
ment of the exact frequency can be made by moving the cut whip 
up or down in the adapter and checking the lowest VSWR.
Coil assemblies are factory tuned and sealed. No adjustment should be attempted on them. All frequency adjustments 
should be made by trimming the whip. As a rule, you should be able to obtain a VSWR of 1.5 to 1. If you are unable to 
accomplish this, a check for correct whip length and proper mounting condition is recommended.

1) Using hexagon wrench unscrew two screws at the base 

of the antenna and remove the antenna whip.
2) Cut the end opposite the antenna’s top in accordance 

with the table.
3) Clean 15 mm of the paint for good contact.

4) Insert the cleaned end of the antenna whip into the base 

and tighten two screws.
5) After cutting the antenna do not forget to write down the 

frequency on the label, if it is available.
6) After cutting, measure the antenna VSWR.

All cuts made on antennas 
with phasing coils should 
be made on the bottom rod 
only. Measure the length of 
the rod cut from the lower 
edge of the phasing coil to 
the end of the whip.

*At tuned frequency

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