Comet GP-285 Instruction Manual

VSWR Reference data at 144MHz
VSWR
2.0
1.8
1.6
1.5
1.4
1.3
1.2
1.1
1.0
140MHz 145MHz 150MHz
Length A : 1325 mm
Length : 870 mm
B
PRECAUTIONS for Installation
!
● Wearing a safety hat and a life line during installing on a roof top or any high places is highly recommended.
● Erect this antenna in a safe place Check if the Cable Connector fits into the Antenna Connector.
● Make sure all nuts, bolts and screws are securely tightened. Failure to follow this would cause a serious
accident or performance degradation.
● Check if waterproofing at each connection is appropriately done. If not, it would cause short-circuit and/or
corrosion.
● Do not erect this antenna near any electrical power lines, steel towers and/or buildings. Such objects would
cause performance degradation.
! PRECAUTIONS for Operation
●Do not touch the antenna while transmitting, otherwise you would get burned.
●Do not touch the antenna or coax cables while lightning. Checking VSWR after lightning is highly recommended.
●Do not use this antenna outside its specification. Failure to follow this would damage the antenna.
●Make sure to adjust the antenna in a right way. Higher VSWR could cause the performance degradation.
●Never attempt to fix or modify this antenna by yourself.
【 】
Maintenance
■ If any unusual situation happens, stop using immediately and ask the local agent you purchased this product.
■ Confirm if the product works normally before operating.
■ Be sure to change the parts which have strength poverty or deformation across the ages etc.
Specifications or appearance is subject to change without notice.
COMET CO.,LTD.
4-18-2, Tsuji, Minami-ku, Saitama-shi, Saitama-Pref, 336-0026, JAPAN
TEL : 81-48-839-3131 / FAX : 81-48-839-3136
URL : http://www.comet-ant.co.jp/english
Vertical Beam Pattern Image
Jan.2019 1st edition. Printed in JAPAN.
Copyright (C) 2019 COMET CO.,LTD. All Rights Reserved.
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GP-285
VHF Band
MODEL
5/8 λ 2-stage Collinear Antenna
Thank you for purchasing our products.
For your safety :
Read this manual carefully for proper handling and operation before using.
Keep this manual in a safe place for future reference.
【 Features 】
●This product is a 5/8λ 2-stage high gain GP antenna.
●By adjusting the element length, VHF band amateur band (144-148 MHz) was included.
It can be used in the range of 135 to 175 MHz.
●High withstand input 500 W antenna.
【 Specifications 】
Frequency band : 135 - 175 MHz (by adjustment of element length)
Antenna type : 5/8 λ 2-stage collinear antenna
Gain : 5.15 dBi
Polarization : Vertical (omnidirectional in horizontal plane)
VSWR : 1.5 or less
Band with VSWR 1.5 or less : 2 MHz (at 135 MHz) , 4 MHz (at 175 MHz)
Band with VSWR 2.0 or less : 4 MHz (at 135 MHz) , 8 MHz (at 175 MHz)
Max.Input Power : 500 W (CW)
Lightning protection structure : DC Grounded
Overall length : Max. 3.34 m (135 MHz) , Min. 3.0 m (175 MHz)
Wind speed : Max. 50 m / s
Wind receiving load : Max. 142 N
2
Wind receiving area : Max. 0.115 m
Weight : approx. 2.3 kg (except mount bracket)
Connector : SO-239 (M-J)
Parts List
① Top element A (w/ Feeding section) ... 1 set
② Bottom element (L:1760mm) ... 1pc.
③ Top element B (L:840mm) ... 1 pc.
④ Radial element (L:430mm) ... 8pcs.
⑤ Hose clamp (Small) ... 1pc.
First of all, please check whether ⑥ Hose clamp (Large) ... 1pc.
there are parts as per the parts list.
Assembling the bottom element part
1. Four radial clamps and four radial pipes become
one radial unit.
Temporarily assemble as shown in the fig.1 , and
combine it up and down two units.
⑦ Radial clamp
⑧ Hex Bolt
⑨ Tooth Washer
⑩ Hex Nut
Instruction Manual
⑦ Radial clamp ... 8pcs.
⑧ Hex Bolt (No.10x24 5/8")... 32pcs.
⑨ Tooth Washer [Internal] (No.10)... 32pcs.
⑩ Hex Nut (No.10x24) ... 32pcs.
⑭ Spring Washer (M6) ... 6pcs.
⑪ U-Bolt ... 2pcs.
⑮ Hex Nut (M6) ... 6pcs.
⑫ Mount Bracket ... 2pcs.
⑬ Hex Bolt (M6x30) ... 2pcs.
④ Radial element
Fig.1
Set of Radial unit.
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