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1mm=39.37mil 1cm=10mm=0.3937” 1m=100cm=3.281ft 1kg=2.205lbs 1m

2

=10.764sq.ft 

1km/h=0.62137mph

 

 

ACOM LS108 

HF Log-periodic Antenna 

 

ASSEMBLING MANUAL 

 
 

1. GENERAL 

INFORMATION 

 
ACOM manufactures a range of antennas designed and produced to give top performance and reliable long-
lasting service. They are completely manufactured of non-corrosive materials. The antennas come partly 
factory-assembled in order to facilitate and expedite your labor. 
 
1.1.  Introduction and Description 
 
This manual explains the assembling of the ACOM LS108 HF Log-Periodic Antenna. The LS108 is a 
directional wideband antenna that covers the HF spectrum between 14 and 30 MHz continuously. It can be 
used with the full legal power of 1500W continuously or 3000W PEP. 
 
1.2.  Owner Assistance 
 
If assistance or service is needed, your local dealer should be contacted first. In the unlikely event you need 
further information, you may get in touch with ACOM by facsimile, telephone, email, or standard mail. Fax: 
(+359 2) 920 9656; telephone: (+359 2) 920 9655; e-mail: [email protected]; standard mail: ACOM, 
Blvd. N. Mushanov 151, 1330 Sofia, Bulgaria. 
 
1.3.  Specifications 
 

Number of elements 

10 

Frequency coverage 

14-30 

М

Hz continuously 

Gain (average) 

9.5 dBi  

Front-to-Back Ratio 

20 dB 

Nominal Input Impedance 

50 Ohm 

SWR (typ) 

1.5 : 1  

Maximum Input Power  

1500 W continuously 
3000 W PEP 

Boom Length 

8 m (26.25 ft) 

Boom Diameter 

50 mm (1.97”) 

Mast Diameter 

50 mm (1.97”) 

Longest Element  

11 m (36.1 ft) 

Turning Radius 

6.8 m (22.3 ft) 

Wind-load Area 

1.5 m

(16,15 sq.ft) 

Wind Survival (no ice) 

145 km/h (90.0 mph) 

Weight 

Operating 30 kg (67 lbs) 
Shipping 36 kg (80 lbs) 

Connectors: antenna / coaxial feed line 

SO239A / PL259 

 

1.4.  SAFETY FIRST! 
 
Get acquaint with and observe strictly the requirements and instructions of your local legislation. Direct 
grounding of the antenna and the tower structure is essential as protection from lightning strikes and static 
electricity. The entire earth-connection system must meet your local standard requirements.  
 
Do not install the antenna close to power lines and cables, as their proximity, arc-over or contact with them 
during assembly, installation, and exploitation is hazardous and can be lethal. 
 
Do not work alone! You must have at least one assistant always when you work on the antenna. If you have 
any doubt concerning the safety, please consult your dealer or engage a professional company.  
 

WARNING! 
Exposing to strong electromagnetic radiation can result in dangerous maladies or death. Do not 
allow people or animals around the antenna during operation and exploitation. 

Summary of Contents for LS 108

Page 1: ...ASSEMBLING MANUAL LS 108 HF Log Periodic Antenna 14 30 MHz ...

Page 2: ...30 МHz continuously Gain average 9 5 dBi Front to Back Ratio 20 dB Nominal Input Impedance 50 Ohm SWR typ 1 5 1 Maximum Input Power 1500 W continuously 3000 W PEP Boom Length 8 m 26 25 ft Boom Diameter 50 mm 1 97 Mast Diameter 50 mm 1 97 Longest Element 11 m 36 1 ft Turning Radius 6 8 m 22 3 ft Wind load Area 1 5 m2 16 15 sq ft Wind Survival no ice 145 km h 90 0 mph Weight Operating 30 kg 67 lbs S...

Page 3: ...r blocks and each element is driven by the phase line 2 1 Boom Assembly The boom is composed of four pieces sections which are to be assembled together The section ends to be joined together are marked by letters A A B B and C C directly on the tubes Sections have the element supporting insulators mast bracket balun transformer and the boom guys readily installed in the factory You will find the r...

Page 4: ...nstallation They have the same marking 1L and 1R Lay the two half elements in the corresponding channels Select two bolts M5x60 mm and place a plain flat washer on each bolt Align the mount holes of the half elements and the insulator Push the two bolts upside down through insulator and half elements Use the holes located next to the boom Please note that the bolts heads are underside of insulator...

Page 5: ...arest strap insulating spacer located between ELEMENT 10 and ELEMENT 9 Together with the cable fasten also the legs skirts on the two strap spacer sides see Fig 5 Phase line straps mounting Continue fastening the cable with two ties at each spacer until you reach the mast Now fasten also the strap insulating spacers in the other part of the boom although there is no cable there 2 6 Boom to Mast As...

Page 6: ...sulator and get the element horizontal Now tighten properly all the nuts that hold the phase line remember the caution note in S 2 4 Attachment of Phase line Straps Do not over tight Check all antenna dimensions per Table 1 Half Element Lengths and Fig 9 LS108 Dimensional Drawing before to start lifting the antenna on your permanent tower structure Check the quality of all mechanical and electrica...

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