MFJ MFJ-1795W Скачать руководство пользователя страница 4

MFJ-1795W Vertical Antenna                                                                      Instruction Manual 

 

 

Never

 place this antenna in a location that will permit people to encounter the loading 

spokes or any other part of the antenna. 

 

Never

 place this antenna where a mechanical failure might allow the antenna to contact 

power lines or other utility wires. 

 

Always

 ground the feed-line at the point where it enters a building to a good earth ground 

for lightning protection. 

 

Follow

 the guidelines for antenna installations as recommended by the US consumer 

product safety commission. 

 
ANTENNA HEIGHT 
 

The height of the radiating element is adjustable from 5 to 8 feet.  Maximum radiation will be 
obtained by setting the height of the radiating element at 8 feet.  Some installations may require 
the antenna height to be reduced.  An example may be the installation of the antenna inside a 
backyard fence for concealment.  Height adjustment will be discussed in the assembly section of 
this manual. 
 

INSTALLATION 
 

The MFJ-1795W was designed as a low profile, portable antenna. When combined with the MFJ 

Ground-Coupled

™ Portable Antenna Base the antenna will provide permanent or portable 

communications. This is an ideal antenna for restricted locations. However, the antenna 
installation MUST be protected with non-metallic fencing to provide personal safety and to 
prevent antenna damage.  The antenna can be installed using the supplied mounting bracket and 
a suitable ground radial system.

 

 

IMPORTANT

: A suitable ground plane must be installed with this antenna. 

 

PORTABLE SETUP 
 

The antenna may be disassembled to the extent necessary for transporting to a temporary 
location. Before the antenna is disassembled, some type of marks should be placed on the mast 
of the antenna to ensure it will be the same height as before.

 Some retuning may be required 

after moving the antenna.

   

 

WARNING: 

If the antenna falls it will be damaged and may cause serious injury.  

Whatever type of installation you choose, remember that the antenna should be installed 
where it can never
 be contacted by people or animals. 
 
 
TOOLS AND TIME REQUIRED FOR ASSEMBLY 

 

3

 

Содержание MFJ-1795W

Страница 1: ...l Instructions Before Operating Equipment MFJ ENTERPRISES INC 300 Industrial Park Road Starkville MS 39759 USA Tel 662 323 5869 Fax 662 323 6551 COPYRIGHT 2006 MFJ ENTERPRISES INC C Model MFJ 1795W VERSION 1A WARC Band Portable Antenna ...

Страница 2: ...acitance Spokes 8 Loading Coil 30 Meter 4 17 Meter 4 12 Meter 4 Note This drawing is not to scale MFJ 1795W WARC Band Vertical Antenna Always Follow Assembly Instructions Mount Mounting Bracket 1 x 30 30 x 1 Tubing 5 x1 1 8 Tubing WARC Bands Vertical Antenna 1 ...

Страница 3: ...g chart lists the power rating and the 2 1 VSWR bandwidth of this antenna Band Meters Power Watts Bandwidth KHz CW SSB RTTY 60m 700 1500 500 100 30m 1250 1500 750 300 17m 1250 1500 1000 1000 12m 1250 1500 750 2000 The weight and wind load of this antenna are 10 pounds and approximately two square feet respectively WARNING Improper installation and assembly can be hazardous Read these instructions ...

Страница 4: ... INSTALLATION The MFJ 1795W was designed as a low profile portable antenna When combined with the MFJ Ground Coupled Portable Antenna Base the antenna will provide permanent or portable communications This is an ideal antenna for restricted locations However the antenna installation MUST be protected with non metallic fencing to provide personal safety and to prevent antenna damage The antenna can...

Страница 5: ...g MFJ 1795W PARTS LIST As you unpack your antenna you should find the parts in the following list two 2 bundles of wire capacitance spokes eight 8 21 spokes and 14 36 spokes and two 2 spare 21 spokes 5 radiator 1 1 8 30 x 1 radiator 9 x 1 1 8 radiator loading coil assembly base mounting bracket hollow fiberglass rod insulator One Hardware Bag containing 4 1 5 hose clamps bag of short 6 32 stainles...

Страница 6: ...itance hats or you will BREAK the fiberglass form If the terminal lugs loosen tighten the NUT on the lug STEP BY STEP PROCEDURE 1 Prepare a temporary work surface such as a table two saw horses or trash cans to be used while installing the parts onto the antenna 2 Sort out the parts you have unpacked into groups of similar parts Be sure all the parts are available 3 After examining the antenna par...

Страница 7: ...2 into the 60 x 1 1 8 aluminum tubing See Figure 2 Fiberglass Insulator Solder Lug 60 x 1 1 8 Mast Pipe Antenna Feed Point Hose Clamp Figure 2 10 Place one of the hose clamps around the aluminum tubing and snug the clamp using a 5 16 nut driver The center conductor of the coax will be connected to the antenna using a solder lug placed under the clamp Refer to figure 2 11 Place one of the small pla...

Страница 8: ...the next sets of rings 30M Again tighten these spokes as was done in step 9 See Figure 3 and Figure 4 14 Install four 21 capacitance spokes in the remaining two sets of rings 17 12M Again tighten these spokes as was done in step 9 See Figure 3 and Figure 4 15 Slide a hose clamp over the top radiator Mount the top coil assembly to the antenna by inserting the fiberglass insulator in the top radiato...

Страница 9: ...are you installed Then mount the antenna on the short temporary tuning mast or the MFJ Ground Coupled Portable Antenna Base 17 Secure the mounting bracket to the fiberglass insulator as shown in Figure 5 Make sure the antenna mast does not contact the U bolts The next four steps may be skipped if the antenna uses the MFJ 1904 Antenna Base Figure 5 8 ...

Страница 10: ...e the antenna by following the instructions under the section Frequency and SWR Adjustment 21 Mount the antenna in its permanent location Slight retuning and height adjustment may be necessary USING THE MFJ GROUND COUPLED PORTABLE ANTENNA BASE WITH THE MFJ 1795W The antenna base should be assembled using the instructions supplied with the unit The following instructions will explain the installati...

Страница 11: ... Bushing SO 239 Anetnna Base 3 The plastic bushing supplied in the parts should be placed in the hole under the SO 239 connector 4 Now the 15 piece of insulated wire should be passed through the plastic bushing to the antenna feed point SO 239 Bus Wire Figure 7 10 ...

Страница 12: ...ACKET The antenna may be quickly removed to be hidden from view This is easily accomplished by loosening the hose clamp at the base of the antenna shown in Figure 2 Carefully pick up the antenna mast Be sure to watch for overhead tree limbs and other objects that could come into contact with the antenna during removal These objects could cause the antenna to become unbalanced and fall resulting in...

Страница 13: ...e spoke is removed install all the spokes and trim each spoke in 1 4 inch increments The spokes for each band should be cut to the same length Once the resonant frequency is found use the chart located under the section Tuning The Antenna section of this manual to estimate the amount of the spoke length to cut so that the antenna will resonate at your favorite section of the band CAUTION Always st...

Страница 14: ... spokes equals approximately 500 KHz 17 M 1 trimmed off each of the spokes equals approximately 560 KHz 12 M 1 trimmed off each of the spokes equals approximately 570 KHz 3 Now tune progressively higher frequency bands by trimming the spokes Keep each set of capacitance spokes equal in size 30 meters must be the second HF band adjusted 17 the third and 12 meters last After adjusting 12 meters go b...

Страница 15: ... If the manual does not reference your problem or your problem is not solved by reading the manual you may call MFJ Technical Service at 662 323 0549 or the MFJ Factory at 662 323 5869 You will be best helped if you have your unit manual and all information on your station handy so you can answer any questions the technicians may ask You can also send questions by mail to MFJ Enterprises Inc 300 I...

Страница 16: ...er postage and handling 4 This warranty is NOT void for owners who attempt to repair defective units Technical consultation is available by calling 662 323 5869 5 This warranty does not apply to kits sold by or manufactured by MFJ Enterprises Inc 6 Wired and tested PC board products are covered by this warranty provided only the wired and tested PC board product is returned Wired and tested PC boa...

Отзывы: