Bird Technologies 4450 - Manual (Page 11)

Chap ter 1
In tro duc tion
Purpose and function The Model 4450 Thruline Wattmeter is an in ser tion-type RF wattmeter de signed to mea sure RF
power flow and load match in 50 ohm RF co ax ial trans mis sion lines. Its pri mary in tended use is
for the test and eval u a tion of power line car rier equip ment, al though it is well suited low fre -
quency low power RF ap pli ca tion. When used in a 50 ohm ap pli ca tion, with N type con nec tors, it
has an in ser tion VSWR of less than 1.10 for fre quen cies from 25W and 0 to 100W to cor re spond
with the range switch (S-2) set tings.
This unit will not only give for ward power in di ca tions with a high de gree of ac cu racy, but also
will in di cate re flected power with a turn of mode switch S-1.
Description The Model 4450 Thruline Wattmeter is a por ta ble unit con tained in a formed alu mi num hous ing,
with formed sheet alu mi num back clo sure which is eas ily re moved. The unit is equipped with a
leather strap for car ry ing, four rub ber shock feet on the base, and four rub ber bump ers on the back,
which al low the unit to be used stand ing ver ti cally or hor i zon tally. The me ter is spe cially shock
mounted for ad di tional pro tec tion and has a slot ted ad just ment screw on the front face of the me ter
be zel for me chan i cal ze ro ing ad just ment. Just be low the me ter on the front face is a mode switch
for se lect ing power range or OFF po si tion. On the sides of the unit are the RF con nec tors which
are la beled for in put and out put.
Performance
Characteristics and
Capabilities
The Model 4450 Thruline Wattmeter is ca pa ble of mea sur ing RF power up to 100 Watts in three
ranges: 5, 25, and 100 Watts. These power lev els are se lected by ad just ing the range switch and
can be used for ei ther for ward or re flected power by ad just ing the mode switch to RFL or FWD
po si tion. When check ing re flected power greater res o lu tion can be ob tained by se lect ing a lower
power set ting on the range switch.
If nec es sary, the in put and out put con nec tions may be re versed with out loss of ac cu racy; how ever,
the mode switch will be just the op po site of nor mal set tings, i.e. RFL po si tion will in di cate for -
ward power and FWD po si tion will in di cate re flected power.
The RF con nec tors are the Quick-Change (QC) type and may changed to other avail able QC types
if nec es sary.
Power Requirements The Model 4450 Thruline Wattmeter has no bat ter ies and re quires no out side util ity power source
for op er a tion other than the RF power to be mea sured. This makes the unit es pe cially suited for
mo bile, ma rine, and field use.
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