Coaxial Relays and Attenuators

24. Coaxial Relays and Attenuators

through coaxial jack J719 and right-

(fig. 14)

a n g l e adapter CP705. Mating plug

P 7 1 2 conducts the attenuated rf

Figure 14 shows that a network of coaxial

signal through a length of coaxial

r e l a y s and attenuators are connected to

cable to terminal A2 of main unit

the rf signal input and to the impulse gen-

m u l t i p i n connector J701. The cor-

e r a t o r output signal paths. The direction

responding terminal A2 on the

o f signal flow depends on the setting of

m a t i n g plug (at the rear of each

c a l i b r a t i o n switch S706. The following

tuning unit) couples the signal to the

subparagraphs analyze the circuit with

rf tuner section of the tuning unit

S 7 0 6 in the SERIES CAL & OPERATE

in use.

position (a below); then with S706 in the

Note: When the SIGNAL ATTENUATOR

SHUNT CAL position (b below).

DB control is rotated to the 0 SUBST

O N L Y position, a straight-through con-

a. SERIES CAL & OPERATE Position.

ductor coaxial structure is inserted in the

Two signal paths are provided by coaxial

s i g n a l path and no attenuation is intro-

relays K701 and K702.

duced. With this control rotated to the 20,

40, 60, and 80 positions, a 10-, 20-, 40-,

( 1 ) Rf signal path. The rf signal is

or 60- db T- pad coaxial structure is re-

applied to SIGNAL INPUT jack

s p e c t i v e l y inserted in the rf signal path.

J705 and is conducted through

The remaining part of the front-panel des-

a d a p t e r CP701 to input jack J707

ignated amount of signal amplitude reduc-

tion is obtained by the insertion of 10 or

on coaxial relay K701. Setting cal-

20 db additional attenuation in the if. sig-

ibration switch S706 in the SERIES

nal path (para 12b).

CAL & OPERATE position creates

(2) Impulsegenerator signal path. T h e

a path of continuity for the +6-volt

o u t p u t of impulse generator G701

output of the power supply through

is coupled through plug P709 and

the coil of relay K701 and current-

mating jack J713 on coaxial relay

l i m i t i n g resistors R739-R740 to

K 7 0 2 . The coil of relay K702 is

c h a s s i s ground. With relay K701

d e e n e r g i z e d when calibration

energized, the movable arm on the

switch S706 is set to the position

lower set of contacts connects the

shown in figure 14. Therefore, the

incoming rf signal applied at jack

m o v a b l e arm on the lower set of

J 7 0 7 on relay K701 to jack J709.

c o n t a c t s provides a path of con-

The movable arm on the upper set

t i n u i t y through adapter CP704 to

of contacts grounds the output end

front-panel

IMPULSE

OUTPUT

of a 20-db fixed attenuator AT701,

jack J717. The movable arm on the

e f f e c t i v e l y removing it from the

u p p e r set of contacts grounds the

c i r c u i t . The rf signal available at

input end of 20-db fixed attenuator

o u t p u t jack J709 on the coaxial

AT701, effectively removing it

relay is applied through plug P703,

from the circuit. When the discone,

cable assembly W701, and plug

l o o p , or vertical antenna is con-

P 7 0 4 to coaxial jack J718 on the

nected to the main unit, one of the

input side of the turret-type rotary

pair of rf cables in Electrical

switch on signal attenuator AT702.

C a b l e Assembly Set MX-3410/

When the SIGNAL ATTENUATOR

U R M - 8 5 mates with the output of

db control is rotated to the 0 CW

the impulse generator at IMPULSE

O N L Y position (fig. 14), a 10-db

OUTPUT jack J717. Each of these

r e s i s t i v e T-pad attenuator network

three antennas, with the use of the

o f coaxial structure is inserted in

s e r i e s method of calibration (fig.

t h e signal path. The attenuated rf

3 ) , houses a self-contained 20-db

signal, available at the output end

attenuator.

o f the coaxial structure, is picked

up by the output side of the turret-

b . SHUNT CAL Position. T h e circuit

t y p e rotary switch and is coupled

conditions with calibration switch S706 in