Minor Components for Use with Tuning Units 2, 3, and 4

housing which has two spring-loaded

f u n c t i o n s as a counterpoise to simulate

binding posts at one end and an N-type con-

earth ground. At the curved top surface of

nector at the opposite end. The uninsulated

t h e cone, three sockets are provided to

e n d s of two wire leads, which are con-

accept the specific number of Mast

nected to the audio or powerline at their

Sections (AB-21/GR) required for res-

opposite ends, are inserted into the binding

onating with the rf signal under measure-

m e n t , as illustrated in TM 11-6625-351-

posts. Any dc voltage present on the lines

under measurement is blocked by coupling

1 2 . The rf signal is conducted from the

capacitors C1401 and C1402. The rf signal

b a s e of the sockets within the antenna

at connector jack J1401 is coupled through

housing by a wire post to the modified N-

the red color-coded coaxial cable of Cable

t y p e terminating connector P1601 at the

A s s e m b l y Set, Electrical MX-3410/URM-

b a s e of the cone-shaped structure. The

85 to the main unit SIGNAL INPUT jack

outside shell of connector P1601 is

f o r amplification, detection, and meter

grounded through the unbalanced injection

presentation.

block (Coupler, Antenna CU-895/URM-85)

e . Coupler, Radio Frequency Interfer-

a n d the rf cables to the ground potential

of the main unit panel.

e n c e C U - 8 9 2 / U R M - 8 5 (G, fig. 38). To

c o n d u c t rf signals or noise interference

b. C o u p l e r, Antenna CU-895/URM-85

s i g n a l s from approximately 500-ohm im-

(C, fig. 38). This coupler, housed in an

p e d a n c e two-wire audio-signal or elec-

i r r e g u l a r - s h a p e d metal and plastic con-

t r i c a l powerlines in the 150-kc to 30-mc

tainer, is provided as a means of coupling

f r e q u e n c y range, another capacitive-type

t h e output of Antenna AS-1158/URM-85

pickup device is employed. Similar in con-

( a above) to the test set. One connector

struction and function to the CU-891/URM-

j a c k , J2002, located at one end of the

8 5 (d above), this coupler has one addi-

coupler, mates the N-type connector plug,

tional circuit component. Resistor R1501,

P 1 6 0 1 , which terminates the base of the

i n series with the ungrounded lead from

b r o a d b a n d antenna. Two connector jacks,

t h e audio-line or powerline coupling ca-

J 2 0 0 1 and J2003, are located adjacent to

p a c i t o r C1501, serves as an impedance-

each other at the opposite end of the

m a t c h i n g device. Effectively, it converts

coupler. These connectors function as

t h e approximate 500-ohm input line to a

follows:

5 0 - o h m coaxial cable jack J1501 to the

(1) Rf s i g n a 1 path connector J2001.

50-ohm impedance so that maximum power

The rf signal is coupled from input

transfer from connector jack J1501 to the

connector J2002 direct to rf output

5 0 - o h m coaxial cable can be effected.

c o n n e c t o r J2001. The red color-

c o d e d coaxial cable of Cable As-

A g a i n , the red color-coded coaxial cable

o f Cable Assembly Set, Electrical MX-

s e m b l y Set, Electrical MX-3410/

3410/URM-85 conducts the rf signal to the

U R M - 8 5 interconnects output jack

main unit front-panel SIGNAL INPUT jack

J2001 to the main unit front-panel

f o r amplification, detection, and meter

SIGNAL INPUT jack. Since the

presentation.

outer shell of the SIGNAL INPUT

jack is at chassis ground potential,

t h e outer shell of jack J2001 and

60. Minor Components for Use with Tuning

the counterpoise are also con-

Units 2, 3, and 4

ducted through to ground potential.

(fig. 38)

The rf signal is conventionally am-

a. Antenna AS-1158/URM-85 The dis-

plified and detected in the test set

c o n e (broadband) antenna (F, fig. 38) is

for presentation on the panel-

u s e d as a nondirectional, relatively con-

m o u n t e d meter.

stant impedance antenna over the wide fre-

(2) I m p U 1 s e generator signal path

q u e n c y range from 20 to 1,000 mc with

connector J2003. When the broad-

t u n i n g units 2, 3, and 4. In operation, it

b a n d antenna over the frequency

is mounted on the AT-1027/URM-85, which

range from 20 to 1,000 mc is used,