#INTRODUCTION
The Realistic DX
-75
Communications Receiver is desig'ned
to I rvideboth
the usual "long
wave" standard broadcast
recei)tion and'short wave' international
broadcast
recep-
tion. Therefore, it allows the listener to span the oceans
ald travel around the world by means of radio waves.
of radio waves.
Short wave radr,r signals
arcused forlong distance
trans-
nission becausc
of the way they are reflectcd back to
earth by the ionosplx'rc. Radiation frorn space
(primarily
Ironr thc sut)causes ioniz:ltioll olthe loycrs oI gascs higlt
above thc carth. Shott
wrr,rt
r-aclio signals rvill not pcne-
trate t.hcse tonized gascs; rnst.ead,
they bounce back
to
earth much like a stone skips across the surface
of quiet
watcr. Variations in thc reflccting charactcristics of tlre
ionosphere due to sun spots, scasons,
time of day, etc.,
producc periods when the skipping of short wave signals
is espccially effective. Sincc nrany of these
periods
oc-
cur h regular cycles the listener may develop a sched-
ule of the best times to listen for sisnals from distant
Darts
of the world.
Listed below are sone of the many types of broadcasts
[hat can be heard on the short wave bands:
Amateur Radio (Ham)
Mobile Radio - Telepirone
Military
Citizens
Band
(CB)
lnt. Short Wave
(Voice
of America, etc.
)
Standard Time Sigrnls (WWV)
GENERAL
Thc Realistic DX-75 is a four band
AM receiver which
covcrs the standarcl broadcast frequencies in one band:
550 to 1600 KC; and the short wave frequencies in
tlrree
bands: 1.6
to 4.4 MC; 4.5 to fl MC; ll to 30MC.
Utilizing four tubes (one multipurpose tube affords five
tube perf
o rmance
)
plus rec tif ie
r, the supe rhetrodyne c i r -
cuit is designed to operate from a 105 to l25volt, 60 cycle
power source. A power transformer eliminates the haz
-
ard of a hot chassis. Housed in a vinyl clad steel taple
model cabinet, the receiver features an eight inch "slide
rule" type dial with continuous tuning of all four bands,
plus bandspread for precise location of signals on tie
busy short wave bands.