DZ HT-7, Инструкция по сборке, Страница: 4 / 44

Page 4
In the early days of amateur ra ‐
dio, and continuing well into the
1960’s, amplitude modulation (AM)
was the mode of choice for phone
communications. Its wide band ‐
width (6kHz) and rich sound made
ham radio sound like broadcast
stations.
Eventually, with crowded bands
and a desire for smaller rigs, AM
gave way to single ‐ sideband (SSB)
operation. Radios had more sensi ‐
tivity on SSB than with AM, so
worldwide contacts became easier.
AM was relegated to “calling fre ‐
quencies” ‐ just single frequen ‐
cies in the large amateur phone
bands where AM aficionados could
still enjoy the fun of those old ‐
style QSOs, which were typically
long ‐ winded, since VOX was not
used and switching over from
transmit to receive took longer.
Now you can enjoy the fun of AM
without spending an arm and a leg
with your new HT ‐ 7 Handie ‐ Talkie.
Not only can you use it as a
walkie ‐ talkie, with limited
range, but you can, with an ap ‐
propriate outside antenna, talk
to the “big guns” on the 40M AM
calling frequency of 7.290MHz.
Since the output power of the HT ‐
7 is just 2 Watts, you may want
to add an amplifier, but when
band conditions are good, and the
sunspot cycle cooperates, you
will be amazed at how far 2 Watts
will carry!
Thanks for trusting in DZKit to
provide not only unique elec ‐
tronic products, but to give you
hours of building fun too.
INTRODUCTION