Fm Transmission; Fm Repeater Operation - Kenwood TS-870S Instruction Manual

6 COMMUNICATING

FM TRANSMISSION

FM operation on HF frequencies solves the problem of
how to have long distance voice communication with
the finest audio quality. When combined with the
full-quieting aspect of FM signals that suppress
background noise on the frequency, FM can be the best
method for maintaining regular schedules with friends.
And when conditions are unusually good allowing
simplex FM contacts over intercontinental paths, you
may feel as though you are using your local VHF
repeater to talk across town instead of using the HF
spectrum for multi-hop communication.
Refer, if necessary, to "OPERATING BASICS"
beginning on page 19 for complete receiving details for
any mode.
Switch ON Menu No. 12 (FM.S-MET) if you prefer. This
Note:
function applies a correction for the S-meter when operating on FM.
This correction will adjust S-meter readings to be equal with other
KENWOOD HF transceivers.
1 Select the operating frequency.
2 Press [FM/AM] to select FM mode.
AGC AUTO
3 Press [MONI] to switch the Monitor function ON.
• "MONI" lights.
4 Press and hold down the Microphone [PTT] switch,
or press [SEND].
• The "ON AIR" indicator lights.
• Refer to "VOX" {page 45} for information on
automatic TX/RX switching.
5 Speak into the microphone.
• FM microphone gain can be switched between
low (L) or high (H) via Menu No. 61 (FM MIC).
The default is low (L). Low is usually appropriate;
however, select high if the monitored audio or
reports from other stations indicate that your
audio is weak. The Front Panel MIC gain control
has no affect in the FM mode.
• Speak in a normal tone and level of voice.
Speaking too close to the microphone, or too
loudly, may increase distortion and reduce
intelligibility.
• The CAR control does not need to be adjusted
since the carrier level is fixed at the best setting
for the FM mode.
6 Release the Microphone [PTT] switch, or press
[SEND] again, to return to the receive mode.
• The "ON AIR" indicator goes out.
Note:
◆
When using the optional MC-90 in FM mode, the microphone
sensitivity is low, and this may cause insufficient modulation. Use
Menu No. 61 to select high microphone gain.
◆
When the target station is using FM wide-band deviation, you
also must select wide-band deviation (Menu No. 60). If you
transmit using the narrow band against this rule, the target station
will receive your audio less clearly.
38
FM

FM REPEATER OPERATION

Compared to the usual simplex method of FM
communications on HF, which is radio to radio with
antennas at or slightly above average terrain, you can
often transmit much farther through repeaters.
Repeaters are typically located on a mountain top or
other elevated location. Most often they operate at a
higher ERP (Effective Radiated Power) than the
average mobile or fixed amateur station. This
combination of elevation and high ERP allows
communications over wider and longer distances than
can be achieved by the average station.
HF repeaters operate only in the 29 MHz FM sub-band.
This special service combines the advantages of FM
operation, good fidelity with noise and interference
immunity, with the excitement of HF DX (long distance)
communications. Even on a quiet day, 10 meter FM
provides reliable around-town communications with the
potential for sudden DX from across the country or
around the world.
Note: Switch ON Menu No. 12 (FM.S-MET) if you prefer. This
function applies a correction for the S-meter when operating on FM.
This correction will adjust S-meter readings to be equal with other
HF transceivers.
KENWOOD
29.520 MHz
88.5 Hz
29.620 MHz
1 Press [RX B] (or [RX A]).
• The VFO selected in this step will be used for the
transmit frequency.
2 Select the transmit frequency.
3 Press [FM/AM] to select FM mode.
AGC AUTO
4 Press [A=B].
5 Press [RX A] (or [RX B]).
• This must be the VFO that was not selected in
Step 1.
29.620 MHz
29.520 MHz
88.5 Hz
FM