External Speaker - Icom IC-551D Instruction Manual

The connection of the DC power cord supplied with the 1С5510 is done in the following way:
First make sure that the power switch of the unit is in the OFF position and the T/R switch is in
the receive position. Connect the cord to the DC power supply with the RED lead to the positive
terminal and the BLACK lead to the negative terminal. (Reverse connection will cause the pro-
tection circuit to operate and blow the fuse.) Connect the DC plug to the socket on the rear panel
of the IC-551D. Refer to the drawing below.
нпинпити КЕБЕКЕШИ ЕЕ
For АС operation
NBRERSESRERKREESRASEAR - : — —_ AC POWER
С
|
OUTLET
For DC operation
бв) © BATTERY
о г
(е)9 ОС POWER SOURCE
(12 ~ 15V - 204)
ОС POWER CORD
ANTENNA
The most important single item that will influence the performance of any communication system
is the antenna. For that reason, a good, high-quality, gain antenna of 50 ohms impedance is recom-
mended, fixed or mobile. In VHF as well as the low bands, every watt of ERP makes some dif-
ference. Therefore, 80 watts average output plus 3dB of gain antenna equals 160 watts ERP,
presuming low VSWR of course. The few more dollars inversted in a gain type antenna is well
worth it. When adjusting your antenna, whether mobile or fixed, by all means follow the manu-
facturer's instructions. There are some pitfalls to be-aware of. For example, do not attempt to
adjust ап antenna for lowest VSWR when using a diode VSWR meter not engineered for VHF
applications. Such readings will invariably have an error of 40% or more. Instead, use an in-line
watt meter similar to the Drake WV-4, Bird Model 43 or Sierra Model 164B with VHF cartridge.
Further, when adjusting a mobile antenna, do so with the motor running preferably above normal
idling speed. This will insure proper voltage level to the transceiver.
The RF coaxial connector on the rear chassis mates with a standard PL-259 connector. Some
models may have metric threads. In any event, the RF connector will mate with almost any
PL-259 connector if care is taken to seat them properly.
EXTERNAL SPEAKER
The IC-551D contains an internal speaker, and is also designed so that it can drive an external
speaker from the external (EXT) speaker jack on the rear panel. Be sure the impedance of the
external speaker is 8 ohms, and remember that with the external speaker connected, the internal
speaker is disabled. |
HEADPHONES
Any good headphone set, including stereo type, that has 4~16 ohms impedance can be used.
With the plug inserted halfway into the PHONES jack, both the headphones and speaker will
operate. This is convenient when others wish to listen in on the station, or you wish to record