3 English language operating manual addendum V1.3 20/10/99
©AOR LTD, 1997, 1998, 1999 E&OE - Page
1
3 OPERATING MANUAL ADDENDUM
The 3 is a ‘feature loaded’ version of the AR5000 receiver with three enhanced facilities which can only be fitted in the factory
during manufacture:
●
Synchronous AM
●
Automatic Frequency Control
●
Noise blanker
1. Synchronous AM
Synchronous AM is a useful tool to help reduce distortion due to selective fading, in particular on the short wave bands (long & medium wave bands too).
In synchronous AM, the original carrier is phase locked to a stable internally generated synthetic reference which is used to replace the (variable) original
carrier resulting in more stable reception with greater recovered audio, especially during deep fades. A wide lock rage is provided by this detector to enable
simple, quick & efficient operation (unlike some other synchronous units on the market which require extremely accurate tuning).
SAM
Synchronous AM double side band
SAL
Synchronous AM lower side band
SAH
Synchronous AM upper (higher) side band
AM transmissions are constructed of a carrier and both upper & lower sidebands. Usually both side bands carry the same information so both or either
may be selected with the same recovered resulting audio, however when adjacent interference is present, selecting synchronous single side band
(SAL or SAH) can provide improved results.
The
key is used to select synchronous AM in the same manner as other receive modes via the
SUB DIAL
, the list of mode has simply become
longer:
AUTO FM AM LSB USB CW SAM SAL SAH
2. Automatic Frequency Control (A.F.C.)
Automatic frequency control is a ‘global’ facility, either OFF or ON (default is off). When A.F.C. is used in AM, FM and synchronous AM modes, the
receiver is automatically tuned on to the centre frequency to provide the best signal strength and recovered audio. When used in synchronous AM modes,
A.F.C. ensures that the signal is pulled within lock range for no-fuss operation. A.F.C. is particularly useful on the VHF-UHF bands to ensure that the
AR5000 is receiving spot on frequency, especially when searching through unusual band plans or when the exact band plan is not known.
Restrictions:
a. A.F.C. does not operate on USB, LSB or CW modes
b. If you are tuned many kHz off frequency (so that there is little recovered audio), you may be outside of A.F.C. range.
c. A.F.C. may not exactly centre FM reception when using a wide filter such as 110 kHz or 220 kHz.
d. The last three right hand digits of frequency readout (Hz, tens of Hz and hundreds of Hz) will be removed and replaced with the letters
“
AF
” to indicate that A.F.C. is in operation.
A.F.C. is switched ON/OFF using the OPTION menu while in VFO, SEARCH or SCAN modes.
Press
then
to access the options menu. “AFC” is the first option on the list:
AFC OFF
<<<<
NB OFF
DTMF OFF
T-ELMT OFF
Use the
SUB DIAL
to toggle the A.F.C. OFF/ON. Press
to accept any changes or press
to abort selection. When A.F.C. is switched on,
a typical display may look like:
Depending upon how far the A.F.C. has to correct centre frequency, the process may take a few seconds.
3. Noise blanker
The noise blanker is another a ‘global’ facility, either OFF or ON (default is off). This facility is
particularly useful to help reduce impulse noise and interference from vehicles ignition systems, whether from passing traffic or while the AR5000 is fitted
into a mobile installation.
The noise blanker is switched ON/OFF using the OPTION menu while in VFO, SEARCH or SCAN modes.
Press
then
to access the options menu. “NB” is the second option on the list:
AFC OFF
NB OFF
<<<<
DTMF OFF
T-ELMT OFF
Use the
SUB DIAL
to toggle the noise blanker OFF/ON. Press
to accept any changes or press
to abort selection. There is no visual
indication to show the status of the noise blanker, however it is fairly obvious when switched off/on as ignition noise will be heard!