Known issues with the AR8600MK2 IF signal output
By design, the AR8600MK2 IF signal’s center frequency might flu/-10kHz from
its center frequency 10.7MHz. Fortunately ARD300 is able to compensate for this
shifting by searching for and locking to the IF signal peak. Nevertheless it has been
noticed that in some cases of a strong signal close to the tuned frequency, ARD300
might wrongly lock to the adjacent signal rather than on the IF center signal, and
therefore miss the digital signal to decode.
Specificity to D-STAR decoding: Whenever ARD300 has to search for the IF peak to
lock onto, it might in some cases miss the call-sign information which is located in the
signal header, at the very beginning of each transmission.
By factory default, the IF signal of AR8600MK2 is output in WFM mode only to
minimize the effects of internal spurii. Using SEARCH to find narrow-band digital
transmissions in WFM mode can produce unexpected results as the receiver might not
to stop on the signal’s exact frequency. This is not an issue when using the SCAN
function or simple VFO reception.
Fortunately there are 2 workaround solutions to obtain IF in ALL MODES, by applying
simple hardware modifications to the receiver:
Receiver status
IF OUT
frequency &
mode
ARD300
selection
Operating characteristics
1. Factory default
10.7MHz
WFM only
AR86 10
SEARCH results unreliable due to
too wide mode.
2. Hardware modified
for all mode IF out.
10.7MHz
All modes
AR86 10
NFM can be used for SEARCH
3. Hardware modified
to change IF to
45.05MHz
45.05MHz
All modes
AR86 45
NFM can be used for SEARCH but
receiver sensitivity decreased by
9dBm.
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