Inovonics 525N, Installation & User Manual

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A solid, strong incoming carrier, preferably 40dBuV or more,
will usually guarantee adequate SNR for accurate modulation
readings. But even a strong signal can be sabotaged by co-
channel ‘skip’ after daylight hours. Watch for a ‘beat’ on the
RSSI display and listen for an intruding program at the re-
ceived frequency.
A strong adjacent-channel signal can also skew peak modula-
tion readings. The 525N is, after all, a very wideband receiver.
Although synchronous detection should reject an adjacent
channel, the 525N compromises this feature somewhat with its
very tight carrier phase lock, which is necessary to reject the
effects of incidental phase modulation that might be present in
the desired signal.
The front-panel
NOISE:
reading will reveal several reception
anomalies including adjacent-channel signals that may not be
audible in the program audio. Use the signal-nulling capability
of the loop antenna to reject an intruder and to optimize the
desired signal.
Performance
Limitations
Although the Model 525N carries the name “Reference Receiv-
er,” don’t be too disappointed if performance seems to fall
short of that old Philco console your granddad might have had
or, for that matter, a contemporary car radio. This is a very
wideband unit that works on a different principle from most
AM radios, in that it wants to lock onto a strong, clean carrier,
even if that carrier is a channel or more away!
The principal utility of the 525N is its use as a Modulation Mon-
itor, not as a hotshot receiver with razor-sharp tuning. Alt-
hough the 525N can log some respectable DX on clear chan-
nels, there may well be reception limitations even when the
525N is within sight of the transmitting tower.