User's Manual

59
Maintenance / Reference
Problem
Packet
communication does
not function.
APRS does not
function.
Possible Causes
a.TNC is not connected or set
properly. 
b.The unit is not in the packet
mode. 
c.The squelch is open. 
d.The data transmission speed
is not configured. 
e.A PC cable other than the
straight type is used.
a. The unit is not in the packet
mode. 
b. The unit is not configured for
automatic transmission. 
c. The squelch is open. 
d. The GPS receiver is not
geolocating.
Potential Solutions
a.Make sure the connections and
configurations are properly set. 
b.Switch to the packet mode. 
c.Adjust the squelch level where it
will open by reception of a signal.
d.Adjust the speed by the PC. 
e.Use a straight type PC cable.
a. Switch to the packet mode. 
b. Use the PC to set transmission
time separation. 
c. Adjust the squelch level where it
will open by a reception signal. 
d. Wait until the GPS receiver
properly geolocates.
IMPORTANT: When reception frequencies fall in any one of the formulas below, the unit may
receive a non-modulated signal.
This is due to the structure of frequencies of this unit and not a malfunction of the
unit.
• (Reception frequency on the MAIN side - 45.1MHz )
= Reception frequency on the SUB side - 43.4MHz (In u-u)
• (FM reception frequency + 10.7MHz) x 4 = UHF reception frequency - 90.2MHz
• (FM reception frequency + 10.7MHz) x 5 = UHF reception frequency
• (UHF reception frequency - 45.1MHz) x 2
- (VHF reception frequency - 21.7MHz) x 6 = 45.1MHz
• (UHF reception frequency - 45.1MHz) - (VHF reception frequency - 21.7MHz) x 3
= 21.7MHz
• In case you are monitoring the 3 multiple of TX frequency, you may hear your
voice from the unit but this is normal.
EMS-57 DTMF equipped microphone
(This comes standard with the DR-635T)
EJ-50U TNC unit
Optional accessories
EMS-53 Microphone
(This comes standard with the DR-635E)