Specifications

PK-232 OPERATING MANUAL Pactor OPERATION
11.11 Pactor Switching-Time Considerations
For operation in Pactor ARQ, your transceiver or transmitter-receiver
combination must be able to change between transmit and receive within 130
milliseconds. Most modern solid state radios can easily meet this
specification. Many older tube-type radios that use electromechanical
relays also operate very well in Pactor ARQ.
If the changeover from transmit to receive is too long, the minimum
working distance is extended; the signal to the distant station will
arrive before the station has switched back to receive. However, if the
transmitting station is further away, the transmission time over the
propagation path will delay the arrival of the signal until after the
station has switched to receive. For this reason, you may be able to
'Link with' stations across the country, but not across town.
If the receiving station's changeover from transmit to receive is too
slow, the transmitting station delay between “PTT" and “data send" can be
extended. See the ADELAY command in the Command Summary to adjust the PK-
232'B Pactor timing characteristics to compensate for this.
11.11.1 Suggested Pactor operating Settings
If you have trouble synchronizing with another Pactor ARQ station, try
some of the following operating tips before calling Timewave or deciding
that your radio equipment needs modifications:
• Try to work the distant station on the unproto mode to establish that
the other station's system is fully functional.
• Don't use VOX control - use the PTT line from your interface.
• Turn off the AGC circuit - use the RF gain control to prevent receiver
blocking on stronger signals.
• Turn off all compression or other audio processing.
• Keep the AFSK audio input level to the microphone circuit as low as
possible - avoid over-driving the audio input stages.
• Disable the ALC circuit or reduce excessive ALC action; use more
effective RF antenna loading to adjust output power levels.
11.11.2 Possible Areas for Pactor Performance Improvement
If switching-time problems persist, you may have to make changes in the
radio to eliminate excessive time delays:
• Remove large decoupling capacitors from the Push-To-Talk line to allow
faster PTT(transmitter) activation;
• Improve power supply decoupling, especially in audio stages.
• Do not use the squelch control.
In case you can't solve your radio’s switching-time problems, please
call Timewave's Customer Service Department (see the front of this
manual).
2/93 11/15
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