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