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USER'S GUIDE
Don't be afraid to try other values in these parameters. You won't hurt your PK-232 by
changing timing values. On the contrary, you may improve your packet performance.
5.5.4.1.
TXDELAY
Radios vary greatly in the time delays that occur when switching from receive to trans-
mit and from transmit to receive. These switching-time delays affect both ends of the
Packet link:
o Time delay between the moment that your PK-232 keys your transmitter's PTT line
and your transmitter delivers power to your antenna.
o Time required for the distant station's receiver to recover full sensitivity and over-
come squelch/AGC rise-time characteristics.
o Transmitter and receiver phase-lock loop settling times at both ends of the link.
If your PK-232 starts sending data before your transmitter is up to power, or before
your receiver has recovered from transmitting and locked up on the incoming signal,
the packet will not be received properly at the distance end.
TXDELAY
switching.
TXDELAY
your PK-232 starts sending data. During the period in which your PK-232 is holding PTT
active but not sending data, your PK-232 transmits a series of contiguous synchronizing
signals (flags).
5.5.4.2.
AXDELAY and AXHANG
You may require a longer key-up delay when sending packets through an audio repeat-
er than normally needed for direct communications. However, the extra key-up delay is
not required if the repeater has not had time to "drop" since the last transmission.
AXDELAY
o The
ter receiver and transmitter have time to lock up.
AXHANG
o The
peater to drop.
If your PK-232 has detected channel activity recently enough so that the repeater trans-
mitter might still be on, it will wait only
AXDELAY
adding
TXDELAY
,
effect, the total key-up delay is:
Key-up delay = (
5.5.4.3.
FRACK and RETRY
The AX.25 protocol calls for retransmission of packets when an acknowledgement is not
received from the distant end of the link within a specified period of time. A packet
might not be acknowledged because of channel noise or "collision" with another packet
transmission. If other stations are using the same channel, the receiving station may
not be able to acknowledge the received packet immediately.
PK232UG Rev. B 9/86
must be taken into account in cases where external amplifiers use RF-driven
controls the delay between your transmitter's key-up and the moment when
command adds more key-up delay in your PK-232 so that the repea-
command sets the time your PK-232 assumes is needed for the re-
time as well.
AXDELAY
AXHANG
and
TXDELAY
+
TXDELAY
time before sending data, rather than
set times in units of 10 milliseconds. If
AXDELAY
) × 10 milliseconds.
5-9
ADVANCED PACKET OPERATION
AXDELAY
is in
100
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