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4.7 HF Packet Operation<br />
HF Packet is much trickier than operating on VHF. In this section we<br />
will assume you have as completed section 4.2 of this chapter and at<br />
least read section 4.3 and the MONITORING sections of 4.4. If at all<br />
possible, get some experience with VHF packet before trying packet on<br />
HF. Although this is not absolutely required, the experience will<br />
help you make HF packet contacts.<br />
4.7.1 Where to Operate HF Packet<br />
Before you can operate HF Packet, you find the activity. Most HF<br />
packet operation is on the 20-meter amateur band starting at 14.103<br />
MHz and every 2 KHz above that up to 14.111 MHz. Note that 14.103 MHz<br />
is the calling frequency and a good place to start. The higher<br />
frequencies such as 14.109 and 14.111 are used mostly by HF PBBS<br />
systems and are not good places to look for a QSO.<br />
4.7.2 <strong>PK</strong>-<strong>232</strong> HF Packet Settings<br />
Make sure your <strong>PK</strong>-<strong>232</strong> is turned ON and your PAKRATT or terminal<br />
program is up and running. Then change the following <strong>PK</strong>-<strong>232</strong><br />
parameters for 300 baud HF Packet. The VHF settings are also shown to<br />
make it easier to switch back to VHF when finished.<br />
300 baud HF Packet 1200 baud VHF Packet<br />
SLOTTIME 8 SLOTTIME 30<br />
PACLEN 64 or less PACLEN 128<br />
MAXFRAME 1 MAXFRAME 4<br />
FRACK 15 FRACK 8<br />
HBAUD 300 HBAUD 1200<br />
VHF OFF VHF ON<br />
The last two of these commands are the most important.<br />
If you fail to set the VHF parameter to OFF, the VHF modem will remain<br />
on and you will not be able to copy packets. Similarly, if you do not<br />
set the packet baud rate (HBAUD) to 300, you will be operating at a<br />
different speed than everyone else and not be able to copy any packets.<br />
You should set MONITOR to 6 when you first try to tune in HF packet.<br />
4.7.3 HF Receiver Settings<br />
Set your HF receiver (or transceiver) to Lower Sideband (LSB) unless<br />
you connected your <strong>PK</strong>-<strong>232</strong> through the direct FSK keying lines, in<br />
which case you should select the FSK operating mode. Adjust the<br />
volume to a comfortable listening level.<br />
4.7.4 Tuning-in HF Packet Stations<br />
Perhaps the most difficult thing about HF Packet operation is making<br />
sure the station you are talking to is tuned properly and stays tuned.<br />
Since HF packet uses 200 Hz Frequency Shift Keying to send data<br />
(2110/2310 Hz), tuning accuracy is very important. Being off<br />
frequency by only 20 Hz makes a noticeable difference in the <strong>PK</strong>-<strong>232</strong>'s<br />
ability to copy packet stations. Follow the tuning procedure below<br />
carefully for the best results in tuning in HF packet stations.<br />
4/91 4-23<br />
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