PK-232 MBX – OPERATING MANUAL FACSIMILE OPERATION
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9.3 System Setup
If you own CSS HF Wefax program, you have the ability to display weather FAX on the
screen of your personal computer. DO NOT USE AN AEA "Y" CABLE WITH THE PK-
232/DSP or PK/232PSK! This manual refers most often to printing FAX on your printer,
but the ideas and commands are similar for using CSS HF Wefax program.
To hook-up the PK-232 for facsimile operation the radio must be connected to either radio
port 1 or 2. If all you want is to receive FAX, you only need to connect the audio from your
receiver. If you wish to transmit as well, follow the instructions in Chapter 3 of this manual
for Radio Connections.
If you are using a CSS HF Wefax program, follow the instructions in the program manual to
run the program with the PK-232.
9.3.1 HF Receiver Settings
Set your HF receiver (or transceiver) to Upper Sideband (USB) unless you have connected
your PK-232 through the direct FSK keying lines. In this case, you should select the FSK
operating mode. Adjust the volume to a comfortable listening level.
9.3.2 Tuning In HF Facsimile Stations
Facsimile is most often found on Upper Sideband and sounds similar to monitoring an AM-
TOR QSO with both stations being of equal strength. The most common facsimile signals
are WEFAX, so we have set the PK-232 FAX default parameters to copy weather charts
and many satellite photographs. We recommend starting start with one of the listed
weather frequencies, or frequencies from Popular Communications in Table 1 when first
receiving facsimile.
Upon tuning into a WEFAX signal, you will notice that the facsimile sound seems to repeat
at the rate of twice a second. This is the the horizontal scan frequency, and allows you to
distinguish different facsimile services by speed. Common horizontal scan rates are 2 lines
per Second, which is typically used in weather facsimile broadcasts, 1-line per Second for
photographs, and 4-lines per second, for some foreign facsimile stations. Listen for these
repetition rates as you tune across the bands in search of new pictures.
The PK-232 uses the 1,000 Hz wideshift filters which have a center frequency of 1.7 kHz
for copying facsimile transmissions. As a result, you must tune 1.7 kHz lower than the fre-
quencies listed in Table 1 when using Upper Sideband. Similarly; in Lower Sideband, one
must tune 1.7 kHz higher than the frequencies listed in the table.
The PK-232 LED bar-graph should be tuned so that the facsimile signal is roughly cen-
tered in the display as shown in the middle of Figure 1 below. If the audio frequency is
too low, the bar-graph will look something like the left-most display. If the audio frequen-
cy is too high, it will look something like the right-most display. Facsimile tuning is not es-
pecially critical when copying WEFAX, but a properly tuned signal is needed when printing
facsimile photographs.
Frequency too low Tuned In Frequency too High
Figure 1: Facsimile tuning indicator conditions for FAX tuning
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