Timewave PK-900, Operating Manual

Page: 146 / 392

9.4 Black & White FAX Operation
This mode of black & white FAX operation will eventually be deleted
from the PK-900 since the Analog mode has been created. Still, if
you own an older AEA PAKRATT WITH FAX program, you should have the
ability to display weather FAX on the screen of your PC. If you are
using an AEA PAKRATT WITH FAX program, follow the program manual
instructions to run the program with the PK-900.
To hook-up the PK-900 for facsimile operation the radio must be
connected to Radio Port 1. 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 complete Radio Connections.
NOTE: Facsimile transmissions contain such a large amount of data
that the PK-900 can not support Packet operation on Radio
Port 2 while in the Facsimile mode.
9.4.1 HF Receiver Settings
Set your HF receiver (or transceiver) to upper Sideband (USB) and
disable any IF-Shift or Passband-tuning controls. Adjust the volume
to a comfortable listening level.
9.4.2 Tuning In HF Facsimile Stations
Facsimile is most often found on Upper Sideband and sounds similar to
monitoring an AMTOR QSO with both stations being of equal strength.
The most common facsimile signals are WEFAX, so we have set the
PK-900 FAX default parameters to copy weather charts and many
satellite photographs. We recommend starting 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
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-900 uses a center frequency of 1.9 kHz for copying facsimile
transmissions. As a result, you must tune 1.9 kHz lower than the
frequencies listed in Table 1 when using Upper Sideband. Similarly,
in Lower Sideband, one must tune 1.9 kHz higher than the frequencies
listed in the table.
1/93 9-4