AEA COMPUTER PATCH CP-1 Instruction Manual page 10

To tune amateur HF teletype signals, set yo ur receiver to lower
sideband, set the audio to a com fortable level and slowly tune your
receiver for a teletype signal. Tune fo r peak bar graph closure and
m inimum flicker. If the LED bar graph flickers on mark-space
transitions, retune until the flickering stops.
CONDITION 1
m ark
tone
I
I I
space
m ark
filte r filte r
Wrong
When you tune your receiver dial, you want to match the RTTY mark
and space tone frequencies up with the respective bandpass filters in
the CP-1, as indicated in condition 2. This proper tune condition w ill be
indicated by the magic-eye style bar graph indicator display with a
peak closure of no more than 6 or 8 bars lit (back off on the volume if
you have more) and no blinking as the tones shift back and forth. You
w ill get a false tuning indication as shown in conditions 1 and 3, if a
peak closure results in a blinking display as the tones shift back and
forth. With practice, you will learn to lock onto a properly tuned
condition very quickly and you w ill gain a deep appreciation for our
unique tuning indicator.
Fbr shifts other than 170 Hz, use the VAR position. The VAR position
uses the VAR shift control to adjust for tone shifts between 100 Hz and
1000 Hz. To use the variable position, first depress the VAR button,
turn the variable shift control full clockwise and tune across the
unknown RTTY signal. Watching the bar graph, tune to the lower pitch
frequency of the two tone RTTY signal. Tune so the LED bar graph is at
peak closure, but flickering. Now adjust the variable shift control
counter-clockwise until you achieve peak closure with no flickering.
NORMAL-REVERSE SWITCH
Some stations use reverse mark and space tone frequencies, usually
accidentally. If you are sure o f the speed and shift of the received
station and receiving 'garbage', try the reverse position.
TELETYPE TRANSMIT
If you are using the RS-232 option, you may have to manually switch
your transceiver to transm it. Again, this depends on your particular
software. The normal com puter TTL inputs can be used for automatic
send/receive switching under software control. The 'AFSK o ut' level
may be adjusted with the rear panel AFSK level control. This level is
preset to 30 mv pp, however, it can be adjusted to 200 mv pp for those
of you who own rigs with a preamp mic such as the ICOM transceivers.
CONDITION 2
space
mark
ton e ton e
I
I
I
m ark
filte r
space
ton e
I
I
space
filte r
Right
CONDITION 3
m ark space
ton e tone
1 1
1
1
space
mark
filte r filte r
Wrong