Rf Shielding - AEA COMPUTER PATCH CP-1 Instruction Manual

If you own a transceiver with a RTTY mode position, then you may
desire to m odify your CP-1 as per Appendix D to use FSK. If you wish
to use AFSK, then you must use lower sideband and use the mic input
of the transceiver. For those of you who wish to use 850 Hz shift on
transmit, refer to Appendix E on how to m odify your CP-1.
300 BAUD OPERATION
The low pass filte r is optim ized fo r CW and RTTY rates less than 100
baud. To use 300 baud, parallel R77 with a 16 K ohm 'A watt resistor.
WARNING
Most amateur transm itters are NOT capable of 100% duty cycle full
power input on Radio Teletype (RTTY) transmission). If your
transm itter manual does not have operating instructions for RTTY, we
suggest one-third to one-half the normal CW input power level. Be
sure to disconnect your m icrophone to prevent sounds in the shack
from being transmitted.
CW INDENTIFICATION
In teletype operation the AFSK mark and space tones are 2125 and
2295 Hz, respectively. If the CW input line is activated during RTTY
operations, a narrow shift (approxim ately 50 Hz) AFSK CW signal is
generated. This can be used fo r narrow shift CW identification.
The CP-1 has been designed and tested to com ply with FCC rules
for a class-B com puting device under specifications outlined in part
15, subpart J.
The CP-1 is far better than the FCC requirements because of the
necessary close proxim ity of HF receiving equipment. To assure
maximum rejection of RF interference, be sure to use only well
shielded interface cables between the CP-1 and your com puter and
transceiver.
If com puter " hash" is present after using shielded cables, try
changing the physical location of the com puter and/or CP-1 relative to
the receiver. Under particularly d ifficu lt situations, try placing the
CP-1 and com puter on a different 110 VAC circuit from the one your
transceiver is using.
NOTE: To avoid interference with other electronic equipment in your
home or other's homes, make sure you make or procure cables which
are shielded, and have the shield connected to ground. AEASOFT™
software cables are recommended and have the needed shield.

RF SHIELDING

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