CALIBRATION / EQUALIZATION
26
Calibration / Equalization
The CALIBRATE command is used to assist the TNC operator in determining the need for equaliza-
tion of a received signal. Since this feature is unique to Kantronics TNCs, two stations using
Kantronics TNCs are necessary to utilize this command.
KAM you must have your current I/O stream on the VHF radio port.
KPC-4 uses current I/O port (will not work with an external modem.)
KPC-2 The HF, HFT and CCITT commands should be OFF. Calibration is checked at 1200 baud only.
KPC-1 Tones are transmitted and received at the HBAUD setting and the frequency is specified by
the HF and HFT command settings.
KPC-2400 Tones are transmitted and received at the HBAUD setting and the frequency is specified
by the HF, HFT and CCITT command settings. However, calibration cannot be done at the HBAUD
setting of 2400.
Once the CALIBRATE command is given, three options will appear on he terminal screen:
Calibrate Mode Press R,T, or X
Pressing X will return the TNC to the Command Mode.
Pressing T will transmit a square wave (space/mark) at the selected tones until a key is pressed.
Pressing R will measure a square wave received.
One station should be used to transmit the square wave, while the receiving station should mea-
sure and compare the space/mark square wave. The transmitting station should set the micro-
phone level in mid range.
Once the receiving TNC is placed in the CALIBRATE receive mode, two numbers will appear on the
screen. The TNC is measuring the the space/mark square wave generated by the transmitting sta-
tion. For the best calibration of the receiving transceiver, set the radio tone controls so that the
two given values are as close to equal as possible.
In most instances when the ratio of the numbers is within a 40/60 or 60/40 range, the Packet sta-
tion will function normally. A larger disparity in the tones may cause additional retries during
Packet operation. This ratio may be determined by the following formula:
(N1 × 100) / (N1 + N2) where N1 is the number to the left of the displayed slash and N2 is to the
right of the slash. For instance, if the TNC displays 1400/1800, the ratio can determined by:
(1400 × 100) / (1400 + 1800) or 140000/3200 = 44
Since the total is 100, the ratio is then 44/56 and is within the 40/60 criteria.
KPC-1, KPC-2 and KPC-2400. If the ratio of the numbers exceeds 60/40, you should change the
setting of the equalization command (EQUALIZE). Use the setting (ON or OFF) which results in the
ratio closest to 50/50.
KAM and KPC-4. If the ratio of the numbers exceeds 60/40, you should reset the internal Equaliza-
tion jumper(s) for partial equalization. If, with partial equalization these numbers are still outside
the 60/40 ratio, set the Equalization jumper for NO equalization.
To Next Page
Loading...
