13
12.8 Sparks / Discharges in RF area
Very high RF voltages are present in the amplifier during the operation at high power. Incursion of dust or even suicidal insects can
cause such temporary problems.
12.9 SWR cut-off
The factory adjustment for SWR protection is about 2.6: 1. This adjustment can be changed, but the best is to operate with a properly
matched antenna. Should your DX-2 'see' bad SWR, it will shut down for 3 seconds (in bypass mode).
12.10 Frequent over-drive protection cut-off
As previously described in the tuning and operation sections, there is a protection acting on DX-2 input overdrive. When the drive
reaches the limit where signal distortion begins to occur, the overdrive indicator on the front panel will warn you to reduce the drive. If
you increase the drive even further, a cut-off protection is activated.
After about 2 seconds of amplifier bypass, the operation is resumed, but if you have not reduced the drive, the protection will be
activated again. To stop it, you must reduce the input power drive. This protection is not adjustable, you must not exceed the limit. If
this happens too often, you obviously do not have a fine control over the transmit level of your transceiver. In this case, try using the
ALC, See section 10.2.
12.11 Tube replacement
It is very unlikely that you will ever need to replace the GU84B. If there is a need for that, the tube is easy to replace, but a bias
adjustment is required for the new tube. See the service section of this manual.
13 WARRANTY I SERVICE
The full FOUR YEARS warranty for DX-2 amplifiers covers all parts and labour, except for the tube. The tube is under a limited
warranty, also for FOUR YEARS.
14 GLOSSARY
AC Alternating Current
ALC Automatic Level Control
AM Amplitude Modulation
CW Continuous Wave
DC Direct Current
EBS Electronic Bias Switch
FM Frequency Modulation
HF High Frequency
LED Light Emitting Diode
PEP Peak Envelope Power
RF Radio Frequency
RTTY Radio Tele Type
SSB Single Side Band
SSTV Slow Scan Tele Vision
SWR Standing Wave Ratio
VAC Volts, Alternating Current
VDC Volts, Direct Current
WARC World Administrative Radio-communications Conference
VSWR Voltage Standing Wave Ratio
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