Acom International 1000 Manual do utilizador - Página 11

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Exhibit 8

11 -17

Please note also, that the TRI mark will not appear until at least 5W drive is applied, and at least 20W forward power is

achieved.

If, for some reason, matching cannot be accomplished successfully, check BAND switch and antenna selection. Then

check the antenna VSWR at same drive frequency.

d) Tuning hints.

While turning knobs, you'll note that both tunings would be virtually independent. This is a benefit of the TRI. The plate-load resistance increases to the

right and decreases to the left of the TRI center.

The center of the scale corresponds to the proper LOAD capacitor tuning, which presents an optimum load resistance to the tube.

If you tune to the right, you'll obtain more gain, but less undistorted output power will be attainable. You may prefer to use this hint when your drive

power is insufficient or when you need less output but better efficiency, for instance at heavy duty modes (RTTY, SSTV etc) where less heat is

wanted.

Tuning to the left of the center would lead to the opposite: less gain and more power attainable. Of course, this requires more drive power, more plate

current, and more plate heat, which shortens tube's-expected life, as its cathode would be faster exhausted.

You might use the off-center tuning hint also to compensate for mains voltage variations in order to maintain tube

efficiency: tune to the right when mains is higher, or tune to the left if it's lower than the nominal voltage. Please see S.2-

2 (Line Voltage Selection) for more than 10% difference from the nominal.

4-4 ON LINE Information Screens and Control Functions.

a) Besides the Warming Up and TRI (described above in S.4-1 through S.4-3), you have 12 more

Information screens available. They are as follows: Forward Power, Reflected Power, Output Power (difference between

forward and reflected), Antenna VSWR, Drive RF Power, RF Power Gain, Plate Current, High Voltage, Plate RF Peak,

Screen Current, DC Power Input (product of plate current and high voltage), and Exhaust Air Temperature (Celsius and

Fahrenheit scales). You can use them to monitor the technical state of the amplifier and the associated parameters in

digital form.

Selection is made by the PREV and NEXT buttons. You may change them in a closed loop, while the amplifier is used

and controlled in operate and standby modes, changes transmit and receive, without any influence by the measuring

process.

b) You can control LCD adjustment and Auto-Operate feature selection also while ON LINE.

The method is the same as it is described for OFF LINE, so see S.5-1 and S.5-2 for

details.

4-5 Auto-Protection System

When any abnormal condition is detected, the amplifier will evaluate the risk and may use three different degrees of

protection, depending on the nature of the problem. Each event is accompanied by a text telling you the reason. The

backlight of the LCD is flashed meanwhile in order to attract the operator's attention.

a) The first degree of protection is issuing a warning message only, without any influence on the transmitting process.

This might be for instance "Reduce Drive", "Plate Current", etc. You could continue to transmit under such conditions but

you are close to a trip threshold.

b) The second degree of protection is a trip in standby mode (Soft Fault). You'll get an appropriate message, for

instance ** GRID CURRENT **. All Soft-Fault messages are marked with two asterisks on both screen edges. The

message remains on the display until you press any button (or auto-operate function returns to operate mode

automatically). The Soft Faults are of such kind where you can correct exploitation conditions operatively (using less

drive, improving VSWR, etc).

c) The third degree of protection is a trip in off mode (Auto-Protection).

You'll get the corresponding signature (see S.6-5 - Troubleshooting). If you cannot guess what is the reason, you may

try to turn the amplifier on again in order to check whether it's not an accidental condition. If the problem persists, you'll

need to contact your dealer - see S.1-2.

NOTE

The 6dB input attenuator is automatically inserted about 1 second after a bad tuning is detected at drive levels above

20W. It is switched off at every PTT release (unless inserted manually).

5. OFF LINE OPERATION

There are two control functions and 14 information screens available in this state of the amplifier. You can control the

LCD contrast and backlighting or enable/disable the Auto-Operate feature. You can also list the auto - protection

signatures. The tube is not powered at all (only the micro-controller is active) during these operations.