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Technical Support

This page generates programming instructions for RAK-2 and RCS series systems that have firmware version 6 in the embedded RFC-1. Users of earlier models, including RAK-1 systems and stand-alone RFC-1 systems, should use the programming pages that are compatible with those models.

Program an Indirect Power Channel

A telemetry channel can be setup to give an indirect power reading. In this mode the channel does not give a reading based on its telemetry input but instead calculates a reading based on the two channels before it. Those two channels must read the plate voltage and plate current respectively.

For example, to calculate an indirect power reading on channel 03, channel 01 must read the plate voltage and channel 02 must read the plate current.

The settings for the indirect power reading are stored in the same memory locations that normally assign a unit word, scale and decimal to the channel. Special calculations are required to generate the correct settings.

This page simulates the behavior of the indirect power operation of the RFC-1/B with reasonable accuracy. Since it is a simulation there are cases where it does not respond exactly like the actual processor. The discrepancies are minimal.

Calculation

The telemetry value for the indirect power channel is calculated from the equation: POWER = (VOLTAGE * CURRENT * EFFICIENCY * SCALE)/10,000,000

  • VOLTAGE is the plate voltage in volts
  • CURRENT is the plate current in amps
  • EFFICIENCY is the system efficiency
  • SCALE is a multiplier used to adjust the result into the correct scale

Efficiency

Efficiency values greater than 100% can be used to compute effective radiated power (ERP) as opposed to transmitter output power (TPO). This value can also be adjusted so that the power calculation results in a percentage of authorized power.

Example

If an antenna has a gain of 6.5, the feedline has an efficiency of 75% and the transmitter has an efficiency of 72%, the overall efficiency (input power-to-ERP) is 6.5 * 0.75 * 0.72 = 3.51.

In this example, to compute the actual ERP the efficiency value should be 351%–the decimal is dropped. If transmitter power output (TPO) is to be computed, the efficiency should be programmed to 72%.

The efficiency value can also be adjusted so the computed reading is a percentage of authorized power. In that case, the efficiency resulting from the above formula should be multiplied by 100 and then divided by the normal transmitter output power in kilowatts. The goal is for the reading to be "100.0" at 100% of authorized power.

Instructions

Use the selections below to program an indirect power channel. All items must be completed.

The values and adresses will be calculated and displayed. Click the "Show Instructions" button to display step-by-step programming instructions.

Plate Voltage

This is the typical plate voltage reading in volts–not kilovolts. Use up to four significant digits. Ignore the decimal but keep the digits that follow the decimal.

enter plate voltage in volts

Plate Current

This is the typical plate current reading in amps. Use up to four significant digits. Ignore the decimal but keep the digits that follow the decimal.

enter plate voltage in amps

Efficiency

This is the system efficiency value. Use up to four significant digits. Ignore the decimal but keep the digits that follow the decimal.

% enter efficiency value

Scale

This value forces the reading into an appropriate scale to maximize the resolution of the reading.

Start with 10 and calculate the result. If it is not acceptable then adjust the multiplier up or down accordingly. The result must be less than 9999 to be valid.

set the scale multiplier

Channel Number

This is the channel to program. Indirect power cannot be assigned to channel 00 or channel 01.

select a channel from the list

Unit Word

This sets the unit word that will be spoken after the power reading.

select an item from the list

Decimal Position

This sets the decimal point in the power reading.

select an item from the list

Results

The indirect power reading will be:  

Click the "Calculate" button to update the results.

Program these addresses with the values shown below.

At memory address: program value:

At memory address: program value:

At memory address: program value:

At memory address: program value:

Programming Instructions

Programming instructions are displayed in a new window. Popup blockers may interfere with this feature.

Notes

Requirements

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Programming

Section 6 of the RFC-1/B manual describes the use of programming mode. A brief tutorial is also available.

The programming address table in the manual provides a list of all the memory address and their functions.

Step-by-Step

To simplify programming, this page can generate step by step programming instructions.

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