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Picture: Gary Poland - W8PU
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Picture: JM CHERRY
MODEL 4-LF LOW FREQUENCY CONVERTER INSTRUCTIONS
DESCRIPTION
The Model 4-LF consists of a highly stable solid state crystal oscillator mixer, and low pass filter. When plugged into the crystal calibrator socket on the DRAKE 2-B or 2-C or the accessory socket of the DRAKE 4-Line Receiver, it converts incoming signals between 500 - 2000 KHz to the ten meter bands of the receivers. The range may be extended by using other accessory crystals in your receiver. 1.2 The 4-LF is intended as a simple and inexpensive device for receiving relatively strong signals below 2.0 MHz on your DRAKE receiver. It, therefore, does not have any tuned input circuits and cross modulation may occur from strong, adjacent signals. Adjusting the converter antenna length will usually reduce any cross talk to an acceptable level. In severe cases, a simple tuned circuit designed for the specific frequency used can be added to the antenna input.
INSTALLATION
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Remove the 4-LF from its carton and insert it in the crystal calibrator socket of the 2-B or 2-C or the accessory socket of the R-4B.
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Disconnect the antenna from the receiver terminal. (Failure to do this will result in the reception of both the low frequency and the 10 meter signals simultaneously.)
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Connect a long wire antenna to the 4-LF antenna terminal.
OPERATION
The receiver controls should be set in the manner prescribed in the instruction book for the desired mode of operation. An improvement in signal to noise ratio will usually be obtained by reducing the RF Gain control setting and increasing the AF Gain.
Paragraph 4.0 illustrates the proper bands on the receiver for the desired frequency coverage.
The “on-off” switch on the converter should be placed in the “off” position when not in use. If left on, the receiver sensitivity is reduced when used for normal operation.
FREQUENCY COVERAGE
| Desired Receiver Frequency Range | Required Receiver Accessory Crystal | 4-Line | 2-C / 2-B |
| 0 - .5 MHz | 27.5 -28.0 MHz | 38.6 | 24.0 |
| .5 - 1.0 MHz | 28.0 - 28.5 MHz | 39.1 | 24.5 |
| 1.0 - 1.5 MHz | 28.5 - 29.6 MHz | 39.6* | 25.0* |
| 1.5 - 2.0 MHz | 29.0 - 29.5 MHz | 40.1 | 25.5 / 25.6 |
| 2.0 - 2.5 MHz | 29.5 - 30.0 MHz | 40.6 | 26.0 |
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* Furnished as standard in receiver |
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