How To Do It
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[These instructions are based on the Matsui MR-4099. Control labels may differ on other versions.]
First, note down any frequencies you have stored in the receiver’s memories which you want to keep. The following process will wipe all memories.
Remove all the cells/batteries from the receiver, including the two AA-size memory backup cells.
Wait a few minutes.
[For the Matsui MR-4099]:-Set the DC power supply to negative centre on the output plug. If you are using one of the other receivers listed, check the manual or the DC power socket for polarity information.
Set the DC power supply to 4.5V output, and connect it to the mains electricity supply.
Plug the DC power supply’s output connector into the receiver’s DC IN 9V socket.
Press and hold down the LIGHT button on the top of the receiver.
Press the POWER button on the receiver. Keep holding down the LIGHT button!
Press the AM button on the receiver. The display should show ‘000KHz’. If not, try pressing AM or LW.
Press STORE, then one of the numbered buttons. You can now let go of the LIGHT button.
Turn the receiver over and insert 2 AA cells in the memory backup cells holder at the bottom of the battery compartment.
Disconnect the DC power supply from the receiver and set its output to 9V.
Connect the DC power supply to the receiver. Or :- Insert 6 ‘D’ cells.
Turn the receiver back on if necessary. The display should still show ‘000KHz’. If not, press CALL MEMO, then the button where you stored ‘000KHz’. If ‘000KHz’ fails to appear, try pressing AM or LW. When you do get ‘000KHz’ or a similar vlf frequency, put it in a memory straight away. If the receiver is unresponsive, is unuseably erratic, or refuses to tune VLF, disconnect the power and remove the AA cells for five minutes and try again.
If all went to plan…you can now tune VLF! You will notice a strong signal at 000KHZ. This is generated by the receiver’s tuning circuitry. Use the UP button to tune; pressing the DOWN button at any time will restore the receiver to normal operation, i.e. tuning will start at 150KHz. Pressing any of the waveband buttons, or the numbered buttons alone, will also terminate VLF operation. I do not know what effect the rotary tuning control will have on VLF operation – my own receiver’s rotary tuner was broken off earlier in its lifetime.
As you step through the KHz using the UP button, I suggest that you put some frequencies in the memory as you go. You can recall these frequencies and return to VLF, if you accidentally return the receiver to normal operation.
You will notice that the receiver behaves oddly. It may spontaneously re-tune itself to a different frequency, or initiate a scan. This is another good reason for putting vlf frequencies in memories. You will also likely see odd things displayed on the LCD readout. This is because the receiver’s ‘brain’ has been confused by operating at a low voltage. Do not worry! :-your radio is not damaged. You can restore it to normal operation by switching off, disconnecting the DC power supply/’D’ cells and AA cells, and waiting 5 minutes. (Sometimes longer).
CAUTION:- It is unwise to listen through headphones or earphones when there are loud bursts of static. I have permanent hearing damage in my right ear, due to ONE loud burst of static heard through one headphone. I was using stereo headphones, plugged into a mono socket, so only one ear got the blast. Fortunately not both.
In case you're wondering...holding down the LIGHT button is a simple way to put the PLL circuitry's supply voltage at just the right level for it to be sidetracked into VLF operation. In tests with the Matsui MR-4099, 3V was unreliable and the next setting on my DC power supply, 4.5V, made the PLL behave normally.
©2005 John Marsh