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MFJ 434B DRU

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k4lrx:



For some time I have owned this unit and have found it a welcome addition to the ham shack. If your rig does not have a DRU this will certainly save your vocal chords during a contest, or during those big DX pile-ups.

My former rig, a Kenwood Ts 950 SDX I had for fifteen years did have a DRU as an extra-added feature in the radio. However, the unit had noticeable bit noise in the audio and although it was not noticed by on air checks, I found it to be a little annoying.

Working in the broadcast profession for forty-five years my ears detect audio problems such as peak clipping on ssb, or bit noise in this case. I also found the Kenwood DRU to have problems such as losing memory, only noise on the recordings and constantly having to check to see if indeed it was going to work in a pile up.

The Kenwood unit had only three message storage selections and the time of the message was very short.

I had contacted Kenwood on this problem and their only solution was replace the entire card for over two hundred dollars. To me, this was not an option I wanted; yet I did want the DRU in my operation.

In fact, Kenwood could not guarantee they could provide a replacement unit, seems like the product support falls off after a unit is ten years old or older. Enter MFJ, I looked over their unit and I was impressed, first of all five message storage selections all twenty seconds or longer.

I decided to order this unit and give it a try on my rigs to see how it worked.

Once you receive the 434 you are instructed to configure it for your radio, Icom, Yaesu, or Kenwood. You remove the top, remove, or add the provided jumper plugs, but wait you may have to adjust one more thing so leave that cover off for now.

The microphone input on the unit is the standard eight pin, so now if you have a  the mentioned rigs, plug your microphone in the DRU and start recording your messages. The instruction book will guide you through the process, but it is quite simple. Depress the record button, grab your microphone and then depress the message button of your choice. Depress the message button when finished, you can use the internal Microphone on the DRU. It is not the greatest, but does have good quality; the choice is yours as to what microphone you wish to use.

The provided cable connects to your radio and you are in business. You recall I mentioned the additional adjustment needed. Well, this is audio level input to the recording chip. I would suggest connecting your rig to a dummy load while making the adjustments to the DRU.
To suit the audio of your radio it may take a few minutes and some adjustment of the input and output controls on the DRU. You will need a small screwdriver, or a plastic alignment tool with a metal blade on the end for adjustment of the two controls.

MFJ suggests placing the internal control at mid range and then adjusting the output control found on the rear of the unit for best audio. You want to adjust the audio so that it does not have the over driven sound, or distortion.

You also want this level the same as your microphone level, so this may take a little time to get it right, but once done, set and forget.

I have filled all five-message slots, for one I have my call phonetically for DX expeditions, message two a signal report followed by my call letters. The remaining slots are for contest exchanges, namely sweep stakes or DX contests.

You can repeat the same message over and over based on the time selected, you have one control plus a stepper switch that expands or decreases the time between each announcement.

You do have a monitor speaker, it is not the greatest for fidelity, but it is not bad, you do have a volume control on the front panel to control the level. The 434 does require twelve volts to run it, you have the choice of buying the power cube from MFJ at $17.00 or some rigs have a twelve volt port in the rear of the radio. In my case I used the twelve-volt port and saved my self $17.00.

MFJ also offers a remote attachment for $34.95 if you are an ingenious person you can make your own since all it requires is a contact closure. It is your choice the remote plugs into the rear of the 434.

I would suggest in setting up the audio from the DRU you use your monitor in the rig and if possible listen to your transmitted signal on another receiver. If nothing else get an air check from a friend. The DRU is well shielded and isolated from RF, so this will not be a problem.

The new price is $199.95 plus any extras you might need. Not bad at all and this unit works and sounds good for what it is intended.

If any questions feel free to drop me a line… Bill, K4LRX

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