Doug Hall Electronics

RBI-1

Hints & Kinks

For additional hints, questions, etc. you may wish to contact DHE direct. I have found Duane Hall to be most helpful in providing additional information. The company also makes an excellent four-channel voter (I have one) that is expandable.

Remember, join the RLC remailer and share your ideas with other controller owners. This is an open list not sponsored by any company and not limited to Link Communications equipment. You may also want to check out the Link Communications sponsored re-mailer at http://www.link-comm.com.

Feel free to e-mail your hints and thoughts to me.

I prefer good thoughts but bad are OK also.


Use a Doug Hall Electronics RBI-1 Remote Base Interface? Wondering what radio is compatible with the RBI-1? They are here!

Don't have an RBI-1. You should buy one! Can't afford an RBI-1? Want to use an old BCD programmable transceiver? Want to know which radios use BCD programming? This is a partial list. If you know of others, please send e-mail so that they may be added to the list.

Having problems with the audio? Read on - - -

I am using the RBI-1 and have modified the unit as follows to improve the remote base transmit audio on my Micor / RLC-3 combo.

1. Remove C5. This is the capacitor at the rear center of the PC Board just above the top of U6. This is the 5821 IC that controls the user functions. Replace the capacitor with a 1uf unit of 15 volts or higher.

2. Remove C16 and/or C17. These are .01uf capacitors and they are located between C5 and U3, an LM324. C17 is the one closest to C5. In my unit I only removed C16 and C5. If you wish to have even more high frequency response then you should remove C17 also.


Using multiple transceivers on your RBI-1?

When I first installed my RBI-1 I was using two Kenwood's, one on two meters and one on 220. Things worked great until I installed two additional transceivers for 440 and 1.2 GHz. I then found I had lost my TX audio. I have since found several other users that have experienced the same problem. Duane at DHE was eager to help with troubleshooting things.

It appeared that when installing three or more transceivers the audio is loaded down. If intermixing models, it is possible for the audio line to be shunted to ground by the mute circuitry in some of the radios (TM-x41 series) when the radio is powered off remotely with the RBI-1.

Now for the FIX! Very simple, simply add a 2.7K ohm or anything close in value in series with the audio to the transceiver. A 1/4-watt will fit but an 8th or smaller is much easier to install.

Disassemble the 8-pin microphone plug and place the resistor in series with the wire going to pin one of the plug. You will have to crank up the audio level a bit to compensate for the add resistance. This is VR-1 on the left rear of the RBI-1. Turn it clockwise (it's a ten turn trim pot) until the desired TX audio level is achieved. That's it! I have had no further problems and recommend the RBI-1 without reservation.


The only problem you may have is with locating Kenwood transceivers, as some are no longer in production. If you are looking for a unit, send me mail and I will put you on the list as I occasionally come across some used units a very reasonable price.

For a list of compatible transceivers, CLICK HERE.


 Not happy with the receive audio from your Kenwood to the controller?

The RBI-1 uses unprocessed audio from the Kenwood radio.

The Kenwood radio has an IC that is the second mixer IF and detector. The audio is taken from pin 14 of this IC and it goes through a 1uf capacitor with a 1K-ohm resistor in series and then to pin 6 of the microphone connector. In order for this audio to sound good you will have to add de-emphasis.

In the case of the RLC-3, simply turn on switch #1 for whatever port you have the remote connected. In other controllers you may have to either connect or remove a jumper.

If your controller has no provision for de-emphasis you can make your own passive network with a couple of resistors and a capacitor. Go to the RLC@onelist.com or ACC@onelist.com and voice you need for good audio. Chris Boone, WB5ITT belongs to both of these remailers and is the "Audio Guru". He can tell you how to modify your controller for flat audio or anything in between. If Chris can't solve your audio problems - no one can!


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 Last update 11/02/98