Project 1

Digital Interface

This digital interface kit was made and designed by Keith ZL1BQE as a club project for the Papakura Radio Club ZL1VK Branch 65. This project is run by David ZL1DK

Email.

Details and interest to build this kit can be addressed directly to David ZL1DK using the following link ZL1DK

Just click on his callsign above to email David.

Please make sure you read my Disclaimer and that you fully understand it.

This USB Interface unit designed by Keith ZL1BQE. It is powered up using the USB B socket on the front panel and is used for CAT control of the transceiver equipped with a USB audio system device so the TX and RX audio signals are accessible to the interface through the USB cable. RF isolation with AF transformers, Opto isolators to the PTT/FSK TX and RX with audio controls on the front panel. It also has on the rear, a CI-V interface for the Icom radios RS232 interface for the older radios. The kit comes complete with the case. The front and rear panels are actually circuit boards screen printed to give that proffessional finish appearence.

Assembly hints and tips

Before you start assembling this kit... First READ THE INSTRUCTIONS/TIPS below, they are there to help you.

For soldering tips, see Solder Basics

I recommend to use solder with 60/40 and 2% flux and to use a thin solder like 0.71mm when constructing this kit.

I recommended to install the three SMD IC's (surface mount components) FIRST... which are the U2, U3 and U5 IC's as these can be a challenge for some.

Installing these SMC IC's first allows you more or easy access as no other componets are in the way.

Using a thin solder makes it a lot easier when you are soldering surface mount componets so when applying solder you do not put too much on and you end up with a blob shorting out the pins or tracks on the SMD IC's. Just in case solder wick is also good practice to have on hand to remove any excess solder between the pins etc, depending on your soldering skills.

Install the resistors and make sure of the correct values. It is good practice to measure the resistor just to make sure you have the right components value you are about to install.

Next install the rest of the through hole IC's, capacitors working your way to the bigger components last.

You can use the photo of the completed version for reference only and due to some modifications made by Keith, your kit may vary slightly from mine. Photo 5 shows the later version kit.

Photo 1 shows the front of the interface

Photo 2 shows the rear of the interface

Photo 3 is the old version PCB of the kit's interface.

Photo 4 shows the interface kit fully assembled. You can also see in the photo, I have lined the inside case with tin foil. I also used a plastic lining to stop it shorting out. NOTE: This was an experiment only, trying to prevent RFI, when using the interface on HF. It was not proved that you needed to do this but if you were to experience any RFI on HF, make sure your leads connected to the interface are screened first. This is more likely to be the issue when experiencing RFI.

Photo 5 shows the new updated version of the interface kit. Also fully assembled. It now uses a RJ45 instead of the mini din (PS2) and some componets have changed. Also when I took this photo L2 and C29 are not yet installed. Other componets Y1 and Y3 and C19-C22 are NOT required if you have the CH340C version of SM IC's in your kit.

Photo 6 is the circuit diagram of the interface, designed by Keith ZL1BQE.