Allstar Link Node Build - Part 2

Welcome to part 2 of my Allstar Link project build. Before I continue I would like to take the opportunity to wish everyone around the world a happy, healthy and prosperous 2021.

Wiring up the Baofeng BF-888s

The next few steps involve adding various cables to the radio in preparation for making connections to the power supply and CM108 USB sound module. I used different coloured cables to make it easier to identify the various connection points.  First connect a short length of yellow cable (aprox 20cm) for the COS.

  

COS is an acronym for "Carrier Operated Signal" , "Carrier Operated Squelch" , or "Carrier Operated Switch".

 

 

Transmit PTT Input

Connect a short length of blue cable (aprox 20cm) for the transmit push to talk line (PTT) as shown in the next image .

Power supply Input

Connect a short length of red cable (aprox 20cm) for the main radio positive power supply feed. Also connect a Black cable for the negative power feed/ground as shown.

 

Audio input and output

Connect two screened audio cables (aprox 20cm in length) for the transmit and receive audio signals. I used a thin screened audio cable salvaged from a computer CD Rom drive.  Other guides on the internet do not use screened cable for the audio signals & I consider this bad practice!

 

 

Secondary power supply Input

Connect a a short length of orange cable (aprox 20cm) to the PCB and a 100nF capacitor as shown in the next image. The additional power feed to the radio's RF output stage will permit some experimentation later on!

 

 

Tidying up the wiring

All of the connecting wires are now in place and I have secured them together with a nylon cable tie.  The yellow, blue and two screened cables are trimmed to a length of 15cm measured from the bottom edge of the PCB.  Finally they are terminated into a 6 way Molex connector.

 

 

A clean break

The next step involves making a break to a PCB track, the image below shows the location of the PCB track to be cut away, I used a fine craft knife for the job but you could also do this with a small drill bit. You may be wondering why I have cut the PCB track! All will be revealed soon in a further blog post.

 

 

Battery connector removal

It is time to mount the radio PCB back on to the alloy chassis. Before doing this unscrew & remove the battery connector from the chassis and make sure the small heat-sink pad is still in place!

 

Final Step

To complete the work on the Baofeng radio transceiver it is time to mount the PCB back on to the alloy chassis. Secure the PCB in place with the 3 screws as indicated in the following image.

The preparation of the Baofeng radio transceiver is now complete and in the next installment I will start work on preparing the CM108 USB sound card.

Until next time... 

 

73's From Andy G6LBQ

Its all About The Radio Ga Ga...