Friday, September 11, 2015

Digital Interface Link4 by BD7JAD

A few months ago, I decided to buy radio interface for digital operation from BD7JAD.
The interface is known as LINK4. It is used for radio CAT interface and digital communication such as SSTV, RTTY, JT65, Echolink, CW etc.. this operation is software dependent.. you need to use the right software for the application and LINK4 does PC-RIG communication. It has USB port (connected to PC), a 9 pin connector (for DATA, CAT & PTT), TX & RX audio level potentiometer and headphone/line out socket at the rear. For the front, it has 4 LED  to indicate PWR, PTT, CW & CAT.

It is a very well built device, powder coated metal casing and a professionally assembled PCB with built in USB isolator. The isolation transformer is no longer used in LINK4.

From the picture below, you can see a wire and extra socket which I added as a modification to activate PTT using foot switch.
The reason I did such modification is because I plan to use it as interface for SSB communication using Voice Shaper to process the audio before transmitting. This means, I will be using a microphone connected to the PC and Voice Shaper will do the compression for SSB operation.

To know more about Voice Shaper, you can see HERE

Overall, I like the LINK4 but I found some minor fault.
1. It can pickup sound (such as knocking on the case) and you can actually hear it if you configure the PC built in sound card to "listen" on the C-Media line in. C-Media is the built in sound card on LINK4. I am not sure if it also have similar issue on the C-Media line out which will actually the audio line out to your rig.
2. USB communication suffers from glitch and hanged if the rig & antenna is not properly grounded. I solved this issue by adding a snap in ferrite core on the USB cable and proper grounding of radio.

Nevertheless, I personally think the issues described is minor and can be solved easily without affecting your operation.

If you are thinking to get one, go ahead and try it yourself.


Wei Ee, Ying said...

Hi there 9W2DTR,

I tried finding your email but to no avail. I'm keen on manufacturing with CNC routing, but can't seem to find any reliable services. Do you happen to know any?


9M2PJU said...

voice shaper ni aku pernah test tapi tak best sangat tapi boleh la pakai dengan radio standard. tengok souncard jugak. kos pun murah tak macam hardware dari w2ihy tu gila mahal. cuba try pakai mic yang sedap sikit dengan sound card external jenis firewire atau usb3.0 tu mesti best. Cmedia yang link4 rasanya sama dengan link2. bunyi knocking on the case tu rut kata biasa. aku pun confuse pasal apa ada bunyi tu. link2 pun macam tu jugak tapi rasanya tak masuk ke audio line ke rig bila aku test playing audio untuk auto cq guna n1mm. aku monitor kat rig.