Custom Products from Masters Communications
|
Custom Products from Masters Communications |
|
Support Documentation
for
Model RA-25K
Top side of RA-25K circuit board - shown slightly enlarged.
(Click photo to show a larger image)
Bottom side of RA-25K circuit board - shown slightly enlarged.
(Click photo to show a larger image)
Schematic Image - Click to download a high quality PDF.
Overview of RA-25K
1, Use with VARA FM or other digital communications requiring a quality sound card.
2, DB9 pinout compatible with Kantronics KPC series TNCs.
3, Kits come with the surface-mount IC preinstalled.
If you purchased our kit, refer to the parts list and make sure you have all of the components
you need to build it.
Click here
for Parts List.
Construction/Assembly:
Click here for assembly instructions and construction notes - with large photo.
Optional Plastic Case:
A Plastic Case is available optionally for the RA-25K.
Choose this option from our PayPal ordering drop-down. See below.
A case can be 3D-printed
from these free files - designed by Richard Bateman KD7BBC
Installation:
This device is intended to be installed inside a radio, computer, or plastic box for protection.
Refer to the schematic for the pinout of the DB9F where all of the logic signals, power
connections, and audio signals are listed.
Click here
for DB9, jumpers and other board connection assignments.
Recommended powering requirements:
The board is supplied with 5 VDC from the USB connection.
Recommended receive audio input level:
The RA-25K accepts the widest range of audio compared to any other similar radio adapter. The
input signal is attenuated by a potentiometer, giving the broadest range of acceptable levels.
If your receive audio level is adjustable or programmable,
we recommend around 2.0 volts P-P. This allows very good signal-to-noise
ratio and low cabling cross talk. This level results in a 50% rotational setting of the potentiometer.
Which C-Media chipset is used?
All DRA series radio adapter boards are supplied with a Genuine C-Media CM119A.
The PC board was designed to be versatile. A CM108 and CM119 is also acceptable. There are slight differences between these components, and the board can be 'programmed' to accept any of the three.
Information on the CM119A.
Click here
to download a manual for the C-Media CM119A.
Information on the CM119.
Click here
to download a manual for the C-Media CM119.
Custom radio cables are available from URI Cables. They will build a custom cable for the RA-25K for many radios.
Email Kevin
Custer for support, ordering information, order by check, or support of this
exciting product.
Product of Masters Communications, all rights reserved.
Specifications may change without notice.
Images property of Kevin Custer - W3KKC
Board layout by Kevin Custer - W3KKC.
HTML January 14, 2020, W3KKC All Rights Reserved!