Custom Products from Masters Communications

Overview of the latest REV5:
1, EEPROM and CM119A is supplied pre-installed on all kits.
2, Access to all GPIO from circuit board 'lands' marked G1 through G8.
3, Bias resistors for Q1 and Q3 - see below.
4, PSEL option (preconfigured for a ground - see below).
5, VSEL option (preconfigured for an open - see below).
6, Kits come with the surface-mount ICs preinstalled.

The PSEL and VSEL options are only required for proper operation of the CM119 (without the A suffix) or the CM108. All REV2 and beyond boards are shipped with CM119A chips, and PSEL and VSEL are preconfigured for normal operation and won't require any jumpers or other attention.

Q1 and Q3 are 2N2222 bipolar transistors. The prototype used FETs in these locations but I felt the bipolar was a better fit. The FETs didn't require bias resistors and is why R22 and R23 were added to the REV2 circuit board to accommodate the 2N2222 bipolar junction transistor.

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-35. Choose this option from our PayPal ordering drop-down. See below.

Installation:
This device is intended to be installed inside a radio, computer, or project 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.

H1 and H2 header pin assignments:
Click here for a detailed header pin explanation. The primary purpose of the headers H1 and H2 are for installation of optional FL-10 audio filters. The FL-10 is designed to be installed onto the header pins directly or remotely by extending the four pins with wires. Jumpers are needed over the center two pins if the optional filters are not installed.

Recommended powering requirements:
The board is supplied with 5 VDC from the USB connection. The audio amplifiers and optional filters can run from this, or from an external power source of 6 to 15 VDC. Jumper JU2 controls where the voltage is sourced from.

Recommended receive audio input level:
The RA-35 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. As little as 20 mV P-P can be used with a setting of rxboost=1, and as much as 20 volts P-P with a setting of rxboost=0. If your receive audio level is adjustable or programmable (like in a Kenwood TKR-750), we recommend around 2.0 volts P-P and a rxboost=0 setting. 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 REV2 and beyond production boards are supplied with a Genuine C-Media CM119A.

The REV2 board (and all boards since) are designed to be versatile. Some Prototype RA-35s used a CM119 (no suffix) while most were supplied with a CM119A. A CM108 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.

Information on interfacing the RA-35 to a Kenwood TKR-750/850 repeater.
Click here for programing recommendations and wiring/hook-up instructions.

Secure PayPal ordering available from the main RA-35 page.

Custom radio cables are available from URI Cables. They will build a custom cable for the RA-35 for many radios.

Third Party Compatible Projects:
MABEL is an interface and software that allows analog control of the Yaesu DR-1X repeater and access to the AllStar VOIP network with the Raspberry Pi3 and AllStar Asterisk. (Offsite Link)

Email Kevin Custer for ordering information, ordering by check, and/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 November 27, 2016, W3KKC All Rights Reserved!