Custom Products for the Digital Radio Amateur Enthusiast
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Custom Products for the Digital Radio Amateur Enthusiast |
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Looking for radio adapters for AllStar Link applications? See our original
RA-Series.
Quick Description:
What are they?
DRA Series interfaces are radio optimized sound cards used to connect a two-way radio to a computer
(or host) for digital data communications with Amateur Radio.
What are they used for?
The DRA-Series interfaces are used for Packet Radio
and/or other digital programs and applications that use Linux, MAC OS, or Windows®.
A DRA can be used with software packages which include, but are not
limited to:
VARA HF, VARA FM, VARA FM Wide, VarAC, and VARA CHAT
SoundModem and High-Speed (HS) SoundModem
fldigi
AFSK and GSM Packet Radio
ARDOP
Winmor
PSK (all of the flavors)
In addition, there are other software programs that require a VOX capable DRA. Our DRA-65, '70, '80, 100,
and SR Series additionally have VOX. The latter two additionally have a VOX delay control.
These programs include:
FT4/8 with WSJT-X
MMSSTV and YONIQ
The DRA Series digital radio adapters are the result of re-engineering the original and very successful RA Series AllStar Link radio adapters with digital communications and installations in mind. Like the RA Series, these DRA's are high quality - high-performance. Some models are quite inexpensive, and price doesn't necessarily dictate the speed or transfer rate. All DRA's are capable of the fastest throughputs, because, for the most part, the radio is the determining factor of which one to buy.
A sound card interface (with the appropriate software) can replace many hardware based devices like a Kantronics TNC or other more expensive modems. You can do it all with just the appropriate software and the right DRA connected to your rig.
Detailed Description
For those willing to continue reading.
The DRA Series digital USB radio interfaces have several featutures and advantages over other radio
interface offerings, so I'll explain in detail what they are.
Status LEDs
There are three differently colored LEDs for status:
Power / Heartbeat Monitor - Green LED:
The green LED illuminates solid when the DRA device is plugged into a USB port of the host computer and is
being powered. All DRAs include a Heartbeat Monitor. When the software is running, you will see the
green LED flash. If the green LED unexpectedly stops flashing - the application has
quit streaming audio, or, the DRA or computer/appliance has failed, stopped, or crashed. How fast the
green LED flashes is determined by the application. Some programs flash the green LED faster then others.
COMM OK - Blue LED:
If everything is running okay, (green LED is flashing) a Blue LED called "COMM OK" illuminates solidly. If
the green LED stops flashing because the radio adapter or the computer/appliance has failed, or the software
has stopped or crashed, the Blue LED goes out. The Blue LED indicates the status
of the system, and illuminates solidly when everything is okay. This Watchdog Timer affects two
functions. Read about them further down in the detailed explanation.
PTT Circuitry - Red LED:
All DRA Series digital radio adapter interfaces include solid-state (silent) switching for Push To Talk
(PTT). A Red LED illuminates anytime PTT is active and keying the radio. The DRA-52, '80, 'SR and '100
models use a reed relay to allow some rigs to key up properly. The operation of the relay is nearly silent.
The DRA-65/70/80/100/SR also inculude VOX PTT.
Radio Connectors:
The DRA-30/45/65 use a DB9 female radio connector that has the same pinout as many Kantronics
TNCs allowing for easy transition from this old technology to a DRA for much faster speeds. The DRA-34
and DRA-54 have a RJ45 female radio connector. The DRA-39 is compatible with radio cables
built for a SignaLink® USB. The DRA-36, '50, '52, '70, '80, 'SR-DIN6 and '100-DIN6 have a Mini-DIN-6
female radio connector for easy connection to radios that have a matching 6-Pin Mini-DIN data connector.
There are two 3-pin mechanical header/jumpers on all DIN6 models to select between the 1200/9600
receiver audio sources.
USB Connector:
On every DRA, the host connector is a USB-B female. A USB A to B (printer type - M-M) cable is
normally supplied to connect the DRA to the computer. The DRA normally gets all of its power through
the USB connection. A sepatrate power source is not required.
Quartz Crystal Stability:
All DRA Series radio interfaces include a 12 MHz quartz crystal for optimum temperature and
operating stability.
Genuine C-Media CM119A:
All DRA Series radio adapter interfaces include a geniune CM119A chipset for best digital transfer
performance.
Audio Input (from receiver):
All of our radio interfaces have a potentiometer audio input
attenuator (the large one), allowing for the finest adjustment of receiver input audio level. As such,
the DRA Series provides for the widest range of receiver audio levels. The goal was to be
compatible with just about any radio or situation out there, where the amount of receive audio
feeding the CM119A is concerned. Since audio levels are 'calibrated' in software the user
has the ability to optimize the audio input level assuring the best signal-to-noise ratio
and the lowest distortion. R12 on all DRA's adjusts the receive audio level.
Audio Outputs (to transmitter):
The DRA-30/34/36 don't include amplification of the TX audio paths. These interfaces are intended
where lower levels of TX audio is sufficient. Many ICOM radios don't require the elevated audio
of our amplified DRA's, nor does any radio that will be fed transmitter audio
through its MIC jack.
The DRA-45/50/52/54/65/70/80, DRA-SR and DRA-100 come with two audio amplifiers on board. The objective of this design is to have enough audio to drive a FM modulator directly, or any load impedance - even a speaker. We wanted to make sure these interfaces had enough transmit audio capability for any radio. Yes - they can be reduced in level to work with radios that don't require all of that transmit audio.
Manual Transmitter Audio Level Control:
Some Windows software allows control of the transmit audio level by settings - some don't.
As such, all DRA-Series radio adapters have manual controls (the two small pots) for adjustment.
The controls are not always necessary, but they are included on all models as
a matter of convenience. They're necessary for applications that don't include sufficient
software alignment, and, to fine tune the audio levels even when the software levels can be
controlled. R14 and R16 control the transmit audio levels on all DRA's.
Audio Coupling (to transmitter):
All DRA series radio adapters have large coupling capacitors providing plenty of audio with the
ability to drive a low impedance. In the case of the DRA-45/50/52/54/70/80/SR and DRA-100,
even a speaker. Of course,
the amount of audio that is available is also dependent on the software settings. This allows
the user to choose the right amount of audio to feed their transmitter, insuring the best
signal-to-noise ratio and the least amount of distortion. There are no transformers in the DRA's which
can degrade audio performance.
Logic Inputs and headers/jumpers to disable them:
All DRA Series radio adapters use the CM119A IC. It has logic inputs which were originally intended for
Windows Volume Settings. These inputs were adapted for AllStar Link for COS and CTCSS logic inputs.
As of this writing, these inputs are not needed for VARA or any other Windows digital program.
In fact, if something is connected to the COS and CTCSS (Windows® Volume UP and DOWN pins) bad things
can happen. In addition, DCD (XDC) and/or other logic or control
lines might be connected in existing installations using the KPC-3 or similar TNC.
These functions are disabled for Windows programs
by removing "JU" jumpers specified for each radio adapter. As such, even if
these inputs are tied back to the radio somehow, it won't matter - their existence won't affect the
operation of the DRA for Windows digital applications. These jumpers could be reinstalled
if there's ever a need for them; restoring the DRA to the same capability -
functionality as a RA Series. Plus, these hardware inputs may be implemented sometime in software -
permitting DCD or some other digital feature, so we didn't want to limit the hardware
from using them in the future. Of course, installing these jumpers restores
the AllStar Link functionality, and allow you to use these adapters with that
technology.
General Purpose Inputs and Outputs (GPIO):
All DRA Series radio interfaces include GPIO support. GPIO buffer circuitry takes up a lot of real estate.
Since space is limited in a small package like this, there just isn't enough room to buffer
everything - especially with all of the additional circuitry for the improvements we've incorporated.
Since you cannot really drive anything directly from a GPIO pin, and other interfacing circuitry would be
required to use these pins, we decided to skip any additional buffering. The GPIO
pins are brought out to small circular solder pads for connection as you see fit.
PTT Keying for Handhelds and Portables:
The DRA-30 includes two locations for an optional keying resistor. A resistor is sometimes
necessary to key handhelds/portables into transmit. This resistor is not supplied, and is usually around
2k ohm resistance, when required. Since there are two audio outputs, one resistor location is used
for each of the two TX audio outputs. R-PTT 1 and R-PTT 2 are for the primary and secondary audio
outputs respectively. R-PTT 1 is the resistor for TX audio on DB9 pin 1, and R-PTT 2 is for TX
audio on DB9 pin 8. No other DRA includes this feature - just the DRA-30. Portable radios don't
require a lot of audio, and therefore the optional keying resistors aren't included on other models.
"COMM OK" Detailed Explanation:
The COMM OK watchdog 'health' status is established for two reasons:
First and most importantly, the PTT line on any DRA Series radio interface is interrupted
with the failure of this health status. A valid PTT cannot be asserted unless the Blue LED is lit.
If the Blue LED is out, the PTT line is disabled, and the RED LED will not illuminate.
No more inconvenient trips to the radio site to kill a stuck transmitter.
This circuitry was designed to operate correctly no matter if the Heartbeat
has stuck in the on or off state. This function prevents a stuck PTT and is beneficial in
unattended operations.
Secondly, on the DRA-45/50, the logic developed at DB9 pin 7 (or "LC - local control" on the DRA-50) (user-selectable, none, high or low - with header jumper JU1) can enable a secondary control method, or be tied to an alarm. Many times digital communications is co-located with repeaters, and this output can be tied to a repeater controller or other apparatus that can be used to signal a problem remotely. The DRA-50 has similar logic, but there's no room for it in the Mini-DIN connector. The logic is available at hole on the circuit board marked "LC" near the Mini-DIN connector. Only the DRA-45 and 50 include this feature.
Board Dimensions:
All DRA Series radio interfaces (except SR and '100) have simple rectangular circuit board dimensions of 1.8 X 3.8 inches (1-13/16" X 3-13/16").
Note this is just the dimensions of the board only. The tallest components are the large output coupling
capacitors which stand a little less than .625 inches (5/8") tall including the thickness of the board. The dimensions
for the finished product, including the additional length of the connectors, are 1.8 X 4.5 inches
(1-13/16" X 4-1/2"), and the height remains unchanged. The 1/8" mounting holes are separated by 1.56 inches
(1-9/16") on the short sides and 3.56 inches (3-9/16") on the long sides, and are a simple rectangle.
Other Options:
The DRAC-12 - 6-foot Mini-DIN-6 Radio Cable can be added optionally
to connect your Mini-DIN-6 equipped radio to a DRA-36, DRA-50, DRA-70, and the new DRA-80.
The Mini-DIN-6 radio connector adapter can be added optionally to the
DRA-Series to convert the DB9 radio connector to Mini-DIN-6 female.
The SPKR-4 - 3-foot 1/8" Speaker Cable can be added
optionally to connect your DRA-39, DRA-SR-RJ45 or DRA-100-RJ45 receive audio from the radios speaker jack.
The RJ45-6 radio connector adapter can be added
optionally to the DB9 equipped DRA's to convert the DB9 fermale radio connector to RJ45 female.
The VOX-10 Voice (DATA) Activated PTT adapter can
be added optionally to the DRA-45 to provide VOX keying.
The Alinco-6 radio connector adapter
used on the Alinco DR-x35 series single band radios to convert the DB9 radio connector to Mini-DIN-6 female.
The RA/DRA-Case can be added optionally to any of the
DRA Series radio adapters (except 'SR and '100) to protect it. It's a nice snap together plastic case. Choose
from several available colors!
Click here for detailed features list and adapter comparison.
DRA-30 Low-Cost High-Quality
digital USB radio adapter with a DB9 radio connector.
DRA-34 Similar to the DRA-30 but
with a RJ45 radio connector.
DRA-36 Similar to the DRA-30 but
with a Mini-DIN-6 radio connector.
DRA-39 Similar to the DRA-30 but
with a RJ45 radio connector and a configuration socket for using SignaLink radio cables.
DRA-45 High-Quality
digital USB radio adapter with TX audio amplifiers and a DB9 radio connector.
DRA-50 Similar to the DRA-45 but
with a Mini-DIN-6 radio connector.
DRA-52 Similar to the DRA-50 but
with a relay for keying some ICOM radios like the ICOM IC-706MKIIG and ID-880H.
DRA-54 Similar to the DRA-50 but
with a RJ45 radio connector.
DRA-65 Similar to the DRA-45 but
with VOX keying.
DRA-70 Similar to the DRA-65 but
with a Mini-DIN-6 radio connector.
DRA-80 Similar to the DRA-70 but
with a relay for keying some ICOM radios like the ICOM IC-706MKIIG and ID-880H.
DRA-100 Similar to the DRA-80 but
has VOX delay and an all aluminum case.
DRA-SR Intended for those who
already own a SignaLink® USB and want to change it to DRA functionality and performance.
Custom cables available from URI Cables. They can build a custom cable for the DRA Series radio adapters for many radios.
So what's different between the RA and DRA Series?
Go Here to read all about it.
Email Kevin Custer for ordering information, ordering by check, and/or support of these exciting products.
Products of Masters Communications, all rights reserved.
Specifications may change without notice.
Images are property of Kevin Custer - W3KKC
Board layouts by Kevin Custer - W3KKC
HTML February 3, 2020, W3KKC All Rights Reserved!