Custom Products for the Digital Radio Amateur Enthusiast
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Custom Products for the Digital Radio Amateur Enthusiast |
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What is it?
The DRA-SR-DIN6 gives you DRA sound card performance in the packaging of a SignaLink USB, along with a
Mini-DIN-6 radio connector. Our DRA-SR-RJ45 is the same thing with a RJ45 radio connector - just like
the SignaLink USB.
We've had some inquiries for a sound card device that has all of the cables on a common "side" and have the control functionality and a metal case like the SignaLink USB. I've also had some who purchased DRA-70s ask for adjustable VOX delay. A friend sent me a spare SignaLink USB and I used it as a pattern to make a retrofit circuit board that addresses some of the features people have requested.
Why are we making this thing?
We often hear that people are replacing their SignaLink's in favor of our DRA's. That's great, but
some people really like the way their SignaLink looks and feels, they just don't like how it works
with newer technologies like VARA FM Wide. It's existence is not meant to demean Tigertronics or their
products. With evolving technologies come evolving challenges. This was certainly a fun challenge, and
this series of DRAs has taken the most time and effort to design. Like all of our DRAs, its performance is
nothing short of amazing.
Who is it intended for?
This product is available to people who already own a SignaLink USB of older vintage and desires to upgrade
its performance. The circuit board simply replaces the original SignaLink USB board - - you reuse your
aluminum case, knobs, and end panels / screws - as is. You can restore your SignaLink to original
condition at any time. Using this board doesn't prevent you from putting your SignaLink USB back to
original condition. Under certain circumstances this product will work better, and may be better
mechanically suited for your operating situation - - as compared to our standard DRA Series offered
with an optional plastic case.
Other than Hardware PTT keying, there are no advantages to this board (that we're aware of) for lower speed applications like FLDIGI, VARA HF, or 1200 baud packet. It certainly has much greater audio bandwidth and higher transmit audio levels required by some radios for higher speed applications like VARA FM Wide and HS SoundModem. Hardware PTT operates independently from audio level, so you're never stuck between keying the radio and overdriving the transmitter.
What it isn't!
The DRA-SR-DIN-6 is NOT designed to be an exact replacement of your SignaLink USB! There are some
features and functions that aren't duplicated. It's not that we didn't think these
features are important, it's more about retaining performance. While we'd like to be able to include
every function, we believe it's more important to insure high-speed throughput, have very low USB noise,
and retain full-duplex performance (required for ASL and other duplex applications).
To emphasize,
the DRA-SR is not intended to replace the SignaLink USB for every installation or situation.
What's missing?
The SPKR, AUX, and MON functions and jacks are not present. Nothing occupies the original SPKR, AUX, and
MON holes. I couldn't put jacks there because of needing the board space for other circuitry, and routing
signals to these areas degrades the performance and elevates the USB noise. As such - if you need any of
these functions, this board isn't for you.
What's changed?
A female Mini-DIN-6 connector replaces the RJ45 radio connector.
It just so happens that the physical dimensions of the DIN-6 female connector are very close to the RJ45.
This change was done mainly because the RJ45 jack used on the SignaLink USB is not shielded, but the
Mini-DIN-6 jack is. This change prohibits the use of the original SignaLink radio cables, but, it doesn't
make it any harder to interface than any other DRA. If you want the capability of reusing your original
SignaLink USB radio cables, you should consider the
DRA-SR-RJ45 model.
The DRA-SR Series doesn't use transformers. This does come at the cost of galvanic isolation and RFI resistance. The DRA-SR is NOT galvanically isolated. While the audio paths are decoupled by large electrolytic capacitors and the PTT uses a relay, all signal paths return to a common ground. The necessity and practicality of galvanic isolation are commonly debated. We feel grounding and bonding can be as effective. A very high quality USB cable with ferrite RFI reduction is supplied with all DRA-SR's. This cable provides additional RFI protection.
What's the same?
Several parts, like the power switch and panel mounted pots
are from the same manufacturer that Tigertronics uses. This allows the SignaLink's plastic end
panels to be reused without modification. Power (Green/Amber) and PTT (Red) LEDs come out their original
holes on the front panel. The power switch functions just like the original, however the DRA-SR has a white
cap (button) instead of red. This is one way to tell a SignaLink USB has been retrofitted with
the Masters Communications board. Like all DRA's, the Power LED is also the heartbeat (HB) indicator.
A mechanical jumper configures the Power LED to flash or be on solid. You can expect the same performance from
this model as compared to any other DRA.
What's the design based on?
The DRA-SR Series is based upon our top-shelf DRA-80. Unlike our other VOX capable DRA's, this board
includes a VOX delay control that's located in the same position as the original delay pot (DLY) - on
the front panel. The delay range is from 0 to 1.5 seconds. The VOX gain control (R16) is not accessible
from the outside, but most people just turn this pot up pretty far anyway. Of course, the DRA-SR has both
Hardware PTT and VOX keying of the transmitter. VOX operation is configurable with jumpers just like the
DRA-70 and '80, and can be (should be) disabled when using Hardware PTT preventing any possible VOX delay.
What led up to its design?
The desire to keep people from throwing away their SignaLinks... I'm not exaggerating! Plus - it's a great
packaging system - why not reuse it? Many hours were spent routing traces, and positioning
components to keep the controls and LEDs in their original locations. The challenge was to achieve the
performance of our DRA Series while retaining as many original SignaLink USB features as possible. While
we've successfully achieved the performance of our other DRA's, unfortunately, the MON, AUX and SPKR jacks
had to go to maintain the highest speed and retain the high signal-to-noise ratio found in
our other DRA's.
Okay - really - how good is it?
The DRA-SR Series actually beats all other amplified DRAs in having the lowest noise. If you're looking for the
ultimate FT4 or FT8 interface, this is it. Plus - it goes as fast as any other DRA easily reaching Level 13 in VARA
FM Wide (licensed) with any high-speed data capable ham radio.
Pro's & Con's
Summary:
To order - you must acknowledge that you have read and understand and agree to the terms and conditions, limitations, and usefulness (or lack there of) of this product.
If you agree and want to continue, check the box below to be given the link to place the order.
Email Kevin Custer for support of this exciting product.
Product of Masters Communications, all rights reserved.
SignaLink™ and SignaLink USB™ are trademarks of
Tigertronics.
The use of the name SignaLink and/or SignaLink USB is only in reference to this product.
No infringement for such use is intended.
Specifications may change without notice.
Images are property of Kevin Custer - W3KKC
Board layout by Kevin Custer - W3KKC
HTML June 26 2021, W3KKC All Rights Reserved!