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-RJ45 gives you DRA sound card performance in the packaging of a SignaLink USB, retianing the
RJ45 radio connector and reusing your existing cables and jumper modules - but with a few limitations
explained in detail below.
Who is it intended for?
This product is available to people who already own a SignaLink™ USB of any 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, cables and modules - 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 a Signalink or our standard DRA Series offered with an
optional plastic case.
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. Its 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.
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-RJ45 is NOT designed to be an exact replacement of your SignaLink USB! There are some
features and functions that aren't duplicated on this retro board. It's not that we didn't think these
features are important, it's more about retaining performance and available space. While we'd like to be
able to duplicate 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 in every installation or
situation.
What's missing?
Units shipped after November 15, 2022 are (REV2) and include a 3D printed rear panel with a 1/8" (3.5mm)
speaker jack, however the AUX, and MON functions and jacks are not duplicated. 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 the AUX or MON functions, this board wont work for you.
What's changed?
The DRA-SR Series doesn't use transformers. This does come at the cost
of NO galvanic isolation. 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 is commonly
debated. We feel grounding and bonding can be as effective as isolation, and it's safer. If galvanic
isolation is something you aren't willing to give up, then use a USB isolator. 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?
The DRA-SR-RJ45 has the same RJ45 radio connector as the SignaLink USB. This allows you to reuse your
existing Signalink radio cables and "Plug-&-Play" jumper modules or the supplied jumper
wires. 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
panles to be reused without modification. Power (Amber/Green) 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 standard DRA's with VOX, the SR board
includes a VOX delay control, and it's 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. VOX 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, and has many radio cable options available - why not reuse them? A friend sent
me a spare SignaLink USB and I used it as a pattern to make a retrofit DRA circuit board that addresses
some of the features people have requested. 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 and
AUX jacks had to go to obtain 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 October 26 2021, W3KKC All Rights Reserved!