RDG Products Throughout the Years: The Retro Technology That Made Us
We've been in the custom engineering world for over thirty years, and we've learned a thing or two about wireless communication technology. Here's a look at some of the custom-engineered solutions from the RDG archive!
Paging Simulation Software (PES-PC)
In the early 90s, paging was very popular. Cellphones were expensive, both to purchase and use, and battery life was incredibly limited. Pagers could last for a month on one battery, and the monthly fee was very affordable.
At the time, RDG had several projects designing pagers in one form or another. One thing they all had in common: they needed a way to be tested. Most companies in the paging business had custom test systems that they designed in-house, but no one made an integrated paging test system at the time.
We developed a pager test system using a combination of PC software and a simple hardware adapter to create the paging signal. Coupled with an FM capable RF generator, the PES-PC pager test system could handle testing for a fraction of the cost of a custom piece of equipment. Instead of spending thousands of dollars, the entire system was less than $400.00.
Though simple by today’s standards, the PES-PC did the job well, and was easy to use, as well as being versatile, as the “intelligent” part of the system was done as software on a PC, rather than on a custom piece of hardware.
Voice Organizer Pager
Who remembers the PDA? Back in the '90s, before smartphones, Personal Digital Assistants were all the rage. The Voice Organizer Pager used advanced voice recognition that allowed talk-to-text! RDG added paging capability, making it even more useful. You could find ads for those things in every in-flight magazine (remember in-flight magazines?).
Originally, the Voice Organizer had no paging capability. When improved memory chips with more capacity in smaller footprints became available, there was space to add a paging receiver. However, there was not a lot of space, and most pager designs took up too much space to fit inside the already cramped quarters of the Voice Organizer.
With our compact, single chip receiver design for the 900 MHz paging band, adding paging to the voice organizer became possible. The units sold well at outlets like Radio Shack (remember Radio Shack?) until advancements in cellular technology made pagers essentially obsolete.
Other Pager Designs
While we haven't done a pager design in a while (like this one here in the ad), the techniques are still useful for a wide variety of receivers, both for voice and data.
Paging receivers are basically the same as other data receivers but optimized for long battery life. This is accomplished using highly integrated designs that save power, as well as a system that allows the receiver to remain in sleep mode for the majority of the time. The data rate is typically slow (9600 BPS is typically the top end), which also helps conserve energy.
Radio Design Group designed several pagers during the early 90’s, including a very compact pager for Phillips, as well as a credit card style pager, shown in the ad to the left.
Swatch pager watch
The Swatch pager watch combined an analog movement (you know, the kind with "hands") with our groundbreaking single-chip receiver for 900 MHz, making the small form factor possible. Until Radio Design Group developed this design, the highest frequency a single chip design could achieve was slightly over 500 MHz. With the new 900 MHz design, the watch pager was able to incorporate not only the watch movement, but also a digital display that showed the phone number of the person sending the page.
Up to that point, pagers used receivers made from a large number of discrete components, making them impractical to fit in a wristwatch. Our single chip design for 900 MHz was unique in the industry, and its small size was key in leaving room for the actual watch movement. Another example of how we were able to create the impossible for our customers!
GEMS Klaxon Pager
One of our most interesting projects was a pager/klaxon system for the DoD. The wirelessly triggered system was able to withstand a severe electromagnetic pulse (EMP) event, like a nuclear weapon. The klaxon was used in the ready room or other common areas, while the pagers were meant to be worn by key personnel.
It was a challenge on several fronts: it required a small RF bandwidth, so we used an enhanced narrowband technology that we had developed. It also needed to operate over a wide temperature range, so we made sure to pay careful attention to thermal issues. Most importantly, it had to continue functioning after an EMP event.
During development, we got a call from the test engineer telling us that everything was great, except that flames had shot out of the power switch during one test! After some additional circuit changes, all went well!
SOS Phone
Back when cellular phones cost a lot of money to buy, and even more money to use, a client came to us with a novel idea: a pre-paid phone designed primarily for emergency use. By keeping the device and its service simple, the cost to the consumer would be substantially reduced, and so, the SOS phone was born.
Even though it was an analog phone (using FM to send the voice, rather than digital modulation) the RF technology it contained was quite advanced for its time, with much higher levels of integration than most other cell phones of the day. Simple, yet cutting edge, the phone became popular, and filled an important need while the market waited for the cost of using a cellphone to come within reach of the average consumer.
GSM Sentry
In the early days of digital cellular systems, small remote cell sites were used for “fill-in” coverage. Those sites were not always completely reliable, so we developed the GSM Sentry, a GSM (Global Standard for Mobile) data device that reported on the health of the cell site to which it was attached and would use an adjacent site to send a failure message (via text message) back to the network operations center if needed. The unit was completely self-contained, and even had its own battery backup system in case of a cell site power failure. An early form of IOT, long before IOT became a thing, circa 2002!
1980s Call Box
Back in the day, when cell phones were rare, motorists could get stranded for hours on the road waiting for help. Los Angeles had a callbox system on major freeways, but running telephone cables along roads was too expensive for most areas. So, they turned to wireless as the best solution.
However, there was a problem. Callboxes in L.A. spent up to an hour on hold as just ten operators managed incoming calls. Meanwhile, hundreds of other calls were waiting in line! Wireless systems couldn't handle the overload.
The game-changer was "virtual hold." Instead of keeping callers on hold, the system disconnected them but retained their information. When operators were available, the connection was automatically re-established. This saved tons of radio channels and made callboxes practical!
Fuel tank remote reporting system Barton Instruments
Sometimes clients come to us with a request to make a good product better. This was a sophisticated fuel tank level monitoring system, and in the middle of the board is a wireless data transmitter. Range was limited in the original design. We added several improvements to improve the range, making the unit even more versatile!
MVSK
Sometimes prototypes get fairly complicated. MVSK (m-ary variable shift keying) provides a high-speed, very jam-resistant, and very secure data path that works in adverse conditions. MVSK was developed in response to the need for highly secure, jam resistant communications for flight termination systems. The unique design of the MVSK waveform makes it inherently secure, as well as highly interference resistant. Here's a prototype of an MVSK receiver we designed circa 2005. If you have a need for secure, jam-resistant communications, contact us to see if MVSK will work for your application.
1997 Advanced Architectures
AM/FM radio plugged into computer as a card
Back in 1997, a client came to us with the idea to build a complete AM-FM-Shortwave radio in an EISA (Extended Industry Standard Architecture) bus card for PCs.
Before digital streaming, this allowed computer users to listen to their favorite radio station right on their computer. The interface was windows-based, making it easy to use, as well as light on processor power to run. Audio was output directly to the computer sound system as an analog signal.
Like most technology, changing standards eventually made it obsolete, but it was an important step towards how we listen to the "radio" from our computers today!
While some of these inventions are now obsolete, we're incredibly proud of our place in communication tech history. We're not done yet! Contact us today to find out how we can help you create the impossible for your RF communications project!