I've been designing a multi-channel aviation receiver, with amazing sensitivity, selectivity, audio quality and overall usability. The following list shows my design goals for this project, which I'm now calling SCARP, until some better naming thought comes along:
I'm in the process of finishing up a whitepaper on how this little radio scanner was designed. Would you like a free copy?
First and foremost, SCARP was to be an aviation receiver. Any added feature will help, not hinder this design goal.
The sensitivity of the unit had to be exceptionally good.
The audio quality must be without compromise – crisp, clear audio reception.
Squelch would be perfect and automatic, with very limited or no user interaction required.
In keeping with SWaP principles, (Size, Weight and Power) the Size should allow a product to be offered which would be the same size (or smaller) than other aircraft receivers or transceivers. Weight would also be very low, and Power requirements would allow multi-hour usage on rechargeable batteries.
It must be capable of stand-alone operation. (This means it doesn’t need to be hooked up to another device to function, such as a computer or iPhone.)
AND, conversely, it must have a mode where it can be remotely controlled, via a serial or USB channel. This would allow use case models where my new SCARP technology might be controlled by another computer. An example would be an open avionics design for experimental aviation, where the receiver (this product) is controlled by a cool user interface in a panel computer.
I wanted it to support multi-channel scanning. Practically speaking, this means that when one channel (for instance, the tower) is being received, that is what you hear. As soon as that channel ceases, SCARP must be able to determine that it is no longer active and move on to another channel within a few milliseconds.
I also insisted on being able to tune in increments of as little as one hertz. The practical implementation of this allows tuning on 25khz or 8.333 khz channel spacing.
I wanted to include the creativity of the Maker community in my work. This would help get better UI’s faster, and provide something to the Maker community which doesn’t really exist: a receiver that is easy to program for, uses an Arduino, and provides features similar to, if not superior to, far more expensive and complex Software Defined Radios. (Inexpensive SDR radios do not have the sensitivity, selectivity or ease of use of my SCARP.)
How about low cost? While listed last, that was one of the first things I focused on.
BTW, this video shows operation of SCARP with a diminutive 3" antenna. SCARP still works very well, even though challenged with a very inadequate antenna. Other future SCARP videos demonstrate different antennas and prove how well it works.
P.S., our kickstarter will commence soon. Sign up for early bird stuff via the link in the video.