Scale Ship Modeler's Association

When thinking about breakthroughs in Radio Control technology, quite a few things come to mind.  From the first electronic speed control, dual throttle control, first computerized radio, and first synthesized radio, there have been a number of milestones. ISM band, or 2.4GHz Spread Spectrum Technology can now be added to the major milestone list. 

(cue the Victory at Sea music) The Industrial, Scientific and Medical (ISM) radio bands are reserved internationally for industrial, scientific and medical purposes other than communications. In general, communications equipment must accept any interference generated by ISM equipment.  ISM devices are designed for unlicensed operation, so they need to be tolerant of interference from the multitude of other devices also using the ISM band.  I've heard it argued that 2.4GHZ won't work well near large bodies of water.  In practice, that couldn't be further from the truth.

For many people, the most commonly encountered ISM device is the home microwave oven, wireless LANs, and cordless phones. Add to that Bluetooth.  Because unlicensed devices already are required to be tolerant of ISM emissions in these bands, unlicensed low power devices are generally able to operate without causing problems for other ISM devices.

How does it work?  Simply put, your receiver hears any transmitter in range, but ignores all but your transmitter.  When the transmitter is energized, it listens for other transmitters and simply chooses an unoccupied channel.  The receiver is  bound to its transmitter so it will obey only THAT transmitter.  Bonding is a simple process that takes about 10 seconds.  Yes, you can bind multiple receivers to one transmitter.  I apologize in advance to the geeks among us who need more detail.  I've read some spirited discussions (RCGroups.com) on what is actually happening under the hood on these radios, but much of it beyond this knuckle dragger. Google is your friend.

To review, this is what you get with your ISM gear.

·  No crystals

·  No frequency board.

·  No transmitter impound.

·  Unlimited receivers to one transmitter. Think about it-  potentially 1 transmitter for an entire fleet.

·  No range issues.  Get out of range, you better have video.

·  No frequency collisions ever.  

·  No usage exclusive to air or surface. You could hold a regatta and a fly simultaneously in at the same venue.

·  No external receive antenna needed.

·  6 inch ducky transmit antenna.  Goodbye the swordplay.

The receivers look fairly typical, except for the antenna length is much shorter.  You might even see 2 of them.  There is no need to run them up a tube or even outside the hull at all.  Just keep it out of the way.  If there are 2, you should anchor them in opposite directions.  Unfortunately, ISM is not for submarines.  2.4GHZ won't penetrate even fresh water more than a few millimeters.

I can't seem to keep up with what is now on the market.  Everyone making radios should be in ISM by now.  EWS has a 4 channel system at Tower Hobbies for about $50.  As more inventory hits, it might drive the price down even more.  Shop carefully, but with most surface applications, you can't go wrong.

We boaters are once again reaping the technological benefits sowed by our flying and surface racing brethren.  However, our control requirements are trivial compared to theirs.  Propagation delays or loss of signal of a few milliseconds can cause an aircraft to auger in, a boat to flip, or a car to hit the wall.  Some aircraft and helicopters also require some processing and mixing of inputs.  Us?  Forward, backward, left, right, on, off.   What this means is that, with the ISM technology, radio issues will now be rare to non-existent.