Model airplane news: Guide to micro R/C receivers

Model Airplane News, Nov 1999 by Aberle, Bob

This combination of Hitec transmitter and tunable RF module would prove especially helpful for indoor, backyard or parking-lot fliers because non-interfering channels could more easily be selected. You would only need a few extra receiver crystals (check with your receiver manufacturer for cross-brand crystal compatibility. Think about it!

Sky Hooks & Rigging's SNR-RX72

Now we are getting into the really small, almost "ultra" micro receivers. This one is manufactured by Tom McCann of Oakville, Ontario, Canada, and it weighs just 0.07 ounce (2g); that's 1/10 ounce! Its light weight matches its size: just 1x 1/2x5/16 inch. This tiny receiver appears to be nothing more than four JST connectors and a postage-stamp-size circuit board. It is available on 72MHz R/C channels and operates on FM. This particular model has 4-channel control capability. It is compatible with JR, Airtronics, Multiplex, Hitec and Futaba R/C transmitters. The selectivity claim is /- 76KHz, and that makes it broadband-definitely not narrowband. So when flying, you will have to block out several frequency clips on either side of your operating channel. The claimed radio range is 1,000 feet, which is more than enough to fly both indoors and in schoolyards. Again, since JST connectors are employed, you had better check the polarity before you attempt to connect any servos. In a recent phone conversation, Tom mentioned that his receivers have been certified to comply with the new FCC regulations.

Critters Bits CB-4FM

This is a tiny receiver of single-conversion circuitry that claims excellent performance at a very attractive price. The only challenge so far has been getting the Far East supplier to actually produce these units in sufficient quantities to meet the demand. The Critter Bits receiver comes in a plastic case that measures 1 1/16x7/8 x9/16 inch and weighs 0.28 ounce (8g). Removing the case could further reduce the weight and size. Connectors employed are conventional, but no instructions were provided concerning connector polarity. Four-channel control functions are provided. The receiver operates on FM from both Futaba and Hitec transmitters on 72Mhz frequencies.

Selectivity is claimed to be very narrow at around 10KHz, and the stated range is on the order of 750 feet.

Sky Hooks & Riggings RX72 H (Hybrid)

This is an SHR-RX72 micro receiver to which an integral 4A electric-motor speed control has been added. All of the features of the SHR-RX72 receiver are included. The speed control will allow from 6 to 10.5V input. The BEC provides 5 volts at 0.8 amps. A microprocessor will not permit engine startup unless at low throttle. It will also stop the motor on loss of radio signal. The Hybrid ESC does not shut off the motor when the voltage drops below 5.3 volts, but it does reduce the amount of full throttle available to a maximum of half throttle. Weight of this combined receiver and ESC is only 0.14 ounce (4g), and the dimensions are 1x3/4x5/16 inch. JST connectors are employed, and the receiver has 4-channel functions One of the four JST connectors goes to the motorbattery pack.