Equipment Review
Decade MS-100s Certified FM Transmitter
Decade Transmitters - Sherbrooke, Quebec, Canada
HobbyBroadcaster.net Product Lab Review video of the
Decade MS-100s Part 15 Certified FM Stereo Transmitter.
We have had many requests for an evaluation of the Decade line of FM stereo transmitters. Thanks to Decade's Vice President, Sylvain Couture, we were loaned an MS-100s Stereo FM transmitter for our lab evaluation and testing.
Opening The Box:The Decade MS-100s came well packed as it was delivered via Fedex. The first thing we noticed is that the transmitter had some substantial weight. The steel metal case was such a welcomed feature compared to some of the plastic cases of the less expensive units. Along with the transmitter is the familiar "wall wart" power supply and an audio adapter that converts the rear mounted three conductor 1/4" phone jack to dual phono ("RCA" type) jacks.
The MS-100 series transmitter is offered in four different configurations: mono unbalanced line-level input, mono balanced line-level input, mono microphone-level input and stereo unbalanced line-level input.
The exterior of the transmitter has two LED indicators for power (green) and over-modulation (red). An input level control has a nice sized control knob and the actual control has a study feel when compared to the budget-grade transmitters. The rear of the transmitter has the input jacks for both the power and audio adapters as well as a heavy duty telescopic whip. The rear chassis has an access hole to allow changing the transmitter's broadcast frequency as well as enabling the bass boost circuit and, on stereo-equipped models, a switch to enable or disable the onboard stereo generator.
The Inside Story:The quality of the transmitter is quite evident when you open the unit up. A high quality circuit board that is silk-screened for easy sub-system and component identification.
Don't expect the typical ultra-cheap BA1404-chip based stereo generator circuit with mediocre sound quality. About half of the transmitter's circuit board is dedicated to the stereo generator circuitry while the remainder contains the frequency generation, modulation and output circuitry. Board construction utilizes thru-hole components as well as dual inline package (DIP) integrated circuits. It was noted that at least three integrated circuits, U2 in the RF section and U17 and U18 in the stereo generator are intentionally obscured by sanding the tops of the chips. While it is presumed that this is done to provide "trade secret" confidentiality, this removes the possibility of any user serviceability in the field.
Fire It Up:We prepared for the tests by selecting an open available frequency in our area. Something unique to the Decade transmitter is that the manual contains a chart to guide the user to adjust the length of the on-board telescopic antenna to an appropriate length based on the transmit frequency. I was quite impressed that somebody had bothered to take this into consideration when designing and certifying a Part 15 FM transmitter. Pages 6 and 7 of the manual include the chart to aid in frequency tuning via the DIP switches on the rear of the transmitter. This chart is also imprinted on the bottom of the transmitter case. Page 11 of the manual includes the table of antenna length adjustment measurements.
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