Summary
A maker's manual for its rack-mounted venue FM transmitters at 72 MHz and 216 MHz: channels, power, antennas, cable loss, channel selection for several transmitters, compatibility with other brands and the regulatory notices.
Key findings
- Gives 72.025-75.950 MHz with 17 wideband and 40 narrowband channels and a field strength of 80,000 µV at 3 m for the 72 MHz model, and 216.025-216.9875 MHz with 19 wideband and 38 narrowband channels at 100 mW, "max allowed by FCC", for the 216 MHz model; system frequency response is 50 Hz-15 kHz at 72 MHz and 50 Hz-10 kHz at 216 MHz.
- Says choosing an interference-free channel is "trial and error": with transmitters off, listen on the receivers to each wideband channel and pick the quietest.
- Says at most six transmitters work at once in the same space at 72 MHz and three at 216 MHz, recommends adjacent channels at least 300 kHz apart and names a recommended channel set for each band; transmitters spread over a large area can use adjacent channels if the adjacent-channel transmitter is at least 50% further from the receiver than its own.
- Advises the lowest power setting when several transmitters share an environment and full power otherwise, locking the chosen channel, mounting the antenna high and vertical, away from metal, and keeping coaxial cable short; it gives RG-58 losses of about 4 dB per 100 ft at 72 MHz and 8 dB per 100 ft at 216 MHz, and notes that a portable receiver's headset cord is its antenna.
- Describes 72 MHz as "a secondary frequency band" where paging and other licensed transmitters can interfere, and 216 MHz as "a primary frequency band" on which "no other types of transmissions are authorized", while warning that a nearby TV channel 13 transmitter can cause intermodulation, in which case it suggests switching to 72 MHz.
- Its FCC statement says the 216 MHz transmitter is authorised under the Low Power Radio Service (Part 95), needs no licence, must not interfere with TV reception or the Air Force Space Surveillance System at 216.88-217.08 MHz, and may be used only for auditory assistance, health care, law enforcement tracking or AMTS control; its Canadian statement repeats the channel 13 test and the advice to use a channel near 217 MHz.
- Says its SQ noise reduction works only with its own SQ receivers and must be switched off for other makers' or older receivers, gives cross-reference tables to other brands' channel numbers, and warns that some other makers' receivers may distort with its +25 kHz deviation.
- Recommends lower-loss RG-8 antenna cable rather than RG-58, and setting each transmitter to its lowest output power that covers the area, to reduce the possibility of interference.
- The specification table on printed page 3 labels its system figures as wireless end-to-end: frequency response ±3 dB, total harmonic distortion below 2% at 80% deviation, and A-weighted signal-to-noise ratio of 80 dB with SQ enabled for LT-800, versus 60 dB at 72 MHz or 50 dB at 216 MHz with SQ disabled. The separate architectural paragraph gives a 63 Hz lower frequency limit, while the table gives 50 Hz.
Limits
A manufacturer's manual for its own products, without measurements. Its description of 216 MHz as reserved is narrower than the FCC and Canadian rules, which share the band with other uses, and its specification table lists FCC Part 90 for the 216 MHz model while its FCC statement cites Part 95. The date is from the file name of the version linked from the product page (version A4, 3 November 2025); the printed footer still reads 17 June 2024, version A3.
Read the original
www.listentech.com/wp-content/uploads/2021/01/LT-800_803-User-Manual-2025-11-03-vA4-WEB.pdf
Cited in
- How many receivers and neckloops does each code require, and how should a loan pool be run?Partly answered
- Which radio bands can venue FM and RF systems use, and what limits them?Partly answered
- How good is the sound each system delivers: bandwidth, codecs and speech understanding?Partly answered
Cite this source
Listen Technologies. User Manual: LT-800-072, LT-803-072 and LT-800-216 Stationary RF Transmitters. 3 November 2025. https://www.listentech.com/wp-content/uploads/2021/01/LT-800_803-User-Manual-2025-11-03-vA4-WEB.pdf (accessed 13 October 2026).
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