Notwithstanding the range of 500 to 1000 Hz deviation for subaudible tones stated in TIA-603C, most modern radios are capable of reliably detecting CTCSS and CDCSS modulation when deviated as low as 100 Hz. I usually set subaudible deviation to around 400 Hz, especially for stations used in the Amateur service. This level seems to work 100% of the time, and it prevents repeater talk-off caused by CTCSS distortion when a very loud voice is limited in the transmit audio circuitry. Also, since many less-expensive radios do not have subaudible tone filters in the receive chain, the users seldom can hear the tone.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of nj902 Sent: Friday, December 12, 2008 1:16 PM To: [email protected] Subject: [Repeater-Builder] Re: MSF-5000 PL encode deviation The original factory design specification for the MSF5000 PL deviation is 800 Hz. That is just slightly greater than the 750 Hz. mid point in the acceptable range of 500 Hz to 1000 Hz as given in TIA-603. One issue that can cause the PL level to be incorrect is failure to properly perform the modulation compensation alignment. This often gets overlooked and is required when moving the station to a considerably different frequency than the one it was operating on when the initial alignment was performed. ------------------------------------------------------ --- In [email protected] <mailto:Repeater-Builder%40yahoogroups.com> , "Ralph Hogan" <rhog...@...> wrote: "... Have an MSF-5000 repeater we're trying to get going on VHF. ... Have noticed the PL encode deviation is a little high at about 900 Hz. ..."
