Kevin Custer wrote:
> I have to interject here...
>
> Gregg R. Lengling wrote:
>
>> Using tones below 60 Hz usually doesn't work for 2 reasons. #1 reason
>> is that the transmitter will not reproduce that low of a tone without
>> distortion
>
>
>
> Your statement Gregg that "the' transmitter will not reproduce that low
> of a tone without distortion" is generalizing that all repeater
> transmitters are incapable of response below 60 Hz. I have tested many
> repeater transmitters and can verify that 'most' station exciters that
> employ FM modulation will easily do 33 Hz at standard PL deviation
> levels. These include the PLL Mastr II, FM Micor, Mitrek, MSR-2000,
> Hamtronics synthesized PLL, and certainly many more modern repeaters
> that are synthesized.
>
>> and overdriving....
>
>
>
> ?? Explain your use of the term overdriving in your statement.
>
>> and the receiver audio won't recover it.
>
>
>
> Huh? Receivers that can do DPL can easily detect a 33 Hz PL tone, and I
> don't know of any receiver I have ever tested that wouldn't receive a
> DPL properly from the discriminator. a 33 cycle PL tone at 750 Hz
> transmitted deviation isn't a problem for the receiver to recover.
>
>> #2 the lower the frequency the longer it takes to decode.....I
>> realize it's not a great amount of time difference with todays uP
>> decoders but it is still slower.
In fact, DPL "turn-off code" is 34 hz. Virtually all DCS encoders send
100-200 mS of 34 hz as they unkey, and this mutes the receiver on the
other end.
--
Jim Barbour
WD8CHL
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