[Repeater-Builder] Micor receiver voting tone

Fri, 18 Mar 2005 10:22:54 -0800

There was both a factory option and a field modification kit that allowed conventional Motorola Micor stations to be used in SpectraTac systems.

First, a SpectraTac encoder card was added in the repeater card cage to generate the status tone that allowed the "in-cabinet" (repeater) receiver to vote along with the remote receivers.  The encoder card normally produces a steady tone that is interrupted when a signal is received.  The encoder module has low and high tone slide switches which are used in equalizing the tone levels (which are adjustable on the encoder card).  Secondly, the status tone is routed out through a special four wire line driver so that the repeater receiver status tone and any received audio is routed on one pair to a SpectraTac comparator.  The second pair of audio lines on the line driver is used to bring the "voted" audio from the comparator back to the repeater for retransmission. 

There is also provision for "in-cabinet" repeat, which means that if the comparator dies the repeater will repeat whatever audio the repeater receiver is receiving just as if there was no SpectraTac system connected to it.  The special "SpectraTac Line Driver" also had circuits to add gain at certain audio frequencies so that the repeater's receiver audio response more closely matched the response curve of the remote receivers.

Marv Hoffman, WA4NC
Boone, NC

skipp025 wrote:
If you need a Spectra Tac type operation, there are 
modules (for the card-cage/backplane), which serve 
up the proper tone encoding functions. Most often 
you will see a special version of the line driver 
module and a "spectra tac encoder" module. 

Motorola also had an earlier A-B tone voting system 
(that seemed to work pretty well). Finding cards for 
that system would be hit and miss at best. 

Depends on the voter you have, but the spectra tac 
module manaul should have descriptions of the more 
common back plane modules. The common module manuals 
can often skip over the spectra tac options as they 
are/were special order or "as-built". 

I can't see why any duplex chassis couldn't be made 
to generate a proper encoder tone sequence, else you 
just need to properly add the circuit. 

Cetec Vega had a popular external voter tone encoder 
module, often seen installed after-market. 

cheers, 
skipp 



  
"bd6xray" <[EMAIL PROTECTED]> wrote:
Does a Micor base receiver, unified chassis, have any capability
    
for 
  
generating a voting tone?  The "Control and Applications" manual
    
does 
  
not make any mention of any cards that would do this.

Al Hajny
    







 
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