[SixClub] 6 meter repeater PL tones

[Chris Boone]

BUT using PL doesn’t make the PROBLEM or MIX go away...it covers it up but the rptr range is actually less now...

My personal experience on UHF......440 GE rptr on 23 story building...NO desense, etc with the rptr and duplexer into dummy load...had been on 444.1 but swapped with another rptr that had some problems...so I ended up on 444.8......and SOMEWHERE in the building was a scanner or monitor rcvr listening to the local Sheriff rptr on 460.500---wanna guess what the IF offset was?? 10.7MHz....low side injection (can you see where this is going?) and tada...constant low level signal on 449.80!!! So we added PL but the decoder would not unmute because of the heterodyne between the user on the input and the scanner LO...
We went carrier SQ and had better range though you still heard the "tone"....finally ended up moving to 444.5 where it is still today

If you cannot run the rptr in carrier mode, don’t expect better in PL mode!!! The problem is just hiding!

Chris
WB5ITT
And I run flat audio on all my systems..

> -----Original Message-----
> From: sixclub-bounces at mailman.qth.net [mailto:sixclub-
> bounces at mailman.qth.net] On Behalf Of donroden at hiwaay.net
> Sent: Wednesday, April 21, 2010 4:25 PM
> To: World Wide Six Meter Club
> Subject: Re: [SixClub] 6 meter repeater PL tones
> 
> "Back in the day" ( pre-expensive cavety filters ) a repeater owner
> could PL the input and not the output.  That way, if there was any
> desense or mixing products, the repeater would not "hang-up", becaued
> the interference  DIDN'T have the correct PL to trip the COR.
> Running the same tone on the transmitter would be counterproductive to
> eliminating the "hang-up".  Repeaters that passed ALL the audio
> suffered from the same problem.... the PL passed on through.
> 
> most used a high-pass audio filter ( above the PL frequencies ) to
> eliminate the pass-through.
> 
> Don WA4NPL
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