Scott, your math is off by +10dB.
On 4/21/06, Scott Zimmerman <[EMAIL PROTECTED]> wrote:
> Guys,
>
> I think you're missing one detail here. 146.73 minus 146.85 is 1200 KHz.
> Twice the
> typical 2 meter split of 600Khz.
>
> I'm not sure EXACTLY why it's happening, but the math here has BAD written
> all over it. Anytime you deal with multiples of your input to output
> frequency separation, it's not a good thing.
>
> I wonder if the two repeaters are using the same PL tone? If so, does one,
> or both encode that tone as well?
> This could help explain putting the repeater in PL not helping to eliminate
> the interference.
>
> I think Ken is on the right track with an audio delay causing a howl. It's
> not a necessity however because of the RF delay in the possible feedback
> path. Realize that even at the speed of light (in free space) RF
> transmission and reception are not instantaneous.
>
> I think your best bet is to find a different frequency or location for one
> of the repeaters if possible.
>
> Scott
>
> Scott Zimmerman
> Amateur Radio Call N3XCC
> 612 Barnett Rd
> Boswell, PA 15531
>
> ----- Original Message -----
> From: "Ken Arck" <[EMAIL PROTECTED]>
> To: <[email protected]>
> Sent: Friday, April 21, 2006 11:24 AM
> Subject: Re: [Repeater-Builder] That horrible noise
>
>
> > I'd be interested in hearing the wav file you recorded, Dave
> >
> > But bear in mind that your comment that it's not coming from either
> > repeater could easily be wrong. As a matter of fact, if you're running a
> > delay in the audio path of either repeater, one of them is most definately
> > involved. It sounds like a typical spur/mix/intermod issue to me, probably
> > involving a 3rd party.
> >
> > Anyway, let's have a listen.
> >
> > Ken
> >
> > At 02:55 PM 4/21/2006 -0000, you wrote:
> >>
> >>
> >>Two VHF repeaters in town have been bothered by this from time to
> >>time.. The first, which only occasionally gets it, but gets it LOUD
> >>when it happens, is 146.730- The second (mine) at 146.850- is
> >>getting it almost continuously now, but weak, ranging from "will
> >>open squelch" (even with PL!) to "Will hold squelch but won't open
> >>it" Unfortunately, it's putting enough energy out at low
> >>frequencies that the PL board is seeing a tone, so PL won't save me.
> >>
> >>
> >>The noise has an echoing quality that I think is VERY distinctive,
> >>but I can't figure where it's coming from.
> >>
> >>It's not happening in either repeater, we've had the opportunity to
> >>completely shut down the machines when it's happening.
> >>
> >>The two repeaters are maybe 1000' apart.
> >>
> >>I've only started having a problem with it since replacing my
> >>antenna so that I'm no longer stone deaf.
> >>
> >>I have a 5M wav file of the noise, if anyone's interested.
> >>It sounds like broadband noise at first, but then you notice
> >>the "feedback-ish" sound in it. At times we've heard what seems
> >>like bits of audio in the noise.
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>Yahoo! Groups Links
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> > ------------------------------------------------------------------------------
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> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
> >
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