Jeff,
Good explanation, especially the fluttery/noisy user signal.
Would this general theory apply for factory Micor DPL boards as well?
I might run my repeater using DPL since that is what I have available
and its working fine.
Tony
On 05/03/2010 02:36 PM, Jeff DePolo wrote:
I don't have a schematic in front of me, but if your plan is to key
voltage
to the board on/off, this won't work ideally because the vibrasender reed
takes a little time to "come up to speed".
Since the repeater transmitter is still keyed long after a user
unkeys, just
muting the encoder seems like it would work fine all by itself.
Whether the
radio does or does not understand reverse-burst shouldn't matter. RB would
mute the receiver quicker on radios that do understand RB, but unless your
courtesy tone, ID's, etc. start to be played out very quickly (like
within a
few hundred ms) of a user unkeying, even radios looking for RB should mute
before those ID's and CT's air.
Also consider what happens if a user is noisy/ratty/fluttery into the
repeater. As the COR briefly goes inactive during a fade, you're going be
switching PL phases. This will tend to make the user sound even more
choppy
on listener's radios that are using PL decode. You'd be better off not
having the phase change, and just having the PL drop out briefly
without RB,
and then recovering in-phase when COR goes active again - less chance of
having the user radio mute intermittantly.
--- Jeff WN3A
> -----Original Message-----
> From: Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder%40yahoogroups.com>
> [mailto:Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder%40yahoogroups.com>] On Behalf Of N1BUG
> Sent: Monday, May 03, 2010 3:18 PM
> To: Repeater-Builder@yahoogroups.com
<mailto:Repeater-Builder%40yahoogroups.com>
> Subject: [Repeater-Builder] IDEA? Re: Micor PL encoder
> modification (TLN5731A)
>
>
>
> My original plan was to let the transmitter PTT control the Micor
> encoder board as usual, but supply a "valid user signal present"
> logic input to abruptly stop the tone when there is no user signal
> present... thus allowing the controller to keep the transmitter
> keyed for IDs without PL tone. This would also kill the reverse
> burst capability.
>
> But wait! (this is a little complicated to explain)
>
> What if I divorced J401-2 from keyed filtered A+ on the exciter and
> instead used my "valid user signal present" logic to supply keyed
> filtered A+ to that pin? The controller PTT would control
> transmitter PTT as normal. "Valid user signal" logic would control
> the tone encoder.
>
> Suppose I then put a diode between the collector of Q707 and J401-4
> (delayed keyed filtered A+) and used logic from the collector of
> Q707 (inverted) to pull Pin 701 low when Q707 shuts off.
>
> I think this would:
>
> 1) allow the controller to keep the transmitter keyed for *both*
> valid user signals and IDs by way of normal transmitter PTT
>
> 2) allow valid user signal logic to control the tone encoder in such
> a way that there would be no tone output unless there was a valid
> user signal... and allow the decoder to do reverse burst after loss
> of valid user signal, then abruptly kill the tone instead of
> reverting to "normal" tone.
>
> If anyone followed my poor description... are there flaws in my
> thinking? Perhaps I am over-engineering here?
>
> Paul
>
>
>
>
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