Hi Bob,
In the stock configuration, there is no
local speaker. What you would call the
speaker audio amplifier output is dumped
into an 18 ohm resistor (of proper wattage).
The above practice is common with many kit
and non commercial receiver boards used in
repeater service. Again, this is one area
where Spectrum does something very well,
supplying the repeater audio from buffered
gated op amps not related to the speaker amp.
Hamtronics and Maggoire also offer discriminator
audio with Hamtronics gating the main speaker
audio off before the audio amp circuit (making
the high side of the volume pot a useable audio
"tap" location. Maggiore actually gates the
LM-380 ic directly, meaning the volume pot high
side is not gated.
I used the Maggoire terminated audio tap in the
just completed 220 project after measuring the
distortion and bandwidth with a suspect eye
(and test equipment). I was pleasantly surprised
how well the circuit functions with minimal
disortion at minimal to mid range volume settings.
Another surprise is how well the discriminator
circuit of the Maggoire Receiver preforms
(better than some "high-end receivers").
If you wanted a local speaker (which is
actually undesired in most cases), you'd
have figure out something out, which would
work for your specific requirements.
Maggoire places the volume and squelch pots
down on the pc board, which I feel is one
of the better locations anyway. Pots in view
and access of the general public, get turned
("in the middle of the night") unless you lock
them down hard with a nut-fixed control pot.
If you obtain your repeater audio from
the available discriminator source, you
could easily use the speaker amp section
for it's "normal application" ie... local
speaker audio.
Terminated speaker audio is not a big deal, I
did it for some years when the main repeater
box was a Micor Mobile. At the time, it was
very easy to do and the sub tone filter really
helps. I trail the current Maggoiree circuit
with a sub-tone (PL or ctcss) filter before the
controller input. Works great, less filling...
cheers,
skipp
> Bob Dengler <[EMAIL PROTECTED]> wrote:
> At 3/23/2005 05:55 PM, you wrote:
>
>
> >Re: Maggiore 220 Receivers
> >
> >I'll second (or third that)... I just put
> >another on the air. The only thing I don't
> >like about most of these type receivers is
> >how they offer up the local speaker audio
> >as the input to the repeater controller.
>
> So what happens if you adjust the local
> speaker volume? Does it mess up
> the repeat audio level?
>
> Bob NO6B
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