Kris Kirby wrote:
> On Tue, 26 Dec 2006, Jim B. wrote:
>> Actually, that sounds like standard 2-channel, 4-wire tone remote
>> operation to me, where it's required to listen to both channels all
>> the time. Is there 2 rx's in this box or just one? If just one, it
>> likely has some sort of scanner in it. An option on those was called
>> PSLM, or priority search lock monitor. It was just a simple 2-channel
>> scanner circuit that toggled between the two rx channel elements. I
>> think there may have even been a 4-channel version.
>
> I just got the remote, I don't have any details about how the actual
> transmitter and recievers were rigged other than what was written on the
> inside housing of the remote.
Gotcha-really hard to know the whole picture with only a piece of the
puzzle ;CD
>> Also CTCSS should not have any effect on any of that, other then they
>> probably have a CG disable circuit, which in commercial service it is
>> required to listen carrier squelch briefly before tx'ing. It likely
>> will toggle rx into CSQ, then back to normal after tx is keyed.
>
> For some reason, the remote adaptor (radio side) seems unwilling to
> switch to transmit when the monitor is active,
Can't say I understand that, it is definitely not normal. Usually a PTT
is used to reset monitor to normal...
> and I've noticed that
> when I change from F1 to F2, the remote doesn't follow until the
> transmit button is pushed.
That is normal. Tone remote units normally don't send freq select tones
until PTT is pressed. Some newer consoles do seem to be set to send
those tones when the button on the console is pushed, but this seems to
be reserved for large dispatch console-type systems, like a newer
Centracom, Maestro, as opposed to a single desktop-type unit, like the
little CPI's or, say, a DGT-9600 or an RCN1000.
I've also noticed that the remote flips the
> transmit when the handset is removed from the cradle, presumably to make
> sure the radio is on the selected TX channel.
Yeah, that was probably intentional to try to do what I was describing
above. Probably just a jumper somewhere. Sorry, I don't have info on
that vintage on controller :c{
> I'm learning about this thing as I go,
Sometimes that's the best way!
> and I can see the tones on the
> O-scope, so I know *something* is being generated, but I wasn't able to
> locate my buttset so I could actually listen. I suspect either my tones
> are too low or too loud for detection. I'm at a bit of a loss as to how
> exactly "standard" four-wire, two channel is supposed to work -- I see
> most tones on pair one, but some tones I see on pair two, which throws
> me off a bit.
That is odd. Usually everything is sent on the tx pair, and only rx
audio comes back up the other pair...
>
> Not being able to reliably use monitor or PTT is a bit off-putting as
> well, but I suppose when I get the tone levels right things should start
> behaving.
You will be looking for high-level guard tone (2175hz) at about 0 to +10
dBm (don't forget to terminate the line with 600 ohms if it isn't
connected to the panel!), followed by a function tone slightly below
that (not sure, maybe 3-5 dB below HLGT?), and low-level guard tone
(LLGT, also 2175hz) at 30 db below HLGT to maintain tx. The loss of that
LLGT is what unkeys the transmitter. (Maybe you already know that, but
it doesn't hurt to mention it for others who may not!)
--
Jim Barbour
WD8CHL
