For some reason, I seem to have an excess of Line Driver cards :(
Neil
Mike WA6ILQ wrote:
>
> At 01:44 PM 11/21/04, Paul Kelley <[EMAIL PROTECTED]> wrote:
>
> >(big chunk chopped)
> >
> > > They seem to. In normal practice, the antenna relays are
> > > actually switched prior to the channel element being
> > > enabled. This function was incorporated into the Station
> > > Control Module by using the delays already built into
> > > that module. While I'm not suggesting the way I do it is
> > > the best, and while I don't make it a practice of hot
> > > switching the PA's, it does work and hasn't given any
> > > trouble, yet; however it's only been on the air a short
> > > time.
> >
> >Thanks for all the helpful information. I've given the
> >matter some thought to see if I could come up with some
> >sort of switching logic that would disable PTT, switch the
> >relays and then enable PTT.
>
> The flow chart and design of the common moonbounce
> preamp switching can be your starting point.
>
> >Ideally it would be nice if it did that when the PA is
> >switched in or out by a control function and when
> >AC power fails or comes back up.
>
> A line driver card could be stripped and a vectorboard
> mounted and used to hold a few "ice cube" relays to
> do the switching.
>
> Alternatively...
> I don't know about the other repeater controller manu-
> facturers but I could do it on an Scom 7K with a few
> macros triggered from digital inputs and controlling digital
> outputs.
> The AC Power present signal can be derived from the
> unregulated side of the power supply, or worst-case from
> a wall-wart 5v power pack... either way it can drive an opto-
> isolator which can be fed to a digital input on the controller.
>
> >Meanwhile I think I will just try some different relays
> >with the existing configuration and see if they hold up any
> >better than the DowKey type (unknown manufacturer) that I
> >used last time.
>
> I've found high power coax relays now and then at C & H Surplus
> a.k.a. C & H Sales in Pasadena, Calif. Phone is 626-796-2628.
> Don't know if they have a web site.
>
> Please post your results.
>
> Mike WA6ILQ
>
>
> Yahoo! Groups Links
>
>
>
>
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