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
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