[amsat-bb] Re: beginner question re: uplink power
mat_62 at netcommander.com
Sun Oct 19 15:18:01 PDT 2008
If i remember correctly there was gent on this board awhile back that
reported some issues with the RF switching of Ramsey preamps. I believe the
problem had something to do with the switching cutting in and out while
using SSB. I can't remember the exact issue. though. Still you may want to
take this into consideration when making the decision whether to go with
hard switching or not.
----- Original Message -----
From: "corner5" <corner5 at comcast.net>
To: <amsat-bb at amsat.org>; <corner5 at comcast.net>
Sent: Sunday, October 19, 2008 4:22 PM
Subject: [amsat-bb] Re: beginner question re: uplink power
> Thanks for replys (Re: beginner question re: uplink power)
> In response to two points contained in replys from helpful others...
>> Ed - KL7UW: I wonder if the Ramsey preamps allow for "hard" switching.
>> That is
> by separate control line that the radio PTT controls. Then You have
> no issue with RF power and would run the units with the RF sense
> disabled. I should state that "many" (dare I say most) experienced
> VHFers that run high power (>100w) use hard-wired switching. I know
> of NO eme stations that use RF sense control lines.
> A: Ed, yes this is a good suggestion. In fact these preamps are very
> simple units. No, they do not have any switching that would
> allow for external PPT communication from the TS2000 (0-100w at 2m,
> 0-50w at 70cm). That said, I certainly could add my own mast mount external
> to do the switching. I also could simply install a DPDT or TPDT switch at
> the shack end and manually do the switching. This last
> approach could lead to smoking the preamp the one time I forget to toggle
> it out of line. So, in the end I chose to
> go with the RF sense remote switch. I hope the need to contain my uplink
> RF withing a chosen range (0-10 or
> 10-30 or 30-100 watts) will not be too limiting.
>> Roger,WA1KAT: Hard wiring, as has been suggested, is your safest choice.
>> As the switch has
> the relay in it, maybe Ramsey can tell you where to tap in to directly
> switch the sensor.
> A: This is a very interesting approach. If I understand your idea here,
> you suggest to use the relay that is
> on the RF switch board and toggle this relay with a PPT signal from the
> TS2000 (and not make use of the RF sense at all. Yes?
> I do not know about the details of using the PPT signal in this way. I
> guess I need to hope that the PPT signal
> is compatible with the relay (voltage). And then if I need to abandon the
> RF switch all together, are there suggestions
> as to what is a good (not too expensive) remote relay design?
> thanks all!
> .paul AC0z
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