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Re: beginner question re: uplink power



Paul,
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.
73,
Michael,W4HIJ
----- Original Message ----- 
From: "corner5" <corner5@comcast.net>
To: <amsat-bb@amsat.org>; <corner5@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@2m, 
> 0-50w@70cm). That said, I certainly could add my own mast mount external 
> relay
> 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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