[amsat-bb] Returning to satellites and forgot lots

[Mike Seguin]

Hi Gary,

Long time!

Why not use the FT-736R to send power up the coax to your preamps if 
they can use that. In the FT-736R, there are jumpers to enable 12v on RX 
up the coax. You turn on the preamps by pushing the preamp switch in the 
upper left corner.

There are some pros/cons of doing this based on TX power used/amps etc. 
Sequencing might be better...

I built a small sequencer in to my FT-736R that holds off RF for ~ 100 
ms on TX. With that, I can use amps and not worry about 'hot switching' 
relays.

Also, if you're using an amp, some of them don't pass DC. (like my 70 cm 
Teletec). In that situation, you can externally power the preamp, but 
then you have to figure out switching (probably sequencing).

In my case, I wired the "preamp out" voltages to some RCA connectors I 
mounted on the back of the FT-736R. I send this up the tower through my 
control cable.

For CAT, I use SatPC32. As you know, the FT-736R is kind of brain dead 
in that it can only accept a few input commands. It will not send things 
like current freq etc back to SatPC32, so you must tune the rig within 
SatPC32. Not an issue on the FM birds. A bit of a pain on the linear birds.

I built my own CAT interface. Basically an RS-232 to TTL converter. Lots 
of info on the Web.

I still have a copy of your "Working the Easy Sats".

Mike

On 10/24/2019 1:56 PM, Gary Rogers via AMSAT-BB wrote:
> I'm returning to satellite operations after being off the air (entire 
> station disconnected) for over two decades and am looking to put my 
> FT-736R back to use in the manner for which it was intended.?? However, 
> while I'm OK with my 2M setup (rig to amp/pre-amp unit to Eggbeater) I'm 
> less confident on 70cM, specifically how not to toast the mast mounted 
> pre-amp. I know that I need to inject the voltage for the pre-amp using 
> the little control box that came with the pre-amp (Mirage KP-2 series) 
> but how do I ensure that the voltage drops when I transmit so the 
> pre-amp is taken out-of-line??? Perhaps there is a FAQ or diagram for 
> this out there somewhere?
> 
> Also, what is being used for CAT control these days if I'm using SatPC32 
> for tracking?
> 
> I feel like such a newb!
> 
> Thanks!?? -de Gary WA4YMZ
> 
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-- 

73,
Mike, N1JEZ
"A closed mouth gathers no feet"