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Re: PCSAT2 telemetry

Hi Peter,

> Your PCSAT2 telemetry page is excellent, but can you help me to  
> understand a couple of things please.

Thanks, much appreciated. Here we go....

> How can I tell the time for which the telemetry data is valid.

It contain the very latest telemetry received, even if it appears to  
be old. We currently have only about 12
stations around the world feeding it. So there's a delay between the  
UK & VK and ZL and USA.
The USA to UK delay is only 15 minutes but that depends on the  
visibilty throughout the day.

The data is fed from the ground stations into the worldwide APRS  
network and only takes a
few seconds to get to my server.

> The time at the top of the page seems to be the time that the page  
> was accessed,

It's just in case someone does a screen capture of the telemetry so  
that they know the context. The Lat/Long is the
sub-sat point of the ISS at that time.

> and the telemetry may be quite a bit older, presumably if no-one  
> has copied it for a while. The 'frame time' fields seem to be all  
> different and I can't figure out which (if any) are the times for  
> the reported telemetry frame.

The frame time is the time at which it was received by my server  
rather than at the station.

To complete the telemetry display takes four packets of data hence,  
00, 01, 10, 11 against the Frame Time
and data element. The colour (in shades of blue) indicates the  
latency, the brighter the colour, the younger
the data, saves doing the cross reference back to the frame time when  
you're reading the data.

> I am particularly keen to know when the PSK31 transponder is on.  
> Your web page has a reference to 'PSK Bit' and 'PSK Bkup' and 'PSK  
> OFF'. How should I know from these whether the PSK31 transponder is  
> on or off?

Currently the 'B" side of the device is in use. (a longer explanation  
can be found about this on Bob's site)
so only look at the right hand column. The PSK31 will be on then the  
PSK Off is coloured GREY and off when
coloured RED, the condition at the moment during testing. We had a  
situation where Bob turned it on this
afternoon over Maryland and it didn't get turned off until it got to VK.

PSK Bkup is where the primary operation is on the B side but we are  
also using the TXA for PSK.
RED = on, GREY = off.

> Finally, there are references to TXA and TXB. Which is which, in  
> terms of the frequency. Is TXA on 435.275 MHz and TXB on 437.975MHz?

Yep, that's correct, both were running this afternoon for a short while

> 73
> Peter G3PLX

Hope that helps


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