[hpsdr] [Hpsdr] Call for Comments - ALEX

[Graham Haddock]

Henry Vredegoor wrote:
> (Duplex operation)
>
> Remember we are dealing here with the most sensitive part of the receiver!
>
>   
All:
What kinds of duplex operation are you contemplating?

1.) Simultaneous transmit and receive through two different band 
transverters for satellite communications.

2.) Test equipment mode, ie, VNA or spectrum analyser with tracking 
oscillator.

3.) Any others???

Question:  In duplex satellite type of operation, can we assume that the
MERCURY and PENELOPE are always on different frequencies? If so, what
is typical, and specifically, what is the T-R spacing from the viewpoint 
of the
Mercury and Penelope (not what the antennas see) ?

Depending on the amount of isolation required, duplex operation might 
require
a second transmit filter board in a separate housing.  For test 
equipment, I assume
the isolation required is the dynamic range of the test equipment plus 
10 dB or so.

For duplex transceive, it is highly variable according to the frequency 
difference.

[Phil H:  What is the card to card isolation for a MERCURY and PENELOPE 
plugged
next to each other in a common ATLAS bus?  Not even a PC card between them
there.  ;-)  ]

--- Graham / KE9H

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