--- Jim Reid <jimr.reid@verizon.net> wrote:
>
> Yes, appears to use relays for selecting the
> preselector band
> pass filters. The RX-340 uses diode switches;
> relays are
> better for linearity's sake. Relays "can"
> contribute to a higher
> intercept point if the diodes they replace are not
> really
> linear over a wide dynamic operating range. Relay
> contacts
> are linear, hi!
Actually what I perceive to be the RX (and low level
TX?) band pass filter board (upper right radio
quadrant of "voldermort-orion-inside3.jpg") looks like
it may be diode switched unless there are small relays
underneath the board. The only relay switched filters
I see are the TX low pass filters.
>
> Also note, perhaps two missing PC boards. One where
> that
> card is sitting, lower left slot in the top right
> hand picture.
> Maybe something missing in the space to the left of
> that one;
> interesting. At first I thought the card was
> "hiding" something,
> but then saw the standoff's which would hold the
> missing board.
I would bet it is where the optional antenna tuner
lives.
The one design feature I found interesting is the
"back bone" board that runs down the middle of the
radio from front to back (sandwiched bewteen to
aluminum panels). It looks as though it terminates
into a connector immediately behind the front panel.
It also lines up with the vertical row of I/O
connectors in the middle of the Orion back panel. I
have to wonder if there are any active devices on that
board or if it is strictly a passive back plane? It
also provides a tidy way to route the rear RS232 (and
perhaps some other) signals to the front of the radio
where the control function "brains" of the Orion
presumably are located.
I could not determine where the dual SHARC DSP's (and
associated ADC's) live, but I suspect they are on the
underside of the upper left quadrant of the
"voldermort-orion-inside3.jpg" picture.
Any one else have any wild speculations about the
design?
73,
Duane
N9DG
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