[Discuss-gnuradio] Practicality of DC-light RF front-end?

[Marcus D. Leech]

I've been thinking about the practicality of a "DC-light" RF receiver
  front end, for radio astronomy in particular, but also for general use.

It seems to me that something like the MAX2116 (or similar direct-conversion
  satellite receiver) having a very wide tuning bandwidth (over 1Ghz), could
  be used as part of a very wideband receciver front end.

My idea would be to use the MAX2116 directly for signals between 950Mhz and
2150Hz, and
  to use a an UP-conversion stage for signals between about 5Mhz and 950Mhz. 
The idea would
  be to use another LO, at perhaps 945Mhz (just below the passband of the
MAX2116), and mix
  the incoming signals with that, filter, and feed to the MAX2116.  A small
collection of
  PIN diodes could be used to route the RF where it needs to go.

Building a 945Mhz fixed-frequency LO wouldn't be that hard, and mixers are cheap
and
  plentiful.

What do people think about something like that?

Other wideband receivers often use a collection of synthesizers and VCOs to
cover the
  wide bandwidth, but in this scheme, there's only 1 synthesizer to program, and
  a little RF switching.

-- 
Marcus Leech                Mail:   Dept W669, M/S: 04352P16
Advisor                     Phone: (ESN) 393-9145  +1 613 763 9145
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