Re: [Discuss-gnuradio] AR5000 and downconversion

[Dave Emery]

On Wed, May 14, 2003 at 09:36:36PM -0400, John R. Ackermann   N8UR wrote:
> Hi Alan --
> 
> I doubt you'll find many radios that support a 6-7MHz bandwidth around a 
> 10.7MHz IF.  That's way too great a percentage of the center frequency for 
> traditional radio design to work with.  I suspect the 10.7 IF in the AR5000 
> is not going to be able to handle more than NBFM, or at most WBFM (eg, 
> 200kHz or so) bandwidth without major surgery that would likely render the 
> radio useless for normal tasks.  A radio that supports TV bandwidths is 
> likely to have a much higher IF, anywhere from 45 to 70MHz or higher.
> 
> John


        Not true.  The ICOM R-7000 and R-7100 and I believe the R-8500
all were designed to be optionally used with an external NTSC video
demodulator boz that hooks up to the 10.7 mhz output.   This implies
a 6 mhz bandwidth at the 10.7 mhz output and this matches my sxperiance
with these radios.

        I don't happen to currently own a AOR-5000 family radio,
but I am pretty sure its 10.7 mhz IF output is comparable.

        All of these outputs  are before much of the IF gain, most of the
AGC action and were designed for use with wideband demods such as NTSC
video demods and also with spectrum display scopes (panadapters).


-- 
        Dave Emery N1PRE,  address@hidden  DIE Consulting, Weston, Mass 02493
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