[ICOM] New IC-7700 announced at Dayton

[Jim M.]

The 7800 has an automatic front end preselector in the receiver.   If it is 
a good preselector, it will drastically attenuate signals outside of the 
frequency range you are tuned to... maaybe 50-100 khz I would guess.  This 
reduces strong signal intermod.  But that would make dual receivers 
difficult.  The earlier Icom rigs had front end tuned circuits, mostly for 
the transmit chain I would guess, but they also make it hard to dual receive 
on different bands - the front end tuners would kill receiver performance 
outside of the band of operation.  To perform well, a second receiver would 
need its own dedicated automatic preselector, and signal chain, which would 
drive the cost up.

Speaking of receiver preselectors, it's funny how things come back around - 
a decade ago all the "experts" thought wideband receivers were the way to 
go, no preselectors.  Fifty years ago the Collins people proved that a good 
front end preselector made for better receiver performance (i.e. the old 
R-390s).  Now they're back in the "modern" radios.  Just goes to show 
there's really nothing new under the sun.  Jim N4BE


----- Original Message ----- 
From: "Dick Flanagan" <dick at twohams.com>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Thursday, May 17, 2007 10:45 PM
Subject: RE: [ICOM] New IC-7700 announced at Dayton


> At 06:53 PM 5/17/2007, AD5VJ  Bob wrote:
> >Let's be sure we are being fair Dick. I don't think they said instead of
> >Dual Watch we are adding the capability to connect to
> >another RX.
>
> You are correct.  That was merely my observation.
>
> >Being able to watch two bands at the same time during a contest is a 
> >great
> >advantage. Works especially well at night for 80 and 40
> >to monitor both for activity at the same time.
>
> I believe that even with Dual Watch on the 756 P3 you can't listen to two 
> bands at the same time.  Different frequencies within the same band, yes, 
> but not on two different bands.  Perhaps Adam can expand on this.
>
> 73, Dick
> --
> Dick Flanagan K7VC NV SM
> k7vc at arrl.org
>
>
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