[Premium-Rx] Our cherished receivers

[Larry Gadallah]

Hi all:

> From: "Michael O'Beirne" <michaelob666 at ntlworld.com>
>
> Hi chaps from a very wet London this evening.  Summer?
>
> I agree with Larry's comments yesterday.  The undeniable fact is that the
> figures for modern amateur gear are getting better by the month.  The recent
> detailed technical review of the K3 by Peter Hart in RadCom, July 2008, is
> an extreme case in point.  How many of our receivers can deliver a dynamic
> range of 101dB in a 500Hz bandwidth at just 2kHz off tune?  I suggest none
> and by a fair margin.

I can't recall where I saw the calculation, but what keeps playing
with (any) kind of radios fun is the fact that we are still not
anywhere the limits yet. The calculation I saw showed that the
theoretical dynamic range that is required is around 140 dB, so
there's still plenty of work to be done. The point that I was trying
to make yesterday is simply that a lot of military/government gear is
never subjected to the kind of (RF) abuse that amateur radio contest
equipment is, so it's not fair to simply write off amateur gear as
inferior. I'm just thankful that the boom in the cellphone industry
over the past 20 years has vastly improved the RF hardware available
while simultaneously reducing the costs of same dramatically.

I find it exciting to have a receiver where literally the only analog
component is a low-pass filter between the antenna jack and the ADC:
It's a whole new world compared to what I'm used to.

>
> But (and this is the killer but) is such gear getting any more fun to use?
> I suggest not.  As I mentioned in my last post, a K3 in a 19 inch box built
> to WJ or Racal quality would be wonderful - but dream on.  Perhaps a K4?
>
> There is an obvious analogy with cars.  Would you rather own a pristine
> Silver Cloud or a modern BMW?  The former are not too expensive to buy but
> cost a fortune to run, and what a car.  The latter car is expensive but
> reasonable to run and has all the gizmos.  However you can always fit a
> satnav into an old Rolls with skill.

Being a bit of a computer nut too, the analogy that comes to my mind
is that you can buy a very powerful, fast and cheap PC nearly
anywhere, but it won't have the same "feel" as a Sun, DEC, or HP box
from 20 years ago ;-).

>
> And this makes me wonder whether we can improve the sparkle of our older
> gear with useful gizmos hanging on the IF outputs - such as improved
> detectors and waterfall displays.  Already a Racal bargraph from the 1980s
> with tuning increments of 10Hz will transform the tuning of any receiver.
>
> Any ideas guys?
>
> 73s
> Michael
> G8MOB

Cheers,
-- 
Larry Gadallah, VE6VQ/W7 lgadallah AT gmail DOT com
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