[Premium-Rx] DXing in MW nearfield

[Carcia, Frank A. HS]

I agree, I measure a number of different spaced signals starting at 
1 KHz. Then I work my way out to 50 KHz
spacing to understand the effect of the 
filters in the first IF compared to the first mixer.   fc

-----Original Message-----
From: John Perlick [mailto:p at mn.rr.com]
Sent: Friday, May 30, 2003 8:57 AM
To: Carcia, Frank A. HS; 'michael j brown'; premium-rx at ml.skirrow.org
Subject: Re: [Premium-Rx] DXing in MW nearfield


And 100 KHz is a really unrealistic, useless spec.  Should be 5 to 10 KHz.
That's about the MAX we run across in SWL or ham service...
----- Original Message -----
From: "Carcia, Frank A. HS" <francis.carcia at hs.utc.com>
To: "'michael j brown'" <piggin at mindspring.com>; <premium-rx at ml.skirrow.org>
Sent: Friday, May 30, 2003 6:56 AM
Subject: RE: [Premium-Rx] DXing in MW nearfield


> That is why most receiver specs measure
> dynamic range with 2 signals spaced 100 KHz. to take advantage of the
filter
> in the first IF.     fc
>
> -----Original Message-----
> From: michael j brown [mailto:piggin at mindspring.com]
> Sent: Thursday, May 29, 2003 11:32 PM
> To: premium-rx at ml.skirrow.org
> Subject: [Premium-Rx] DXing in MW nearfield
>
>
> My situation is similar to johns.One mile from a 5kw on 570, and three
> others in that class within a couple of miles.In the specs for the 3031A
> they specify the strength of the wanted signal@ 31.6microvolts and then
use
> two signals at +30 and +60 kc at a strength of 100millivolts(in the 100 to
> 525kc band) This should still keep products below the wanted signals
level.
> Mackay also says A 1 millivolt signal will change less than 3db with a
> 100millivolt signal 10kc away.These are the only specs I have ever seen
> written in this manner.Note it does not address volts of RF.Blocking
> performance is ok in my real world signal hell.But the preselector really
> helps.Most radios without massive LO injection and giant dynamic range, in
> combination with some preselection can't hack it.The 3031A does not
feature
> massive dynamic range.Or watts of LO injection.But the preselector works.I
> imagine many premium RXs would fare poorly within the distance John is
> coping with.But I doubt many write specs that would really tell you what
> happens with 2 volts of rf 10kc away will cause your radio to do.....
>
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