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Old July 27th 03, 01:29 PM
Richard Hosking
 
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I have a HP 141 series device which is reasonable from the point of view of
strong signal handling.
It is surprisingly easy to produce intermodulation effects at levels lower
than you would expect.
A "forest" of signals at -20 dBm will produce IM effects by the additive
effect of all their amplitudes.(you could easily get this from a 40M dipole
at night for example)
In fact, my friend Rod Green has done an article for QEX on a "figure of
merit" device to test receiver strong signal handling which consists of a
"comb generator" with harmonics every 20 KHz, and a bandpass filter covering
the band of interest - say 7.0 to 7.2 MHz. At a comb level of -20dBm most
receivers will be overwhelmed.

Richard

If I were designing a spectrum analyzer for the electronic instrument
market, I would shoot for at least meeting Hewlett-Packard Agilent
or Rhode&Schwarz specifications...R&D budget willing. That's a bit
steep for the hobbyist area.

The problem is that real incoming signals and the analyser's spurious
responses all look very much the same on the screen. When you can't
trust what the analyser says, it becomes very hard to understand what's
really going on.


Sigh. A spectrum analyzer, almost ALL of them, is one of the easier
instruments to characterize from the outside, using other instruments.
Frequency span, logarithmic linearity, passband of the final IF are all
relatively easy to determine from the outside.


Len Anderson
retired (from regular hours) electronic engineer person



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Old July 28th 03, 08:04 PM
 
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Mmm. Postscript documents. Real useful. NOT...


I know the feeling.

However, Paint Shop Pro 7 will read PS files these days.

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Old July 28th 03, 08:04 PM
 
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Mmm. Postscript documents. Real useful. NOT...


I know the feeling.

However, Paint Shop Pro 7 will read PS files these days.

  #48   Report Post  
Old July 29th 03, 02:10 PM
see sea oh ecks at you aitch see dot comm
 
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John Miles wrote:

Mmm. Postscript documents. Real useful. NOT...


Sounds like an interesting variation on the project, but without
documentation in a standard, open format, his audience is going to be
limited.


Postscript *IS* a standard, open format - perhaps moreso than most.
Try ghostscript as a freeware implementation for viewing and/or
printing the documents.

--
Chris Cox, N0UK/G4JEC NIC Handle: CC345
UnitedHealthGroup, Inc., MN10-W116, UNIX Services & Consulting
6300 Olson Memorial Highway, Golden Valley, MN 55427
email: (work) (home)
  #49   Report Post  
Old July 29th 03, 02:10 PM
see sea oh ecks at you aitch see dot comm
 
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John Miles wrote:

Mmm. Postscript documents. Real useful. NOT...


Sounds like an interesting variation on the project, but without
documentation in a standard, open format, his audience is going to be
limited.


Postscript *IS* a standard, open format - perhaps moreso than most.
Try ghostscript as a freeware implementation for viewing and/or
printing the documents.

--
Chris Cox, N0UK/G4JEC NIC Handle: CC345
UnitedHealthGroup, Inc., MN10-W116, UNIX Services & Consulting
6300 Olson Memorial Highway, Golden Valley, MN 55427
email: (work) (home)
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