[Premium-Rx] Question on older premium receivers compared to “modern” technology.

[sm0aom at telia.com]

A most interesting question.

As an HF systems designer and integrator, this subject has been quite 
extensively studied.

The last "top-of-the-line" analogue HF receivers, such as the Harris 
RF-590A, ITT-Standard Radio CR91, Collins HF-8054
or the pinnacle; Telefunken E1800A had distortion and blocking 
properties which were as good or even better than the SDR:s, when 
measured
at larger spacings.

These properties were considered decisive in the Cold War radio 
environment, where many high-powered propaganda
transmitters filled up the HF broadcast bands, and many high-powered 
commercial and military users also were
present. This made parameters as IP3, blocking and far-off oscillator 
sideband noise important.

SDR and DSP receivers have a quite different large-signal behaviour; the 
IP3 and blocking behaviours are about equal or slightly worse than
analogue receivers, but the oscillator sideband noise issue is 
essentially absent, but when the
dynamic range becomes exceeded the receiver overloads suddenly.
This makes close-in performance; both filter shape and close-in 
intermodulation much better for SDR:s than for analogue receivers,
but not "blocking".

However, the radio landscape has changed considerably since the 1980s; 
the number and emitted power of the broadcasters have diminished,
commercial and military HF is more transient and uses less power. The 
same can be said about amateur HF usage.
At the same time, the ambient noise levels have increased considerably, 
which in effect compresses the usable dynamic range.

There is experimental evidence that even "mediocre" receivers give fully 
satisfactory results in the current radio environment.
The performance differences between "top" and "middle-class" receives 
are hardly noticeable in a current congested spectrum,
as the adjacent channel and broad-band noise performance of transmitters 
will be determining.

Both theoretical and experimental studies in these matters have been 
summarised in two recent conference presentations;

Rolf Folkesson and Karl-Arne Markström
"Performance limitations in HF communication systems
composed of practical realisable hardware"
(Proceedings of the Nordic HF Conference HF19)

Karl-Arne Markström
"A generalised approach for performance evaluation of HF systems"
(Proceedings of the Nordic HF Conference HF22)

The "bottom lines" of both presentations were that money is better spent 
on
larger and better placed antennas together with transmitters having 
"cleaner" spectra.
The receiver performance as such is comparatively less.

Remember, "One $ in the antenna equals three or more $ in the radio".

73/
Karl-Arne
SM0AOM






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        Skickat: Friday, January 9 2026, 03:10
        Ämne: [Premium-Rx] Question on older premium receivers compared 
to “modern” technology.


  Help group:

  Has modern DSP receiver design in part 97 ( or even milspec usage) 
really surpassed the high performance  designs of systems deployed in 
the last 1980’s up to today.

  I was thinking of the Rockwell collins HF805() or the TCI receivers 
such as the 8174 or even Harris receivers compared to modern Kenwood or 
Icom receivers.

  It seems like the older units got very close to what is technically 
possible to what you can receive these days. With the QRM on HF, your 
only real advantage seems to really about more effective antenna systems 
for receiving.

  I really want to know. The challenge I have is if I should spend the 
effort to fix the older receivers I have or invest the money in more 
effective antenna systems.

  Thank you.

  Kevin







  BT







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