[Premium-Rx] Fw: Help choosing HF receiver

Mon Jul 3 04:25:22 EDT 2023

The perceived receiver performance is influenced primarily by factors that the user
has very little influence over; the noise/RF environment and the adjacent channel properties of other transmitters.

It is very seldom that receiver characteristics or performance themselves will have a governing influence.

I speak from some 40 years professional experience of specifying, assenbling and operating large HF systems for both civilian and
defence purposes, using equipment ranging from "cheap" to "extremely expensive".

SDR:s today have an edge in almost all aspects, and their only shortcoming is when extremely strong (>120 dB over the noise floor)
unwanted signals are encountered, such as when operating with co-located transmitters. 

The Winradio Excalibur surpasses almost all analogue receivers, but receivers such as the E1800 have a slight advantage when
such signals are encountered, as they "degrade gracefully" when the adjacent channel signals increase.

One recent system was assembled using second-hand SRT CR91 receivers which replaced ageing (45-50 years of H24 operation) 
SRT CR300 receivers. The main difference became that the control system was simplified and the spare parts situation became more manageable. Performance-wise there were very small, if any, differences,  

The reader should be quite suspicious about claims of "wonder receivers", as the main characteristics of a MF/HF receiving system
are determined outside the receiver itself by the RF environment. Abilities to handle strong adjacent channel or out-of-band signals
will have the most influence performance-wise, with IF and audio passband shape next. 
When listening to weak AM signals, it pays to use demodulation methods
that make the most out of the received signal energy, such as synchronous demodulation and "exalted carrier reception". 

73/Karl-Arne
SM0AOM

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Datum : 2023-07-02 - 23:17 ()
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Ämne : [Premium-Rx] Fw:  Help choosing HF receiver

Hello Joe,

 Yes, an EK895 owner told me that the perfomance was very similar,almost equal, to the Airspy HF+ discovery not discerneable difference.

 I have already got a SDR receiver, a Winradio G33DDC Excalibur Pro, I am not very happy with it. Every now and then overloads, it has fitted a preselector and attenuator but I am not totally convinced about the perfomance. 
For my taste is too noisy, comparing weak signals my Lowe HF-150 is equal if not better in most cases. As antenna I use a Wellbrook ALA 100M.
Maybe I should add add an external USB card in order to improve the Winradio.

Regards.

    ----- Mensaje reenviado ----- De: Joe Jesson <jejesson4 at gmail.com>Para: Enrique Fernandez García <enriqueeeeee2001 at yahoo.es>CC: Premium Premium receiver <premium-rx at mailman.qth.net>Enviado: domingo, 2 de julio de 2023, 22:36:29 CESTAsunto: Re: [Premium-Rx] Help choosing HF receiver
 I also like AM DXing and my favorite classic is the Scott Philharmonic crome-plated radio.  The Wj-8718 had terrible audio until I realized I had to match the radio's audio output of 600 ohm to a 3.2 ohm speaker. All was good after that.
If you want to try BCB dxing on the latest SDR receiver (Airspy HF + Discovery) with an active regenerative loop, I think you will be surprised! Adding a klipsch speaker was like icing on the cake :-)

On Sat, Jul 1, 2023, 4:34 PM Enrique Fernandez García via Premium-Rx <premium-rx at mailman.qth.net> wrote:

Dear group,

After having some conventional receivers, Drakes, Lowe, AOR and a Winradio SDR I have decided to make a step further and geting a professional receiver, although I had already got a Racal 1772 and for my taste it was quite noisy.

I would be very pleased if the members of this forum could indicate me in the right direction and throw some light in which receiver to choose since I am a bit confused in this aspect.

I am mainly interested in voice signals, not digital modes, mainly BCB and SWL, digging tropical band stations out of the mud so audio recovery and audio in general is quite important.

After surfing the web and readind on eham and in forums, I have in mind these receivers (in no special order):

 -Racal 3791, but it is said that the audio is not as pleasant as the RA 3701.
 -Racal 3701, on the contrary of the DSP version RA3791 is an analogic IF design  and as indicated before its sound is ways better but it does not have the additional independent IF BW options
- R&S EK895, with the quasi-continuous tuning fitted.
- WJ 8711A
- Cubic CDR-3280

 Any help and thoughts are very wellcomed. Any other receiver apart from the above?

 Thanks in advance
 Regards
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