[Premium-Rx] Rohde & schwarz ek895

Thu Jun 10 16:32:24 EDT 2021

In today's noise and interference environment, the performance of the receiver
has become quite unimportant, as long as the bandwidths and demodulation processes are
properly adapted to the signals that are intended to be received.
Practical comparisons between "expensive" and "inexpensive" receivers in simulated congested
spectrum segments occupied by real-world transmitters have shown quite small differences between
"Premium" and "Non-premium" receivers. 
The obsession shown about improving receiver performance by contemporary transceiver manufacturers has largely become nullified by the quite bad adjacent channel and sideband noise performance shown by the transmitters employed by the vast majority of HF users today.
Results of both theoretical and practical studies about attainable receiver performance in the congested environment
were summarised in the paper "Performance Limits for HF Communication Systems Using Realisable Hardware Solutions" which was presented at the Nordic HF Conference in 2019.
In this paper, very expensive receivers were compared to more mundane, using a synthesised RF environment with adjustable properties. The operational differences were in the order of single-digit dB.
So, dr. Rohde is quite right. No receiver is better than the transmitter signals it is trying to suppress...
73/
Karl-Arne
SM0AOM
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Från : premium-rx at mailman.qth.net
Datum : 2021-06-10 - 20:59 ()
Till : enriqueeeeee2001 at yahoo.es
Kopia : premium-rx at mailman.qth.net
Ämne : [Premium-Rx]  Rohde & schwarz ek895

  Hello Enrique,

  In regards to your question about the performance of an EK895 as opposed to other receivers...  

  Since you are asking this question in comparison to high performance receivers, I would say that there are two ways to determine this:

   1) Technical aspects: Laboratory performance test results such as IMD, Noise floor, Selectivity...etc

   2) Real life results: this is the most important for us. And it highly depends on a good antenna setup, properly located and even properly polarized.  Antenna setup makes a huge difference.  And even good audio setup, speakers and/or headphones.

  I compared an EK895 last summer in a side by side tests with AirSpy HF+ and HF Discovery SDR receivers. I was AMAZED at the overall performance of the Airspy with very low noise floor, great audio coming from my standard laptop, easy access to Modes/Frequencies/Filters/...... While EK895 performance was equal to my ears and not specially any better or worse. But then again this was mostly for weak signals and we all have different ears. 

   Dr. Ulrich Rohde once wrote someplace that the best receiver he ever had was EK895 MK2. I dont know of an MKII EK895, maybe updated software with higher serial number unit.  I am sure he has access to all kinds of Rohde updates.   I believe he uses R&S Active receive antennas which can be seen on his web site N1UL.  

  Dr. Rohde also once told me that a Receiver is as good as the transmitter's performance.

  One feature in the EK895 that did not seem to be working properly ( in my case ) was the 2 Notch Filters.  They seem to generate audio issues. No matter, EK895 is possibly one of the top 5 receivers ( Racal 3xxx, AEG1800/3, AOR7030+, .....).

  In my opinion EK896 is probably a bit better in features but never had one. 

   You may want to give Airspy a try as they are very low cost and worth every penny.  And concentrate on having good antennas ( active and passive ) that are properly isolated from feedlines with chokes, tuned/matched and even experiment rotating the antennas to change their polarization and observe how this improves reception.

   All the best.

   Ahmet Gundes

     Sent: Monday, June 07, 2021 at 7:26 PM

     From: "Enrique Fernandez García via Premium-Rx" <premium-rx at mailman.qth.net>

     To: premium-rx at mailman.qth.net

     Subject: Re: [Premium-Rx] Rohde & schwarz ek895

     Thanks you very much for your useful advices. I will go to the EK895 then, the 896 is more than I need and is out of my pocket.

 Regarding the WJ8711A, I already knew about the capacitor issue, apart from thatthere is a microprocessor noise when touching near tuning knob,this happens on SW frequencies. I have seen some of them on ebay,Israel, at a good price but heavily used. Finding one with the right sotfware version installed and in good working order is not easy.

 On page 4 there is a review/modification for the WJ8711 if you are interested:

     http://www.hard-core-dx.com/swb/1536.pdf

 Most important question for EK895 owners; any significant difference in catching/understand weak signals compared with other receivers?

 En domingo, 6 de junio de 2021 22:06:53 CEST, Raymond Boute <raymond.boute at pandora.be> escribió:

 Dear Enrique,

 Mased on my own experience, I would say that the ek895 has more

 features for use on the hf bands (including passband tuning and so

 on). but it also depends on installed options. The eb200 is smaller,

 goes to 3 GHz, and is more suited for measurement purposes.

 To facilitate comparison, I attach a quick user quide I made for both

 receivers a few years ago.

 73

 Raymond ON4DBV

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