Lista QST de receptores.

[Rodrigo]

Boas,

Aqui vai a lista dos radios testados pela revista QST e ordenados pelo "2 kHz 3rd-order dynamic range"

http://www.remeeus.eu/hamradio/pa1hr/productreview.htm

Giro ver a posição das novas maquinas!!

Rodrigo

ct1bxt

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[Carlos Mourato]

Curiosamente os SDRs  "anões" não constam da lista! Apenas o FLEX aparece em algumas linhas, mas nem é assim como se diz a "fina flor". Ao que parece a "belissima" recepção dos SDRs advem de filtragesn DSP já na parte de audio!. Se calhar um SDR a sério, com performances de primeiro plano custa uma pipa de massa, mas daquelas pipas gordas! O Kenwood TS590 é que continua a dar cartas!...Deve ser dos muito poucos equipamentos da Kenwood, da era moderna que me seduz!

73 CM

Cumprimentos:  Carlos Mourato - Sines - Portugal

Best regards from:  Carlos Mourato - Sines - Portugal

Visite o meu canal Youtube em:

http://www.youtube.com/user/CT4RK?feature=guide 

Visit my youtube channel at:

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[Antonio Matias]

Interessante a analise aos Amplificadores Lineares 

73

No dia 24 de junho de 2015 às 13:49, Rodrigo <ct1...@gmail.com> escreveu:

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[Rodrigo]

Boas,

Aqui estão os argumentos do Rob Sherwood e os contra do Bob Allison (WB1GCM) da ARRL.

Argumentos muito técnicos, mas que vale a pena ler.

Tudo isto no forum para o ELECRAFT K-3.

Re: ARRL QST Magazine Product Reviews July 2015
Wed Jun 24, 2015 8:16 am (PDT) . Posted by:
"Rob Sherwood." nc0b
Jim,

Thank you for forwarding Bob Allison’s comments. That is very helpful and I stand corrected in that he only uses as narrow a spectrum analyzer resolution as need for the measurement. Of course that is logical since once the analyzer resolution bandwidth is down to 50, 20 or 2 Hz, the more tedious and time consuming the measurement. All that is needed is to eliminate as much of the phase noise as needed so the IMD product can be set equal to the third signal generator that has been adjusted to the previously-measured noise floor value.

As Bob says, the lowest of the three measurements the League makes is the dominant value. In the case of the KX3 that followed the April 2012 measurements of the IC-9100, the Elecraft transceiver may have been the first product in a long time that didn’t need a spectrum analyzer to make the dynamic-range (DR3) measurement. RMDR was more than 10 dB above DR3.

My test of the new K3 synthesizer in February was made with just an RMS meter and both 400-Hz and 200-Hz roofing and DSP filtering. While I have made a few measurements Bob’s way just for correlation purposes between our two labs, I no longer make any measurements by removing phase noise. A footnote for my dynamic-range measurements will clarify whether the third-order product was the limit or phase noise.

Of course Bob pointed out in the review of the KX3 that being a direct conversion radio, the image was the dominant limitation. I also measured 72 dB at the image null point, though the average over the SSB passband was in the mid 60s. Just an aside, I have used a KX3 in two 160-meter CW contests (W1BB 2012 and CQWW 160 2015), and never observed an image signal. I would expect an image to tune backwards. In November of 2014 I operated the KX3 from Easter Island on 10 and 15 meters. It wasn’t an DXpedition, just enjoying QRP while on vacation.

73,
Rob
NC0B

From: Elecr...@yahoogroups.com [mailto:Elecr...@yahoogroups.com]
Sent: Wednesday, June 24, 2015 5:55 AM
To: Elecr...@yahoogroups.com
Subject: [Elecraft_K3] ARRL QST Magazine Product Reviews July 2015


Just passing this along!

’73 de JIM N2ZZ

----------------------------------------------------------

"Most of what Rob says is true, but I'd like to clarify that we do not use a 1 Hz filter on our audio signal analyzer 99.9% of the time. With 3 IMD DR, most of the time. the span of the audio used to look at the IMD and desired audio signal is not critical. I can use a bandwidth of 500 Hz if I wish, but I usually use a span of 100 Hz (as stated in out procedure manual) , for visual purposes. If reciprocal mixing is severe, I will narrow this span to 50 Hz or 25 Hz. There has been an occasion or two when this measurement became noise limited simply because the reciprocal mixing was too high.

It is only with the blocking Gain Compression Dynamic Range measurement that I sometimes have to narrow down the span of the signal analyzer to a narrower bandwidth. Most of the time, the analyzer bandwidth is left at 100 Hz, but only if the reciprocal mixing is high do I narrow down the bandwidth, usually to 50 or 20 Hz. I have on occasion, used 2 Hz, but doing so makes the measurement process incredibly slow. However silly this may seem, it is done purely to get the blocking figure.

With the classic receivers, reciprocal mixing was the most limiting factor of a receiver, which Rob has always pointed out. Measurement methods have improved for certain. These days, I suggest looking at all three dynamic ranges we measure and pick the lowest one. The lowest dynamic range at a 2 kHz spacing is the dynamic range of the receiver."

Rob, please keep up the good work; you are a great help to all of us.

Bob Allison
WB1GCM
ARRL Senior Test Engineer

----------------------------------------------------------

From: Elecr...@yahoogroups.com<mailto:Elecr...@yahoogroups.com> [mailto:Elecr...@yahoogroups.com]
Sent: Tuesday, June 23, 2015 9:25 PM
To: 'Elecr...@yahoogroups.com'
Subject: [Bulk] RE: [Elecraft_K3] ARRL QST Magazine Product Reviews July 2015

Don’t forget that dynamic-range data (DR3) from QST product reviews from 2007 forward is measured in such a way to eliminate phase noise (reciprocal mixing). A few radios don’t have a phase noise limitation for all practical purposes, such as the Flex 6700, the KX3 or now the K3S.

In 2007 the League decided to make third-order dynamic-range measurements using a 1-Hz filter with an FFT audio spectrum analyzer. Once the League started publishing RMDR (reciprocal mixing dynamic range), you can see how their classic DR3 values can be misleading. RMDR started being published in April 2012 with the IC-9100 product review, but sputtered with the December 2012 review of the KX3 (which has no RMDR problem) and the FTdx-3000 in April 2013. (The color graphics were missing from the magazine.)

The FTdx-3000 QST DR3 published number (with the 1-Hz filter) was 100 dB, but the RMDR in QST was 82 dB (the same value I published on my web site).

Prior to 2007 the League only used DR3 values measured with a 500-Hz CW filter and a wide-band RMS volt meter. If phase noise was the limit, the QST numbers back then were simply listed as “phase noise limited”. Comparing Pre 2007 numbers against 2007 and later numbers is usually misleading, or at least confusing.

IC-9100 has a 2-kHz DR3 value in QST of 87 dB (measured with a 1-Hz filter), but an RMDR value of 77 dB. In the real world the 77 dB number dominates. Who cares what number a lab gets when using a 1-Hz filter since no one uses a 1-Hz filter on the air.

The 1-Hz data is of use to the design engineer. If the third-order distortion products are covered up by phase noise, there is no point in the OEM spending any more time on his mixers. The OME should then spend time and money on the local oscillator (LO) portion of his radio.

Rob Sherwood
NC0B


From: Elecr...@yahoogroups.com<mailto:Elecr...@yahoogroups.com> [mailto:Elecr...@yahoogroups.com]
Sent: Tuesday, June 23, 2015 6:33 PM
To: Elecr...@yahoogroups.com<mailto:Elecr...@yahoogroups.com>
Subject: Re: [Elecraft_K3] ARRL QST Magazine Product Reviews July 2015



One thing to remember, Hans does not abstract data from the transmitted
bandwidth graphs. The K3S, with the new synthesizer, will be quite a
bit cleaner than any of the other rigs listed.

73,

... Joe, W4TV

On 2015-06-23 7:16 PM, Wayne Burdick n6...@elecraft.com<mailto:n6...@elecraft.com> [Elecraft_K3] wrote:
> Bob (K7TM) wrote:
>
>> Interesting table on rig comparisons. I wonder how the K3S with
>> the updates will compare.
>
> Hi Bob,
>
> There should be a few differences.
>
> RMDR (reciprocal mixing dynamic range) was not measured by the ARRL
> in its reviews circa 2009 when they first tested the K3. Since the
> K3S comes with the new synth (KSYN3A), the RMDR should come in around
> 120 dB at 20 kHz and a few dB lower at 2 kHz. This would be
> approximately on par with the best receivers in Hans's chart.
>
> (It's also about 10-15 dB better than that of the radio listed at the
> top. The latter might be explained by that radio's use of a DDS
> without a PLL in its synth.)
>
> The only other recent measurement of a K3 with the new synth that I
> know of was done by Rob Sherwood, and he shows the 2-kHz IMDDR3
> coming in at 107 dB. That is the criteria Hans sorted his chart on,
> and it would have put that K3 at #2. A K3S should be similar.
>
> Another parameter that would improve dramatically is preamp-on MDS on
> 12/10/6 meters (about -145 dBm for preamp 2, also standard with the
> K3S). This is not one of the categories Hans used in his table,
> however.
>
> One thing to keep in mind is that any radio near the top of this
> chart will have "excellent" dynamic range, and a dB here or there is
> really not going to be noticeable on the air. A lot more noticeable
> is the incredible range of prices for radios in the chart. I like the
> "dynamic dollar range" comparison between the #10 radio (Hiberling,
> $17,500) and the #11 radio (Elecraft KX3, $999 assembled, $899 kit
> :)
>
> 73, Wayne N6KR
  
>>
>> On Tue, Jun 23, 2015 at 1:57 AM, Hans Remeeus ha...@remeeus.eu<mailto:ha...@remeeus.eu>
>> [Elecraft_K3] <Elecr...@yahoogroups.com<mailto:Elecr...@yahoogroups.com>> wrote:
>>
>>
>> Dear groupmembers,
>>
>> Today I published a recent overview of the ARRL QST Magazine
>> Product Reviews July 2015 on my website:
>>
>> http://www.remeeus.eu/hamradio/pa1hr/productreview.htm
>>
>> In which you will find the Key Measurements Summary of 41
>> HF-Transceivers or Receivers Product Reviews, published in QST
>> Magazine between 2006 and 2015.
>>
>> Please send me an e-mail if you have any comment or question.
>>
>> Please widely pass this message through, if you want.
>>
>> Many thanks and 73! Hans.
 

Copiado do forum K...@yahoogroups.com

73

Rodrigo

ct1bxt

[Pinto]

Bom dia Rodrigo, e companhia.

Da próxima faz um favor aos “pitosgas” aumenta lá um pouquinho ao tamanho dos caracteres, caso contrario fica-mos sem ler os teus sempre interessantes assuntos.

Muito obrigado

Pinto

[Rodrigo]

Ola Pinto,

Desculpa, mas não me apercebi do caso.

Não voltará acontecer.

Rodrigo