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Author Topic: Sherwood Engineering Receiver Test Data  (Read 13052 times)
KE5JPP
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« on: August 31, 2012, 05:23:27 AM »

Does anyone know what frequency that Rob Sherwood typically performs his receiver test procedures at?  I assumed it was 14 MHz.  I only saw a couple of radios where he indicated either 20M or 17M (Kenwood TS-590s, for example).

For some radios, it might not make a difference in the test results, but in SDR radios that use a QSD, such as the Flex and the KX3, it is well known that the performance of the QSD degrades greatly above 20 MHz.  It would be interesting to see if the KX3 or Flex Radios hold their places on the list if the receiver testing was done on 10 meters.

Also, the KX3 uses a si570 as its local oscillator.  The phase noise of the si570 degrades the higher in frequency it is used at.  It would be interesting to see the phase noise measurement repeated on 10 meters.

Gene
« Last Edit: August 31, 2012, 05:28:39 AM by KE5JPP » Logged
W4ZV
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« Reply #1 on: August 31, 2012, 05:33:41 AM »

Does anyone know what frequency that Rob Sherwood typically performs his receiver test procedures at?  I assumed it was 14 MHz.  I only saw a couple of radios where he indicated either 20M or 17M (Kenwood TS-590s, for example).

For some radios, it might not make a difference in the test results, but in SDR radios that use a QSD, such as the Flex and the KX3, it is well known that the performance of the QSD degrades greatly above 20 MHz.  It would be interesting to see if the KX3 or Flex Radios hold their places on the list if the receiver testing was done on 10 meters.

Normally 20 meters only.  The reason Sherwood also included 17m is because the TS-580S uses an up-conversion scheme on 10m and all WARC bands (down-conversion on 15m and lower non-WARC bands).  He probably chose 17m since it's close to 20m.  ARRL also uses 20m for most published results, although it adds 80m for some key measurements (e.g. IMDDR3).  I've never seen any test results for 10m by any established testers (e.g. ARRL, RSGB or Sherwood).

73,  Bill
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NI0Z
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« Reply #2 on: August 31, 2012, 06:02:14 AM »

Elcraft just released a beta patch for the KX3 that "I think" might be relevant to your question that allows adjustments by band now.  Some users were quoting radically improvements on other bands than 20M.

I"ll leave it to the experts to dig into it and see if it's relevant or not applicable to this conversation.
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KE5JPP
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« Reply #3 on: August 31, 2012, 06:22:29 AM »

Elcraft just released a beta patch for the KX3 that "I think" might be relevant to your question that allows adjustments by band now.  Some users were quoting radically improvements on other bands than 20M.

I"ll leave it to the experts to dig into it and see if it's relevant or not applicable to this conversation.

It does not appear to be relevant.

Gene
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KE5JPP
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« Reply #4 on: August 31, 2012, 06:53:16 AM »

Interesting Rob Sherwood power point presentation:

http://www.sherweng.com/temp/NC0B-W9DXCC-3a.ppt

Particularly interesting is how BAD the K3 and Flex-5000a transmitters are! (both appear in the top 5 on the receiver list).

Pay attention to the discussion of the poor audio distortion performance in the K3.  This confirms my experience with the K3's crappy, tiring receive audio even with the factory fix.  It's also is the reason that I prefer to listen to my SDR receivers like the QS1R and Perseus, where I have measured the audio distortion at less than 0.1%.  The Flex-5000a also seems to do well as far as audio distortion (slide 52) - but like my SDR receivers, they use an audio DAC (sound card DAC) for audio output.

Gene
« Last Edit: August 31, 2012, 07:17:19 AM by KE5JPP » Logged
NI0Z
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« Reply #5 on: August 31, 2012, 07:27:13 AM »

Doesn't the presentation indicate that the choke fix Elcraft made resolved the issue on the K3?

Here is what I was talking about above.

http://groups.yahoo.com/group/KX3/message/13893

This link here certainly helps make your argument for receive audio.

http://www.cliftonlaboratories.com/elecraft_k3_receive_audio.htm

For all the tests there is just real world usage and the variables they represent.  

So now at the base station my KX3 audio is coming through NAP3 and a 24bit 192K sampling and actually pulls out weaker signals than through the radios base audio hooked to speakers.  

A small informal test last night showed the same weak signal coming out of the KX3 headphone jack to speakers being less perceptible than the Flex 5k through Bose speakers hooked to the PC.  Then running the Kx3 through NAP3 and the sound card and the same Bose speakers the KX3 was much more perceptible than the flex.  The Panadaptors showed the signal about equal burried in the noise floor with maybe an edge to the flex with it looking a micro hair stronger.  I gather that Panadaptor displays like these are not exactly something you can really use to measure signals.

So which way do we want to look at a KX3, through it's direct audio or is SDR audio?  Do we want to go by test equipment or by our ear?

What I am finding is that radios are not nearly as bad as people make them out to be on paper.  It's substantiated by reviews and feedback from the actual users.  Labs are awesome, but the user, not just the lab test, is the end goal isn't it?

The problem with many arguments here is they totally discount the end users experience with their radios.  Lol despite all the damning lab results, they luuuuvvvv their radios.  

Funny isn't it?  How do you account for that?
« Last Edit: August 31, 2012, 08:00:55 AM by NI0Z » Logged

K9IUQ
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« Reply #6 on: August 31, 2012, 08:20:25 AM »


Particularly interesting is how BAD the K3 and Flex-5000a transmitters are! (both appear in the top 5 on the receiver list).

Pay attention to the discussion of the poor audio distortion performance in the K3.  This confirms my experience with the K3's crappy, tiring receive audio even with the factory fix.  
Gene

As noted in another thread I have considered the K-3 in my Shack several different times. The top 2 things that stopped me are the 2 items you just mentioned. The third thing is the poor ergonomics which is well publicized.

Even tho the K-3 is highly regarded by DXers and contesters  I am not going to buy a radio that is fatiquing to listen to. Also I have never heard a K-3 on the air with acceptable (IMO) SSB audio. In spite of W4ZV's spinning of the subject, My ears hear what they hear.

Before I bought the Flex 5K I had many email conversations with Sherwood. What he told me about various radios was eye opening. I was also very surprised when he told me what he owned personally, it was not any radio in his top 10 list.

Since then I pay little attention to RX spec ratings when I buy a radio. The most important factor to me is I have to like and enjoy operating the radio.

Stan K9IUQ


« Last Edit: August 31, 2012, 08:34:37 AM by K9IUQ » Logged
KE5JPP
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« Reply #7 on: August 31, 2012, 08:53:30 AM »

Doesn't the presentation indicate that the choke fix Elcraft made resolved the issue on the K3?

The choke fix did help the problem.  Unfortunately, not enough though.  There are other issues at play, like the AGC response and DSP artifacts that also make the K3 tiring to listen to.  If I was just a contester and only used my radio in contests, I'd probably have a K3.  However, I want to use my radio for other things than just contesting - one of my criteria for a radio is that it must have excellent general coverage receive, not just the Ham bands.  It must not be fatiguing to listen to for long periods of time.  It must not be frustrating to use for long periods of time - such as having almost every setting behind a inconvenient menu system that only a software engineer could appreciate.

Quote from: NI0Z
What I am finding is that radios are not nearly as bad as people make them out to be on paper.  It's substantiated by reviews and feedback from the actual users.  Labs are awesome, but the user, not just the lab test, is the end goal isn't it?

The problem with many arguments here is they totally discount the end users experience with their radios.  Lol despite all the damning lab results, they luuuuvvvv their radios.  

Funny isn't it?  How do you account for that?

Many people think that the radio they have spent their money on is the best, it is too much of a blow to the ego to admit otherwise.  eHam reviews are the last thing you want to base your purchasing decision on.  Actual operating experience with a particular radio, in they way you intend to use it, is the only real way of knowing for yourself.

What people do is use the Sherwood list to justify their purchase of a particular radio when that radio is towards the top of the list.  They feel it gives them bragging rights - after all Sherwood says my KX3, or K3, or whatever is the "best radio out there".  When their radio is not high on the list, they use other reasons to justify their purchase.   But what I have repeated many times on eHam is that the Sherwood tests do not tell you that a particular radio "is the best" like many guys think it does.  You have to take into account the whole operating experience - ergonomics, ease of use, price vs what comes standard on the radio, accessory costs, price to performance ratios, etc...  

There is not a day that goes by lately when I don't here some Hams on the air talking about how the KX3 is the best radio out there because it is on the top of the Sherwood list.  One OM actually said that he intended to sell his FTdx-5K and replace it with a KX3 when Elecraft comes out with the 100 Watt amplifier because the KX3 "is the best on the list"!   Shocked  All this OM does with his rig is rag chews to his buddies on 40 meters - no contesting, no Dx, no CW!

Gene
« Last Edit: August 31, 2012, 09:10:33 AM by KE5JPP » Logged
NI0Z
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« Reply #8 on: August 31, 2012, 09:41:35 AM »


Many people think that the radio they have spent their money on is the best, it is too much of a blow to the ego to admit otherwise.  eHam reviews are the last thing you want to base your purchasing decision on.

What people do is use the Sherwood list to justify their purchase of a particular radio when that radio is towards the top of the list.  They feel it gives them bragging rights - after all Sherwood says my KX3, or K3, or whatever is the "best radio out there".  When their radio is not high on the list, they use other reasons to justify their purchase.   But what I have repeated many times on eHam is that the Sherwood tests do not tell you that a particular radio "is the best" like many guys think it does.  You have to take into account the whole operating experience - ergonomics, ease of use, price vs what comes standard on the radio, accessory costs, price to performance ratios, etc...   There is not a day that goes by lately when I don't here some Hams on the air talking about how the KX3 is the best radio out there because it is on the top of the Sherwood list.  Once OM actually said that he intended to sell his FTdx-5K and replace it with a KX3 when Elecraft comes out with the 100 Watt amplifier because the KX3 "is the best on the list"!   Shocked

Gene


Gene, I do believe you have a point here, I saw it all the time with cameras on photography forums, I called it the specs wars.  The funny thing was it was easy to see who were really good photographers and who were really not as the cameras were all good enough that the camera was not making the difference.

I have to tell you though, I was amazed last night at how well I had the little KX3 running.  I almost have it fully integrated as a base station.  Pretty sweet having a nice Panadaptor display, high quality audio and then being able to reach over to the knobs on the radio itself and operate like any other radio with a full set of controls.

I get it, some people out there don't like Elecraft controls.. No need to tell me that.  But I am must be one of those software engineer types so your dislikes are not mine and they won't be for everyone else either.  240-260 watts out as well, no added 100 watt amp, just the one I already have.  It was a really nice operating experience for sure!  I plan on pushing forward integrating it the rest of the way as well.  Not bad for just a few hours of actual time I had available to play arou d with it.

These radios can be like having 3 radios if you look at it the way I do.  If I had a FT5000 though, I doubt I would sell it away for a KX3.  Time will tell if it can replace the flex.  It's such a small rig though and I still have some things to get used to in a mixed user interface paradigm.
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KE5JPP
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« Reply #9 on: August 31, 2012, 10:17:51 AM »

I get it, some people out there don't like Elecraft controls.. No need to tell me that.  But I am must be one of those software engineer types so your dislikes are not mine and they won't be for everyone else either.  240-260 watts out as well, no added 100 watt amp, just the one I already have.  It was a really nice operating experience for sure!  I plan on pushing forward integrating it the rest of the way as well.  Not bad for just a few hours of actual time I had available to play arou d with it.

How long have you had your KX3?  I am sure not long enough to get tired of the menu arrangement on the KX3.  It is OK for a portable radio, but no matter how much you might initially like the menu system, if you have to use it day in and day out, it gets irritating compared to a radio that has those same functions in a dedicated button on the front panel.

Gene

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KE5JPP
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« Reply #10 on: August 31, 2012, 10:27:17 AM »

It is interesting to note that without the optional $129.95 roofing filter, the KX3's 2kHz narrow spaced dynamic range (the spec that puts it at the top of the list because Sherwood sorts on that item) is no better than the Flex5k and worse than the Perseus.  If you use the optional $129.95 roofing filter, your panadapter view becomes very narrow.

It is pretty clear that if Flex would have made it possible to have an option to add an I/Q roofing filter (like the KX3), the 2 kHz DR would be right up there with the KX3 at least.

The other thing is the Perseus beats the KX3 DR if the KX3 does not have the optional I/Q roofing filter added.  Putting a narrow tunable filter in front of the Perseus ADC would push the DR number up over the KX3, putting it at the top of the list.

Gene
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NI0Z
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« Reply #11 on: August 31, 2012, 10:38:16 AM »

 I did buy the roofing filter.  Works great!  The whole setup is quite amazing!  I will have update 3 on the blog later today.  Last night it all came together! 

I seriously don't get the menu thing though, what's in those menus that you would be going in so frequently that would be the bother?  Also, it's all in alphabetical order and a breeze to zip through?

I am pretty much a set it and go kind of guy, so other than band switching and basic filters which are on the front already, including notch, NB, NR, gain controls for AF/RF, filter width knobs, ect..  What am I missing Gene.. Seriously I am asking, I don't get it..  I hardly even use filters on the flex either, most times they don't help much.  I used the notch last night on the KX3, worked great.  What's in those menus that a user is going to access frequently while operating?
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KE5JPP
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« Reply #12 on: August 31, 2012, 12:10:47 PM »

I did buy the roofing filter.  Works great!  The whole setup is quite amazing!  I will have update 3 on the blog later today.  Last night it all came together!  

I seriously don't get the menu thing though, what's in those menus that you would be going in so frequently that would be the bother?  Also, it's all in alphabetical order and a breeze to zip through?

I am pretty much a set it and go kind of guy, so other than band switching and basic filters which are on the front already, including notch, NB, NR, gain controls for AF/RF, filter width knobs, ect..  What am I missing Gene.. Seriously I am asking, I don't get it..  I hardly even use filters on the flex either, most times they don't help much.  I used the notch last night on the KX3, worked great.  What's in those menus that a user is going to access frequently while operating?

CW settings, AGC settings, RX eq, AFX, plenty of others if you wish to pull out weak signals in a crowded, noisy band.  You will see as you get more experience operating.

While the menu system may be alphabetical, just having to enter the menu settings when you are trying to catch a weak signal to tweak the settings gets to be a PIA after a while.

Gene
« Last Edit: August 31, 2012, 12:16:40 PM by KE5JPP » Logged
NI0Z
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« Reply #13 on: August 31, 2012, 02:29:54 PM »

Interesting, those all look like infrequently changed items to me.  Like setting up your CW paddle, turning manual AGC control on and or off so you can control it from the front panel, stereo on or off, ect.

I guess they will mean more to me later.

Thanks for answering the question.
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N5RWJ
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« Reply #14 on: August 31, 2012, 02:43:47 PM »

What's up with the speaker hum?
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