6600 Sherwood racking

Marc Lalonde

Hi 

since is see no one raise the interrogation ,i do it 

if my memory is good ,as continuous performance improvement  the new radio generation was announced whit similar or better performance that previous generation  6500/6700 ,that was a key sale point  

so now that ROB update it listing whit radio that got all the PCN , 12 place result was quite 
deceptive ? , honestly anything more that 4th place was deception for that new generation 
old plain analog radio is better ranked ;-) 

on my side i may tell that yes on EME operation i see a really noticeable difference in operation
whit respect on my old 6700  ,and still evaluated idea to swap back to 6700

please try to keep that tread constructive whit no flex bashing  ,critic is good basing is not 

Marc L. VE2PN/VE2OLM

Gerald-K5SDR

Hi Marc,
With respect, I am not sure I understand your question.  What specifically are you asking? 
73,
Gerald

k0eoo

Rob just put the 6600M out on his receiver performance page....

Steve

I think what Marc is saying is that IF the 6600M  has been touted as a better performing radio then why is it lower than the 6700 on Sherwood's list.      The question is when does a SMALL "measured" difference in dynamic range even become noticeable in day to day operation of a radio??  Also at what level of measurement is dynamic range  as good as it NEEDS to be.  I suspect that anything above a certain point is as good as it needs to be.  Also Rob has stated there are some caveats to his measurements.  
  

Gerald-K5SDR

Rob has publicly stated many times that you won't notice a difference between radios that measure either 90 dB or 100 dB of IMD3 dynamic range.  He is quoted in another thread on this community saying that.  The 6600 is a ~100 dB radio plus or minus in IMD DR.  RMDR is >115 dB with the new enhancements installed.  

Robert Lonn

I have the 2nd ranked Icom IC-R8600, I also have the 6600M.. The Icom is a true SDR below 30 MHz, above that it is triple conversion,, so in comparison I stayed below 30 MHz.. I also have a JRC NRD-545, Drake R8B, Routers RDR50  $3K SDR receiver to compare them to.. 

The 6600M can hear what the others can not.. The RDR50 was the best receiver till I got the 6600M. The audio just sounds better, more intelligible audio on weak signals,, and I never could imagine that regular SSB reception could sound almost like I was listening to Wideband AM audio.. SSB is one of those things that you can never get the station tuned in perfectly, but the Flex does that with ease,, basically is can recover the audio with clarity and fidelity..

My RDR50 receiver will beat out the Icom R8600 receiver and the 6600M beats both of them on recovered audio.. Not sure how it got so high on the list, but Bob does a good job with his measurements,, but my ears dont fool me to often..  I hope to do some comparison videos in the future showing the RDR50, R8600 and 6600M in a comparison test..

Robert
WA6PHN

Robert Lonn

Gerald,, what do you mean by New Enhancements Installed??

Rich McCabe

Yes, I am curious too. What the 3 hardware updates are.

Marc Lalonde

Hi Gerald  , it more a observation that a plain question 

Marc Lalonde

in SSB on HF it quite hard to see difference ,since radio is way much better that band condition   

but on some special case like in EME operation number start to really matter ,you trying to decode signal -28 db under noise a few khz away for pager tower  ,APRS and 2m  repeater and so on ...   on my case i notice that my 6600 is much more susceptible to intermod  ,and dynamic range whit +32db is less that 6700 whit +40db pream on  , i no longer receive my  echo  back from moon and signal seem to dropped for 5-6 or more db in general ,when work whit signal ranging from -16 to -28db is really noticeable !   ,hope that PEN will fix that 

Gerald-K5SDR

Everything is described in the Product Enhancement Notification (PEN) that went out by email yesterday to those to whom it applies.  There are two hardware updates that are described for the 6400/6600 models shipped before April 12, 2018.   One is recommended and can be customer installed and the other optional.  Tim also posted the link in a thread on the Community.

Gerald-K5SDR

Robert, 
This is a VERY frequent comment we get, especially from contest who listen for hours.  Too bad Sherwood doesn't have measurements for in band distortion and recovered audio.  Those make more difference in most operating environments than the current ranking system.  
Gerald

Robert Lonn

When radios first hit production, I am sure that some minor hardware issues were discovered in QC and then corrected. If Bob Sherwood got a first production unit,, it may have not been a final production model,, And his  posted evaluation may have been done with a late production run.. Same thing with the Icom IC-R8600, Bob listed a 2nd receiver, later production that performed better then his first test.,,, sometimes 90% of this is software driven. 
The bottom line is that Flex backs everything 100%, These are Very High Tech receivers,,, Sometimes you just need a few months to work out the bugs.. 

BTW, 6 meters has been open the last month, if you have not tuned your Flex up to 6 meters, give it a try, your in for a big surprise,, your antenna may not be able to TX with but you can listen with most antennas tuned to the HF bands.

Robert

Gerald-K5SDR

Marc,

Are you using the same transverter on the 6600 and 6700 when on EME? 

How much RX gain is in the transverter? 

What is the signal spacing between your receiver and the interfering TX signal? 

How far is your EME antenna from the pager tower?  Is it pointing toward the tower?

Gerald

Rich McCabe

Since Rob says "3 Hardware Upgrades", I am doubting that is the case.

Gerald-K5SDR

Rob is mistaken about "3 Hardware Upgrades."  There is one recommended and one optional hardware upgrade.  This information is in the notice sent yesterday.  I will contact Rob to make sure he understands.  I did check and the unit Rob tested came off the line in the first two weeks of production shipments.

Ken - NM9P

Listening to the Flex with a pair quality speakers is a pure pleasure.  Full, rich, articulate, and much less background noise than most other rigs.  Indeed, the reduced "fatigue factor" is huge!

Matt NQ6N

My interpretation of the PEN announcement and the comments I read yesterday is that perhaps the biggest factor in the Sherwood ranking difference between the 6600 and 6700 is that the 6600 does not yet have a firmware update (which has already been released for the 6700) that will provide a bit of additional dynamic range in strong signal conditions (such as Sherwood's test setup). 

So I would guess that a 6600/6600M with the firmware update AND PEM updates will rise in the Sherwood rankings.   Note that the Sherwood rankings for the various tests of the 6700 do not seem to indicate whether the firmware update was installed, so it's not clear what impact it had on the results in the various tests. 

Compared to other high end rigs I've used, the 6600's receiver sounds fantastic and the close-in dynamic range makes a crowded 40m CW segment feel like there's plenty of room for everyone, signals sound clear and pure, and weak ones are copyable without the typical audio artifacts introduced by other rigs' filters.   Also, the Sherwood tests do not really cover one of the most useful aspects of the 6600's receiver design which is contest band bandpass filtering suitable for full duplex operation. 

73,
Matt NQ6N

Marc Lalonde

same setup as whit 6700 

kuhne MKU 144 G2 whit 25db conversion gain 
WA2ODO "ultra narrow" preamp  whit 0.122db noise figure @27db gain
whit 2MHZ wide DCI bandpass filter in front on LNA

i have make lot of bench test whit the 6700 and find that 144 XVTR VS the kuhne transverter have 1-2 db loss of signal  , both permit to got good echo back 

for avoid urban noise i limit my operation only when moon is above 10-15 deg elevation  

Best regard 

Gerald-K5SDR

Marc, 

1. What is your total system gain?
2. What is the signal strength of the interfering signal?
3. What is the frequency spacing from the interfering signal to your passband?

Gerald

Robert Lonn

I probably listen more than I TX... That is because I am on my desk computer doing work related stuff with the radios on in the background... So I dont like to get listening fatigue. The Flex recovers audio better then even my Drake R8B, and that was a radio known for great audio fidelity... I have the Flex hooked up to a Sony Classic- Vintage amplifier driving a Hallicrafters Speaker.. Amazing Audio Quality!!! Two Speakers for Stereo MONO Audio! LOL

Marc Lalonde

Gerald 

measure precise system parameter of remote mountain top  site is not easy 

but before install system i measure on bench signal to noise ratio of the system whit calibrated signal generator (Agilen ESG-D4000A ) and precision mini-circuit attenuator  for make signal to noise testing and and to XVRT port isolation  and notice a small degradation VS the 6700  ,but as i trade it i cannot redo A B test

since snow melt i only have go onsite one ,so more test is planed  and hope PCN will help
but operation LOG since i put 6600 on air clearly show 5-6db signal loss somewhere and more intermod ,i wait to have more bench testing before check for a help-desk ticket or else

the 100khz blocking range may a clue ,no sure yet

p.s. i see only 2 mod on the PCB  , heatshink and ,cap on LDO  not 3 as Sherwood said ?

Best regard 
Marc VE2PN/ VE2OLM




 

Ria

2.2.8 was released today. I believe that contains the software update.

Gerald-K5SDR

Marc,

What is your total cascaded system gain from the antenna through the radio?  In other words, do you have the preamp at the antenna and how much gain.  How much signal loss in the coax? How much gain in the transverter?  How much gain in the receiver?  What IF frequency are you using?

Sherwood is mistaken.  There are only 2 modifications.  

Gerald

Marc Lalonde

Hi  it ~75db gain whit 28mhz IF   
23.27dBi for antenna stack , 27db for LNA  and 25db for transverter  , loss from antenna to LNA  is under 0.5db including commector , pahsing line  ,power divider)

this not include the radio +40db of additional gain

Best 73!

Gerald-K5SDR

So are you saying that you are using 115 dB of total system gain including the radio preamps?  That is 92 dB of analog gain between the antenna and the ADC.
Gerald

Marc Lalonde

75 + 32 look more like 107  ,let said +/-3db since antenna is not in free-space  but may have some ground gain  ,noting extraordinary for EME station ;-)  ,we try to beat ~250db path loss 

Gerald-K5SDR

Marc,
It looks to me that you have far too much system gain.  In fact, less is more to increase dynamic range.  

Here is the cascaded noise figure analysis for your current setup with the 6600 receiver gain set to 24 dB.  Look at the d NF/d NF line and you can see that you cannot improve NF by increasing gain.  You are clearly overloading the receiver with too much system gain.  Let's look next at reducing the gain of the 6600 to see how it affects noise figure.



Below is the same calculation using the -8 dB setting on the 6600.  This increases the overload point of the radio by 32 db but does not desegregate the noise figure at all.  Note that the input NF at the LNA is 0.12 dB in both cases but you have increased dynamic range dramatically.  The radio has zero effect on system NF at any of its gain settings but the higher the receiver gain, the lower the total dynamic range.  It is all about gain distribution.  You could even drop the gain of the Kune some without hurting NF according to the d NF/d Gain row.  That would further improve dynamic range.  

Marc Lalonde

Hi  yup 100% right about noise figure , it determined primary by first stage 
and i agree that for "land" QSO i need to drop gain  , if not it quickly overdrive the ADC 
but for EME  unfortunately i need that gain , just for make really sure will try it back on next moon raise ..   

usually i try to work whit minimum signal need for 10db over noise signal instead of system gain , since true radio gain and antenna is quite hard to knot so make hard to make A vs B testing 

Best regard  , have good trip to Dayton/Xenia

Gerald-K5SDR

Marc,
I may be missing something but more receiver gain does not increase sensitivity unless it is antenna gain or processing gain.  The MDS does not improve with added gain in the receiver.  You can add 1000 dB of receiver gain and the MDS will not improve to better than kTB.  
Gerald

Craig Williams

I love it when the head man takes time out to educate the average Ham.