Pages: 1 2 3 4 [5] 6 7 8   Go Down

Author Topic: Choosing a rig and Sherwood's list  (Read 4720 times)

K4FMH

  • Member
  • Posts: 681
Re: Choosing a rig and Sherwood's list
« Reply #60 on: April 11, 2021, 05:26:42 PM »

Mike, et al,
Remember, I love Rob!   He has so much for ham radio, he should get a lifetime achievement award!
(especially from those who love R.L. Drake products!)

But, of course it's not just the top 50 radios on the list that will outperform the operators and locations...

I would add the first 50 radios will outperform not only the operators but the locations by at least 20 dB.

In my opinion, except for a few inexpensive "shortwave receivers" and a couple old clunkers (like an FT-101, or SB-303), just about every radio on Rob's list will perform adequately for most hams these days....
Heck, my first HF ham contacts (as a "3rd party", before I was licensed) in the early/mid 70's were on some old Collins gear at BCC, and a friends new TS-520....and, with todays modern RFI issues and HOA-restricted antenna systems, even the old TS-520 will still make lots of contacts!  :)


And, the "top 50" or more, will do well in just about any situation, except for serious CW contesting....


Bottom Line:
....so, if I could only contribute two or three quick pieces of advice to share with my fellow hams in regards to what rig to choose, they would be these:

a)  Choose a radio that you actually like using!  One that is easy to listen to and easy-to-use, etc!

b)  Choose a radio that meets your own needs, not what someone else says they need!

c)  Choose a radio whose transmitter is clean!   Just like not polluting our waterways, nor our land, nor our air....take some pride and don't pollute the airwaves with useless emissions that harm everyone!

Hmmm...I wonder if anyone will notice that I don't mention any "numbers" or "specs"?

Of course, there is a lot more (just read the postings above), but if I only had 15 to 20 seconds and a few sentences, those 3 would be it!


73,

John,  KA4WJA

John,

I second your nomination of Rob for a lifetime achievement award!

Take a look at my attempt to build upon Rob’s measurements, putting ALL 9 of them into a single rig Rx index, and relate them to price and satisfaction:

https://foxmikehotel.com/hamography/studies/

See the full study linked on the above page and the edited versions published in NCJ in two parts.

73,

Frank
K4FMH
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #61 on: April 15, 2021, 10:36:23 AM »

Frank,
1)  Thank you for all that hard work!!

And, yes Rob's list is a nice resource for us (and again, I think he's great)....but, I still think this fascination for / concentration on a "list" is mostly folly for most hams.....(yeah, it's great to see what's out-there and how it performs....but, for most it's just a dream....and, I'm planning on a rather lengthy post describing my own personal rig choices / criteria, over the past ~ 45 - 50 years, with explanation / reasons for the choices, so while it won't be a statistical analysis, and it didn't use Rob's list, I do hope some will find it useful?)

As I, and many others (including Rob Sherwood, himself), have been saying for years:  The list is just a list, and is not a way to choose a radio, as there are many other criteria! (see my earlier posts here, for quotes from Rob, etc.)  Rob does this testing, and assembles the "list" by narrow-spaced rec IMD3 results, in order to best organize a list of radios that can serve well in tight/crowded/competitive CW Contest conditions, primarily for big-guns with big antennas, etc...and, important to understand that some of the measurements are a bit moot for most hams, as some are geared towards those out-in-the-middle-of-nowhere, in "quiet rural" RF locations....with large directional antennas, and/or some measurements are similar for most modern radios, these days...

Anyone else using the "list" to choose a rig, is.....well, they're probably wasting time and money....and as long as they understand this, that's cool / no worries!  :)

A case on-point, of someone that does understand the limitations of their station location and the particulars of "the list":  I know a gentleman, in a "planned-community", in a zero-lot-line townhouse, who loves 75m rag chewing.....but has been unable to get a decent 80m horz antenna up, but has gotten a small vertical up (and quite a few short radials), and has a big OM Power amp (a tetrode amp, that is sensitive to ALC spikes / overdrive)....who tried an FTdx-101d (you know, It topped the list, so he thought it would be great)....he was never able to use all of what that receiver could do, but no matter he has the $$$$ to spend....BUT.....but, he splattered (buckshot up/down the band) so bad (even his friends were telling him so) with the ALC issues of that 101d, combined with the tetrode amp, that he gave up....he now uses an ANAN (with its pre-distortion) and is MUCH happier....of course he still can't use all that the ANAN can do, but he loves it and he no longer splatters, so all is good!


2)  But, there are guys with end-fed-half-waves, with lossy feed baluns/unun's, strung up 15' high, in suburban lots, etc. that are spending 1000's of $$$$ on rigs at (or near) the top of "the list"....and in my opinion, that is folly!  :(

On the opposite end of the spectrum, are the big-guns with stacked-yagis on multiple towers, 8-circle rec arrays, etc.....and the big Multi-Multi stations with as many as a dozen operating positions and as many towers as national forests have trees!   But, even these guys can get by with a middle-of-the-pack HF rig for SSB operations...although the Multi-Multi guys do need to assure clean transmitters....of course for serious CW contesting, this is where the "narrow-spaced rec IMD3 spec" and the "narrow-spaced RMDR spec", is paramount....and, hence "the list"!


3)  When I read your post, I thought "cool!".....then I saw it was a statistical analysis, and thought "oh no"....(you see, while I majored in Physics, I actually dropped a "Stats" class, after the drop date, 'cuz I just couldn't take it, made my head hurt :), but, I have a LOT of respect for those that are great statistical analysts...)

When I read thru what you did, I found it interesting....but, to be honest there are data points (specs on Rob's list) that all but irrelevant and may be interfering with the final analysis?  Maybe I'm wrong and your analysis isn't effect by them, but thought you may be interested in some further insight (heck, it might spur you to do another analysis)...

As well as my concern using eham reviews as accurate data.....now, I love eham, but when someone spends their dollars on something, especially lots of $$$$, especially on something as big of a deal as a new HF rig, I find reviews to be "questionable" data...

But, my only serious concern is that (except for the 30 rigs in the top quartile) we can only see the "top 10" and "bottom 10".....when it's the middle-of-the-pack on the list, that are the radios most often used, and most often compared...


4)  Frank, while I do applaud you for doing this, in my opinion using some of those test categories / measurements to try to correlate into one index (the "SPI"), might be a problem....(maybe not, but let me explain....remember that many of his measurements are rather moot for most hams, as they are geared towards those out-in-the-middle-of-nowhere, in "quiet rural" RF locations....with large directional antennas....not for the "average ham")

Look at what Rob, himself, writes in describing the different measurements....or even better, read what I write here, to see what are the really important measurements to look at / do a stat analysis of...(you only need 5 or 6...of course if your really want to do a stat analysis of HF rigs, have a look at their occupied bandwidth / transmit IMD... :) )

HF Rec Noise Floor, Sensitivity, and AGC Threshold, are numbers that, for all practical purposes, you could leave out of the calculations.

a)  Regarding the "Noise Floor" (3dbMDS=Minimum Discernible Signal with 3db S/N), spec (in a 500hz, CW Bandwidth), unless someone has their station out in the middle of nowhere, in a very RF "quiet rural" area, there is little chance of anyone ever having ambient noise floor as low as most receivers noise floors (especially on 15m and below)...so, this spec is rather moot these days.

b)  And while "sensitivity" spec is based on a 10db S+N/N (in a 2.4khz "SSB" Bandwidth), just as with the actual rec noise floor spec (done with a 3db S/N), all HF ham rigs made in the past 40 - 50 years have plenty of "sensitivity" and can make a 10db S/N with no issues, at "sub-micorvolt levels"...so this spec is also rather moot now-a-days.

c)  AGC Threshold changes as you vary the RF Gain (and/or switch on-off pre-amps and/or attenuators).....and after the VFO, the RF Gain is the next most often used control on an HF ham rig....so, while actual AGC operation, making sure it doesn't "pump", or doesn't respond to very short noise pulses (something many modern radios do!), are very important....these days taking an AGC Threshold measurement into the heap of numbers to compile an "SPI", seems rather moot as well.


d)  Front-end selectivity spec....well, this is a judgement call whether you include this spec or not, I mean, it is an important spec, but since almost all modern radios (made in the past 40 - 45 years) have adequate RF selectivity, this spec has just about passed it's usefulness to be included in a statistical analysis.....but, probably won't effect the results...


5)  And, how do "weigh" the other specs?  What priority do you place on them?  Or should we even try to place them in some priority (probably not)?

Those are great questions, and the answers are:  "it depends".... :)

Most of all, It depends on what the application is....as we all know, for the average HF casual SSB rag chewing ham, in suburban areas, etc....anything except the very bottom few on the list will work!  Heck, there are still guys yacking away on FT-101's (9th from the bottom) and TS-520's (19th from the bottom), now they unlikely to be winning contests with them, but casual HF SSB rag chews are no problem....

Of course the "Narrow-spaced Dynamic Range" spec, and the "Wide-spaced Dynamic Range" spec are what everyone raves about (and are the meat of "the list"), but in my opinion when looking at the list (other than transmit IMD, ergonomics, reliability, easy-to-listen to, etc.) "Phase Noise", "Blocking Dynamic Range", and "Ultimate Filter", are the additional things to put into a statistical analysis.  And, I'd add RMDR, as well....which can be approximated by subtracting 27 from the "phase noise" spec in Rob's list...

Some might question whether "Blocking DR" and "Ultimate Filter rejection", should be included in a statistical analysis, but I say yes....Blocking DR is an important spec to see how strong of a signal a rec can actually handle without desense or overloading, which is important to many hams these days, not to mention important if using a rec as a "monitor receiver" and/or using a separate rec, and/or a separate rec with separate rec antenna, etc. etc... and of course "Ultimate Filter" is still an important spec for a lot of hams, especially those in crowded locations/bands, etc. and especially if in a multi-multi situation, and/or also if the rec has low-phase noise (otherwise any rig attempting "ultimate filter rejection" over ~ 90db, you're not likely to ever see that, as you'd be seeing phase noise distortion products....i.e. from reciprocal mixing of the signals with the noise of the oscillators)....older rigs with low "ultimate filter" specs are usually from filter blow-by....so, again, while this is an important spec for some, and I do think it should be included in a statistical analysis study, it can be confusing to some...

So, is it even possible to qualify / prioritize these specs and have everyone be able to use a SPI?  Possibly yes...

And, we come back to what we have now....we have a "list" of some RECEIVE specs (NOT transmit specs), that are cool to know, and nice for some to quasi-evaluate some rigs against each other, but only significantly useful to a select few hams (serious CW contesters, in particular)...


6)  Now throw into the mix personal reviews (eham, or others?) of various radios.....and you have many reviews from folks who have little HF experience (many HF operators these days run everywhere with the RF Gain cranked all-the-way-up....and/or always have a pre-amp on...etc.), and even those with experience and/or knowledge, some are hindered by antenna restrictions, neighborhood RFI, etc. that prevent a real evaluation of a radio's capabilities....

So, how do you evaluate the quality of the reviews?  (maybe you don't, and "it all comes out in the wash" of the statistical analysis?)


To sum up....it's great that you did this, and I'm sure it helps some....just that part of me wishes it didn't continue to build on the myth that you can use "the list" to choose a rig.  :)

Fair winds and 73,

John,  KA4WJA

P.S.  Hopefully tonight or tomorrow, I'll have the time to finish my rig choice history / reasons, and my detailed thoughts....hoping this will shed some more light on things, from a personal (this is what I chose, and why) perspective, rather than just looking at one list?  :)
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #62 on: April 15, 2021, 02:27:56 PM »

Frank,
In case it didn't come through well in my post of earlier this afternoon, I do appreciate your hard work!!  :)
(although not my intent, when I reread my post, I realized that it might come off as critical...so, in case it does, I'm sorry....sometimes my ramblings just go on a bit too much...hi hi...)

Okay, gotta' go.

73,
John,  KA4WJA
Logged

K4FMH

  • Member
  • Posts: 681
Re: Choosing a rig and Sherwood's list
« Reply #63 on: May 09, 2021, 05:35:17 AM »

Frank,
In case it didn't come through well in my post of earlier this afternoon, I do appreciate your hard work!!  :)
(although not my intent, when I reread my post, I realized that it might come off as critical...so, in case it does, I'm sorry....sometimes my ramblings just go on a bit too much...hi hi...)

Okay, gotta' go.

73,
John,  KA4WJA

Hi John,

No worries. I think several of your Qs are because the statistical analysis was something one needs to digest a bit to appreciate exactly how those questions were actually addressed in the study.

Rob Sherwood was in contact with me during my analysis. He joined me on this talk to the Bury ARS recently and addresses a number of issues and questions that your post raised. You might get clarification through it here: https://youtu.be/mjquy-iVpW4.

Note that I explicitly state that my study is NOT to identify which exact rig to buy! Rather, it was to rule out many rigs that simply do not receive nearly as well as a smaller subset. And, if one does not think hams who post their satisfaction with a given rig on eHam is valid, why should we think their assessment is more valid? They are all valid to the individual poster.

Finally, money does not guarantee a high performing receiver that has been well-received by the amateur community. However, he may identify such a rig that may cost more than others. But, then, there are a number of others that meet the same objective criteria that cost a whole lot less! My study clearly identifies how much more we are indeed willing to pay for features and ergonomics. That’s not what a majority of hams who post about rigs appear to think and was the impetus for my study.
« Last Edit: May 09, 2021, 05:41:19 AM by K4FMH »
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #64 on: May 10, 2021, 10:42:35 PM »

Frank,
1)  Wow, I love it!  I just watched your video presentation, and I love it!

a)  Something that I didn't grasp from your earlier posting (that I now understand), is that you are not trying to find the "best" rig, nor are you advocating statistical analysis be used to find the "best" rig, and actually seem to imply / mention correctly that there might not be a "best" (which is good!)....and, are actually trying to see if prices "buys" performance and satisfaction.  Duh!?

b)  Also, I now understand the reasoning (statistician, I'm not!) of using all nine "specs" together into a composite index....maybe not my choice as a non-statistician, but I do understand it. :)   

c)  I also understand how you got the "price" data.

Although, this does also make me wonder if there is an "easy" way to look at the "price" based-on price of the radio when purchased by the reviewer (adjusted to current dollars), rather than the MSRP, when new?  (I understand this removes the manufacturers' "signal" from the discussion, but it might also give a better indication of "bang-for-the-buck", as many quality radios [particularly those no longer manufactured] are available at significantly less cost than their 2019-adjusted MSRP...perhaps you could incorporate this into your next analysis, when looking at transmit performance?)

Don't ya' just love it, when someone says "great job" and then asks for more?
  :)

d)  Oh, and now that I grasp how you used the stats of the eham reviews...(embarrassed that I didn't grasp that from your earlier posting....now you know why I dropped my stats-n-probability class!)...I'm now actually motivated to write some product reviews....especially of my beloved TR-7's!! 

So, thanks!! :)


2)  Frank, I find myself in a tough spot....'cuz I love what you've done....but I do have an issue with something....so, please take this as polite disagreement between fellow hams, nothing personal!  :)

a)  It's just that this isn't really a statistical analysis of "rig" performance, price and satisfaction....but rather that of "receiver" performance, transceiver price and satisfaction..

That is great!  And, I commend you on mentioning this in your presentation (along with your desire to look at transmit performance in the future)!

I'd just wish you'd have stressed that fact more, and maybe titled the presentation "Does Price Buy Receiver Performance or Satisfaction, in an HF Transceiver?"  That way everyone would understand the important subtlety of only comparing performance of half the transceiver.  :)

While I do understand the ease of using the word "rig" (I do this, myself), in this situation (when using only receiver test results) using the word "rig" can be problematic....and in my opinion, can be confusing (at best) to many new hams and/or those new to HF comms.

{Although every modern ham HF transceiver has a mic gain control, and most newer transceivers also have adjustable power-output (and a very few have transmit audio equalizer and/or transmit-width/passband adjustment....with the older/classic tube and hybrid transceivers having PA tuning/loading adjustments), the facts are that hams don't have much in the way of transmitter "adjustments" or "features"....and placing the mic gain control in an easily-accessible location is a no-brainer...So.}

So, when it comes to "features", "ergonomics", "adjustments" of our transceivers, it is clear that most of these are "receiver-based"...hence the conundrum.

So, if hams desire to see what is the "best" receiver for their application, that's cool!  Rob has given all of us a great table of data to look thru and evaluate.  And Frank, you've compiled a great deal of data and analysis, that is so wonderfully done, I can't believe anyone did it!!!  And, it is sure to help out a lot!

But, all of that is only taking into account half of the "rig", the receiver.....(oh, and yes...we all know that it's the antennas and operator skill that makes the most difference, but that's a whole 'nother topic)


b)  So, I'm still left with lingering thoughts....I love Rob and what he has done over the decades for ham radio, etc....and I love what he has done for my fav radios (R.L. Drake radios)....and for decades now I have read articles penned by him, and of course, I've watched his presentations, and I glance at his list to see what's been added/updated.

But, in your presentation and slides, you state that "The Sherwood Tables are generally the Holy Grail of rig evaluations from a workbench assessment"....here I disagree with you....as Rob's "tables" (aka the "list") are tabulations of receiver tests, not of the whole "rig".  Sure, they're a great resource and I do appreciate them, and use them to get a handle on modern receiver capabilities, but they are about the receivers.

I know some might think I'm being a jerk here, worrying about semantics and/or twisting things around to fit my argument / narrative....but, please understand I'm not....I am stating my long-held, (and long publicly-stated), opinion that looking at a "list" of receiver specs is nice, but it is not a way to choose a rig!  [although your statistical analysis is getting closer to being a good guide] And, in my opinion, using the phrase "rig" when only looking at receiver test results, will continue the myths and probably add to the confusion of new hams / hams new to HF comms. 

Of course, Rob does highlight some horrible transmit issues in some of his test reports (and I LOVE that!) as well as telling us all (for almost 20 years now), that in SSB operations it is NOT the receiver that is the limiting factor, but rather the transmit IMD / transmit spectral purity of all of our transmitters that is the limiting factor!  But, the list is about the receivers!


3)  Frank, in regards to your future analysis of transmitters....Wow, do I wish you luck!  (I think you may need it!)
a)  First off, we have many hams discussing receiver specs / test results and making choices of transceiver based only on test results of one half of the "rig"?  And, that's a big obstacle to overcome!   

b)  Then you have the issue that most of the "features and ergonomics" are receiver-based.


c)  The transmit spectral purity / transmit IMD data is out there for all....but you'll likely have some issues with it:

1-  You must look at (and use) all the IMD data, especially the higher-order IMD products, NOT just the oft-quoted 3rd order (which is usually in the SSB transmit passband, or just on the skirt).

As, it is the 5th and 7th order products that most often fall into the immediately adjacent stations QSO, and the 7th and 9th order products that fall a few khz farther up/down from your transmit passband.

Have a look at the typical human voice freqs (especially those of "loud" and "shouted", which would be typical in contests and dx-pileups) and you'll grasp which and where these will produce IMD products....and, you should be able to see why marketing folks quoting only IMD3 specs are touting rather moot points for SSB-Voice operations....



(and, please be aware that it's not just the design/tuning of the PA, and its drive/output levels, that effects its overall IMD levels, but in many cases, various products will fall into a null or rise on a peak, as the drive/output level is changed....meaning that one PA may have a great IMD3 spec and a poor IMD7 at a certain drive/output level, but a great IMD7 spec and a worse IMD3 spec, at a different drive/output level...which is a reason why, even I, am hesitant to make wide blanket statements based only on one set of test results...I usually back those up with on-air experiences.)

2-  You must also look at the ALC issues (not just initial overshoot), that can cause rather strong buckshot (MUCH higher than a static IMD product) up/down the band +/-15 - 20khz or more...many modern rigs have this issue (especially the modern Yaesu's)

3-  Some manufactures' transmitter designs/tuning/specs changed over the years (same model, different design/tuning/specs)....and, some radios weren't the "standard" 100-watt radios...

Case in point, the Drake TR-7 originally spec'd as 150-watt output (and ARRL testing done at that power), but shortly after debut was spec'd at "125 watt" output (with slightly different tuning), with improved IMD [note the maritime/commercial TR-77 and TR-4310, which met the older (more stringent) Part 80 cert, have the same PA as the TR-7, meeting the older (very stringent) Part 80 specs at 125 watts out]...making it better than any ham HF made in the past 45 years (excluding the FT-1000 MkV, etc. in Class A, and better than any ham HF rig made today, except for an ANAN with pre-distortion turned-on) (see my personal TR-7's scans, and that's a 43-yr-old rig that needs an alignment!)....and a still further slight redesign of the PA after the first year or so of production further improved its transmit IMD.

Some older/classic rigs, such as the Icom IC-781 (which used to be Rob's favorite rig) and the JRC JST-245, etc. were 150-watt radios....and the IC-775 and TS-480HX, were 200-watt radios, as were some of the Yaesu "MP's", etc...as well as an ANAN-8000, etc.

So, do you run them all at 100 watts to compare them with most other rigs?  Apples-to-apples?  Or do you just run 'em wide open, and let the poorer transmit IMD from the "marketing guys" prevail?  Or (my best advice) do you run them right where the factory says to?

4-  Do you take only the ARRL IMD test data (I suspect yes)?  Do you squint hard and look at the scans available to get the higher order products that weren't usually reported years ago?  Do you use "updated" data?  And, do you simply use the db(PEP) numbers for clarity/consistency, or do you use the db(c) numbers (and possibly confuse some folks)?

5-  Remember, in addition to ranting about this for a couple decades, a few years ago I put together pages of transmit IMD specs (from ARRL test results) for all to see....and, most of the responses are in the vein of "it's not a big problem", "it's only the guys who crank-up their mic gains, and/or over-drive their amps", etc...but, if they actually read the data and listen to the guys on-the-air...they might just see-the-light....(like the "buckshot" I hear from the new FTdx-101) [fyi, heard my first 101MP just this past week, splattering almost as bad as the 101d].

You may find these pages useful?

https://www.eham.net/community/smf/index.php/topic,97093.msg1053647.html#msg1053647

https://www.eham.net/forum/view?id=index.php/topic,97093.105.html%3f

https://www.eham.net/forum/view?id=index.php/topic,100600.0.html%3f

Sorry about the missing pics and spectral scans....I used tinypic as a hosting site and as you know, they no longer save archives....so, most of those are lost.... :(

BTW, I do practice what I preach....using a older/legacy rig (Drake TR-7) with clean transmitter and a nice Alpha amp....giving me a clean signal that doesn't pollute the airwaves....just makin' sure everyone knows I ain't talking outa' both sides of my mouth here... :) 

So, here is a recent (March 26, 2021) 2-tone IMD test of one of my TR-7's, showing 3rd/5th/7th/9th IMD products at  -43db(PEP) / -46db(PEP) / -50db(PEP) / -57.5 db(PEP)  [subtract 6db, for db(c)]  Not bad for a 43-year-old radio (that needs an alignment), huh?



[fyi, that's better than the wicked expensive (and 50vdc PA) TS-990s and IC-7800....and as much as 10db better than an IC-7300 or K3/K3S (and who wants products going on and on, like a K3?)....and 10 - 12db better than an IC-7600....and 12 - 21db better than a FT-991 or FT-857/897, etc.]


Oh, and here is a scan of a K3....(courtesy of Ron Sherwood)



Ask yourself who you would wish to operate 3 - 5khz away from?


As I have publicly said (and written) for many years (decades) now, in my opinion, it's the lack of resolve of hams (the customers) to demand better transmitters....and, unfortunately in the past decade, also in my opinion, it is the over-emphasis of receiver test results (and "the list"), which ignores fully one-half of the "rig" and hence gives credence to the myths that transmit IMD issues are "not a big problem" and "it's only the guys who crank-up their mic gains, and/or over-drive their amps"...when the sad fact is that there are currently new ham HF rigs on the market that splatter 10db to 20db worse than my old TR-7 (and 20-30db worse than a TS-830, or 32-S3), when operated exactly as the manual states!  And, unsuspecting hams buy them all the time (I suspect out of ignorance?).

Ironically, Rob Sherwood himself, has been stating his opinion on the failing of our transmitters now, for the same couple decades, and for 15 - 20 years, he has been stressing that for SSB operations it is our transmitters (NOT our receivers!) that are limiting our reception abilities!!! But, few hams seem to pay attention to what he says about transmitters?


Again, my opinion here, but I suspect part of the reason is that way too many hams look at "the list" of receiver test results and think this is the "whole rig", forgetting the other half (the transmitter!)?  The other part of the reason is that many hams (especially those new to HF-SSB comms) have no clue what transmit IMD / spectral purity is?  {and, of course, also what I've written many times....most hams never listen to what they sound like on-the-air, especially off-freq a few khz....most never listen to their own transmit spectrum / IMD....a shame, in my opinion, 'cuz once you show someone what they are transmitting versus what someone else is transmitting, it becomes clear to most...}


d)  Of course, in addition to the transmit IMD / Spectral purity, there are many other transmit specs:
The RF power output....power output and transmitter duty-cycle in all modes....power output adjustment range and the ability to maintain whatever output you desire (so you don't over-drive an amp, and/or overload other devices)....again, ALC issues....transmit composite noise (that Rob has been successful in getting some manufacturers to improve)....transmitter VSWR operating range / "SWR foldback".....transmit audio passband....speech processing/compression....audio distortion....RF shielding....CW keying rise time / CW bandwidth....digital-mode/soundcard-mode passband linearity and flatness....DC (or AC) power requirements....transmitter efficiency...PA cooling....PA-disable (for transverter operations)....LF and VLF operations....harmonic and spurious output....XIT....etc. etc...

You see there are just as many "specs" regarding the other half of our "rigs" (the transmitter side)... :)



Fair winds...and 73,

John

P.S.  I've been caring for my Mom quite a bit this past month (she had a bit of out-patient surgery), but I will try to finish my "personal rig choice" story (including some transmitter scans)
« Last Edit: May 10, 2021, 11:02:59 PM by KA4WJA »
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #65 on: May 13, 2021, 08:22:40 AM »

David, Brian, Frank, et al,
1)  As I've said for years (actually decades now), transmit cleanliness is my personal #1 criteria of rig choice...a clean transmitter, with low IMD products (especially having the higher-order products that fall off), is what I use to weed out the rigs that might be "good enough"....but, I'm NOT going to ramble on about IMD here in this thread..

This thread is about Rig Choice and Rob Sherwood's List....and, I'd like to take a slightly side-ways look at “How to choose a rig” {hint: The short answer to that question is:  Unless you’re a serious big-gun CW contester, the list is not the best way to choose a radio!  And, if you’re not a serious CW op, it’s the transmitter IMD that is so much more important! The long answer is: everything I posted here in this thread. :)}

And, while ergonomics is of course important, it’s pretty easy for a manufacturer to "get right"?  I mean, if a manufacturer gets the basic layout wrong, or has ridiculous menu steps, etc., just pass it by and look elsewhere, 'cuz there's no telling what else they just didn't care enough about!

The most used knobs are:
a)  VFO;
b)  RF Gain;
c)  Volume / AF Gain;


These make up 95% of the daily / continuous use.
After that, you have Carrier / power output, attenuator, RIT, the band-switch, filter selection, pass-band tuning / IF-shift, and noise blanker / noise reduction, AGC...the order of priority of these controls varies with the user/operator and their type of operating / bands / antennas / etc...but, all are secondary to the "big three" above.

Things like VOX Gain, crystal cal (how many even know what it's used for, let alone still have one in their rig?), fwd/ref power, swr, etc., these are usually a set-n-forget, or once-in-a-while use.

So...if you make the VFO, RF Gain and Volume/AF Gain, controls (and possibly the rec bandwidth/filter selection control) easy-peasy and in comfortable position to use, the ergonomics are pretty easy to get correct.....rigs that don't get this right, are probably not designed by hams / not designed by radio ops....further, if you put the attenuator, band-switch, RIT, and now-a-days the power output control, in good location on the front panel, and/or place most of the other often used controls in a logical location, you're good-to-go.

If not....just look for another rig.


2)  And, if you choose a radio that sounds good / not noisy or distorted audio (as the K3 has), you're also good....Where the radio sits on a "list" is mostly irrelevant!  So, how about a personal / historic look at "rig choice"? 


3)  In all seriousness, maybe a discussion of "rig choice" from a personal / historical point-of-view might be helpful to many folks here?  You know the "I chose this, because of ____, and I've found it to be great (or useless)"

Notwithstanding Brian's fondness for the old "hot water one-oh-one", I was never a fan, but did like the Heath SB-series....although, in the early 70's it was the Drake "twins" that I drooled-over (R4B/T4XB and then the "C-line"....oh how I wanted Drake "twins")....but.

But, seriously I'd like to paint an honest picture of my own personal choices over the past ~ 50 years, showing my early ignorance as well as some happenstance that steered me to superb results....(there will be some embarrassment here, so before you criticize my ideas from my youth, or brag about how great your new radio is, I ask you all to think back decades to first see if you've ever been ignorant of something once, and then later learned the facts?)

So, here goes.


4)  As I said in the early 1970's, I was reading (mostly advertisements at first) about different radios, and was dreaming of the Drake R4B and T4XB Twins...just loved their look (and oh the copper-plated chassis, I just "knew" that made them work so much better?).....now this was 1972 or so, and I was 11 years old, and fairly ignorant....all I had was a SW receiver, and scrounged a sig gen (and a couple CB radios).....I used the sig gen as a BFO to listen to some 40m and 75m ham SSB signals....(I also started to talk to some local guys on 11meters, but soon tired of that)


5)  Living in Ft. Lauderdale (and sailing the islands) there was a lot of HF maritime comms going on, so I started in HF on the maritime bands and using commercial, crystal-controlled, maritime rigs.....assisted in my first HF maritime installation in 1973....learned how to use a Bird 43, and adjusting a remote antenna coupler/tuner, using both the Bird and a fluorescent light bulb! 
(these remote antenna couplers/tuners were not "automatic tuners", but rather stepper-motor driven switched, with tapped coil and two air-variable caps, for each position/channel....and each position needed to be tuned/adjusted for max antenna current / minimum SWR) 
The guys at the marine electronics shops loved the "Sailor brand" marine rigs, and Collins ham rigs....and I learned about "clean transmitters" from them, as they were required to maintain spectral purity!

I joined the ARRL in March of 1974, bought my first "Handbook". etc....and reading QST every month, I saw all the ads for all the radios, and was still drawn to the Drake "Twins".

Little did I know that the wide crystal filters and LC filtering (3.4:1 shape factor!) in the R4B might give you a nice sounding receiver, but just didn't have the skirts needed for crowded Phone bands...(again, this was the early 1970's, and I was only 12 to 13 years old.)  And, while the Collins gear had "455khz mechanical filters", which sounded great to me....I was unsure what "mechanical filters" were, and ignorant of the short comings of this design as well, especially in crowded bands, etc.

{it took me a couple of years of on / off studying, to get a decent understanding of HF receiver design and important criteria to look at.....thanks to the Handbook, some QST articles, some reading at the library, and of course articles and papers from Doug DeMaw and Ulrich Rohde!}

Around this time, 1973 up thru 1975/76, I was exposed to the Collins KWS-1 / 75A-4 at our local community college, and was taught how to tune and operate them.....it was cool, but I think I just loved the experience of learning about these radios / learning how-to tune them / use them, more than the radios themselves!  :(  And, my friend (an EE student) and his professor both commented on my dreams of the Drake "twins", saying "they're just a 'poor man's' Collins"....but, that didn't deter me...They also stressed the adage that "separate trans and receivers was THE only real way to go"....'cuz it allowed you to run the transmitter hotter, and not have it effect the receiver, drift, etc...saying that "no serious ham uses a 'transceiver'" (of course, this was contrary to the experience on maritime comms, and contrary to advice from the maritime installers...but, maritime was all crystal-bound, no VFO's, so I assumed these hams / professors must know what they were talking about? 
Again, it took a couple years to figure out how full-of-crap they were, my first experience with PhD's, little did I know how prolific this early exposure to academia would be...some are great, but some think the “p” and “h” should be a “g” and “o”.)   Also, when I asked them about a "clean" transmitter, they said something about needing to use a "spec analyzer" (which I had no clue about, heck I was only like 12 or 13 years old!) to see, but they said that wasn't possible to do now {years later, I found out the old KWS-1 wasn't that great in that area....I think it had a pair of 4cx250b's and not designed to be "super clean".....compared to some maritime rigs, using 6146's (some using three of them, for 150 watts PEP) and/or the big ones using a 4cx1500b, that old Collins wasn't very good in comparison. :( }

Concurrently, I had a friend in the TV repair business who just bought a Kenwood TS-520....and while it was a nice radio, when at his house operating it, I found myself thinking that both the marine HF radios I'm using and the old Collins at the community college, both sounded better and some friends with other ham radios on 11 meters made contacts more easily.....of course, it was about this time that I was learning more about antennas, angles of radiation, radiowave propagation, etc. (learning that the ionosphere controls the angle that our signals are reflected at, not our antennas.....and also learned that many hams didn't know that!)

Also, around this time I had some friends with FT-101's (and Tempo One's) on 11 meters....and, quite frankly I found the FT-101b to be much better radio than the TS-520, the Tempo One, and even better than the Collins (?) and was easy-to-use/tune/etc.
Further, about this time, Drake had come out with the new "C-line" (R4C/T4XC) and I still had hopes of someday getting something like that.

And, I was reading more and more about HF receivers, radiowave propagation, and antenna system design....somewhere in there, I remember a great article, where I learned a lot more about HF receiver design than I actually knew I learned (this was my first exposure to receiver dynamic range, etc.), and this is when I started to become critical in my dreams / choices of radios...somewhere about this time as well, Rob Sherwood was writing about receiver IMD and Drake R4C improvements, but I didn't read these articles until years later (think I was in college in the early 80's when I first read Rob's articles dealing with this?)

But, about this time girls and cars were distracting me....girls especially.....but, depending on my mood, and theirs, sometimes "cars" were easier to deal with.... :)  [ya' know, surprisingly, ~ 45 years later, cars sometimes are still easier to deal with!] So, while I still had dreams of the Drake "twins", that was on hold, for the moment.

Fast-forward a couple years, and my radio dreams had matured quite a bit..
I wanted a "clean" transmitter that could be used on the maritime bands, and wanted a 12vdc-powered radio (fyi, my Dad's old Raytheon marine radio had a "Dyna-motor" Hi-Voltage power supply, but his newer HF marine radio was solid-state!), and of course I also desired a "transceiver" (oh, the horror...LOL)

Using those criteria in the mid to late 1970's the choice were limited....in 1977/1978, the Drake TR-7 was the only one that fit the bill, but the Atlas 210x/215x was a secondary choice for "12vdc ham transceiver"....and, the Icom IC-701 was being advertised and soon to be released, and might also be a decent 12vdc ham rig, but neither the Atlas or the 701 would work the maritime bands, and I had no clue how clean their transmitters were?

So, the choice was a Drake TR-7...

As I looked closely at the TR-7, in addition to it passing muster in the "clean transmitter" category (not surprising...as the TR-7, the Drake TR-77, maritime version and the Drake TR-4310 commercial, land-mobile, maritime version...all use the same transmit PA, etc.);  it also had a clean and well-thought-out transmit path, from a clean mic amp and balanced mixer, to the RF tightness of the entire transmit stream; 

Then I also saw that the Drake TR-7 incorporated many of the receiver design criteria that had been detailed earlier in those articles / papers....hi-level DBM receiver front-end (no RF amp in the receiver);  extremely high blocking dynamic range (next to impossible to overload);  distributed receiver gain and selectivity, using wide skirt First IF filtering to allow excellent noise-blanker performance as well as not induce ringing nor adverse group-delay distortions in the receiver IF chain;  quiet, low-distortion, receiver, that is comfortable to use for many hours straight;  continuous tx/rx coverage 1.5mhz - 30mhz (what we refer-to as an "up-conversion" radio);  effective noise blanker, which was a $90 option back then (that's $375 to $400 in today's dollars, just for the internal noise blanker), which to this day in 2021 is still one of the best/most effective noise blankers ever put in an HF radio, along with the attention to detail in the receiver (high-level DBM input, wide-skirted First IF filer, distributed gain and selectivity, etc.), it actually works great and doesn't materially effect receiver performance;  after initial 10min warm-up, doesn't drift;  "tight" second IF filtering, allowing excellent SSB/CW operations;  overall RF tight and well isolated internal systems, allowing for high total ("ultimate") selectivity, no filter "blow-by", and on and on.

I researched / learned all of this before I got the radio....(my Dad offered to match me dollar-for-dollar for my first new ham radio, if I'd give up chasing girls and building hot engines....I said yes, but you know I was a teenager, so that didn't really last.....took me another year to get around to passing the tests....but, I was having fun, you know...)

So, ~ 43 years ago, I got a Drake TR-7, w/NB-7, RV-7, etc...and using some homebrew antennas, etc., set about understanding how great the radio really was!   (and still is!)    Also, used it aboard, and occasionally on the 22mhz maritime band...

As I wrote earlier, the TR-7's transmit IMD is very good (by today's standard) and it's receiver performance is excellent, even by today's standards....sure the VCO's are noisy in comparison to the best available today, so in narrow-spaced rec IMD testing (how Rob's list is organized) it is "noise-limited" at 76db (at 2khz).....but is 99db at wide-spacing! 

And, until the IC-7851, the K3S, the TS-890s, and FTdx-101d came along, the Drake TR-7 had the highest Blocking Dynamic Range of any radio on Rob's list (darn near impossible to overload)...and even now these four wicked-expensive rigs only beat the TR-7's BDR by a couple db...

Think about that, one radio (the Drake TR-7) held the top spot in Blocking Dynamic Range, for 40 years!
And, in narrow-spaced 3rd order rec IMD, it beat the Elecraft K2, and right next to the IC-756ProII and ProIII, and the TS-590s (in "up-convert" bands) ....and, the "modern" second-gen 21st Century rigs like the IC-7600 and IC-7700 only beat the TR-7's narrow-spaced rec IMD spec by a few db (within production errors), and they're "noise-limited" as well....so, "modern" radios that are 30 - 35 years newer design are about the same in the spec that "the list" is arranged in (narrow-spaced 3rd order rec IMD), compared to a 1970's era Drake TR-7!! 
(Sorta' makes you smile at how good that TR-7 is / was, huh?  And, we've not even looked at how good the transmitter is, yet!)

Then a couple years later, at university we first had a Kenwood TS-820s, then a TS-830s....and a big homebrew 4-1000 amp, long-boom monobanders for 40m - 10m, on 3 tall towers on top of 2 six-story buildings (on top of one of highest hills for miles around) fed with hardline, full-size 80m dipole at ~ 140' above ground (at the top of that hill) fed with a couple hundred feet of "FM-8"...as well as a TS-700, ext pre-amp, and stacked long-boom yagi's for 2m SSB/CW.

I found the TS-830s to be a nice rig (still my favorite Kenwood!), but if you cranked-up the noise-blanker (it was adjustable) high enough to actually work, it caused serious issues in the receiver....but other than that, having filters in both IF's (8.83mhz and 455khz) and using the VBT (and IF shift) meant you could operate in very crowded bands, even with big antennas, etc....and its transmitter (with 6146b's) was wicked-clean....and good sounding audio (transmit and receive). 
Still had the TR-7 (~ thousands of miles away, so I couldn't do a side-by-side comparison), but, after lots of operating I found the '830 to be very nice (better than most), but still not quite as good of receiver as the TR-7!  And, of course the TR-7 runs on 12vdc, and works tx/rx from 1.5-30mhz.
That was all ~ 40 years ago!!!


6)  Now....with SSB operations being constrained by the other transmitters on the air (their transmit IMD), not by the specs of our receivers (even those with mid-70db narrow-spaced rec IMD), and since I'm not into serious CW contesting, I've not changed out the VCO's to something modern with low-phase noise (which Ulrich Rohde wrote about)....
Fyi, even with what now-a-days is considered mediocre narrow-spaced rec IMD we used my TR-7 in a very successful result, in the CQWW 160m CW contest in 1990, running barefoot ('cuz our amp burnt up in the first hour of the contest), so you actually can use an older receiver that's "way down the list" for CW operations, AND actually be competitive in a cw contest... :)

Who knew that hams actually could make contacts before "100db radios" were on the market? :)
Next thing 'ya know, someone will be saying that some hams, my Mom's age, used "spark" transmitters to make contacts?  Oh, the horror...  :)


7)  Now, about 25 years ago (late 1990's), I wanted a second HF rig....spent some time looking / researching, and found nothing even came close to the TR-7....so.

So, I found another clean TR-7 (this was before everyone thought they must be made of Gold?)....cleaned it up a bit, and viola I had a nice modern, excellent "second HF rig"!

BTW, I also own three Icom M-802 MF/HF Maritime Radios, two on-board my boat, and one at home….these are 2004/2006 era-design (similar in time-frame to the 756ProII/III)…but these have a totally different PA that is150 watt output (100% duty-cycle FSK rated), and this rig is FCC Part 80, Part 87, and Part 90 certified MF/HF-DSC-SSB-CW-FSK marine radio, that have easy-peasy “one-button” ham/vfo mode, and while tune in 100hz steps, they make excellent HF ham rigs on-board….(but are really niche radios, so I won’t detail them here)

Please see my next posting, that is a continuation of this one.


Fair winds and 73,

John,  KA4WJA
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #66 on: May 13, 2021, 09:19:22 AM »

    ~~~~~~~~~~~  Continuation of above posting  ~~~~~~~~~~~

8 )  Except for adding a 1.0khz wide (narrow) IF filter, and making a couple minor feature modifications (configured the front panel “Carrier” control, to control max power in SSB mode as well as CW/AM, repurposed a front panel button for PA disable for easy-peasy transverter operation, etc.), my TR-7's are factory stock!

And, except for replacing S-meter light bulbs, and cleaning some internal contacts (one of my TR-7's spent time on-board an ocean-going sailboat, you know...), I've never needed to repair them! 
Yep, you read that right....they've never needed repair, at 43 years old, and they still hold their own against "modern" rigs! 
{I did send my original TR-7 back to Drake (in the late 80's / early 90's?) for a few updates (they added an input protection and couple other minor changes, to make it a TR-7A) and an alignment, but no actual repair of either, and they still work great at ~ 43 - 44 years old....and I do use 'em, they're not "collector's items" up on a top shelf!}
BUT..

But, I do need to do a re-alignment.... :(  component aging and some internal adjustments are a bit "sensitive".

I get many unsolicited reports of "great audio" and "really clean signal".....and, hanging out with a few guys on 75m that run Apache ANAN's with pre-distortion, they commented that I have the cleanest "non-ANAN" signal they've seen!  So, while I do need to do an alignment, and bring things back to new spec, my TR-7's are damn sweet!  :)


9)  About seven years ago (2013 / 2014), I started to think I might want a new HF rig (“just because”).....so, I started looking/researching again....and found (except for the classic MkV in Class A, or the pre-distortion equipped Apache ANAN's) none had a transmitter as clean as my TR-7....and I'm not interested in running a computer just to talk on the radio, so I just gave up...but, if I could find a reasonably-priced MkV, I still might just go for it...Class A, ya' know...
(but the Kenwood TS-590SG did look okay, and this past year someone recommended the TS-890S....and now, in 2021, Apache is debuting their "Andromeda", which is their "SDR with knobs", and that might be a contender, we’ll see?)

Of course, Rob doesn't even list transmit IMD…but, it is important to everyone on-the-air these days.  (yes, some over-driving their amps, and/or running their mic gain too high, do contribute to the problem, but fact is many modern ham rigs are just crap in transmit spectral purity, and that’s when they are operated “properly”!)

And, coming back to this thread's actual subject (rig choice and Rob's list) as I look at the new progression on Rob's list, I see that full SDR / direct-sampling rigs are being topped by modern "hybrids" (FTdx-101d) which are what we used-to call "IF-DSP rigs"! 
It's just now these “IF-DSP rigs” have very-low-noise synthesizers, and are more traditional "down-convert" IF rigs (which have low HF first IF's, not VHF first IF's, and hence can have narrow first IF filters, what is now called a narrow "roofing filter"), rather than the IC-756ProII/III's, etc., that had wide VHF first IF's and noisy synth...
And, while I suspect DSP noise blanking / noise reduction is improving, having the noise / noise pulses reshaped and delayed by a narrow first IF filter, will make this difficult to be truly effective?

So, that's where I'm at...
That's my history and choices....~ 45 - 50 some years of HF rig use / choice....the reasons and results.
And, I’m still running ~ 43 - 44 year old HF rigs!  ‘Cuz I just can’t find ones that are “better”, unless I could spend $5k - $10k (definitely not going to happen), and/or want to operate a computer just to talk on the radio (not likely, here)


10)  Finally, while I wrote up top that I wouldn't ramble on about Transmit IMD here, since that is my personal #1 criteria for "rig choice", maybe I should post some 2-tone test scans, and a few sentences about why/how this has become such an issue?

In addition to my recent (March 2021) scans of my 43-44 year old (and in need of alignment) Drake TR-7, I will include five scans for comparison here (and one clarifying white-noise vs. 2-tone testing, using an IC-781), courtesy of NC0B, Rob Sherwood, himself....saved from a couple of his presentations in the past 10 years or so:
a)   a Collins 32S-3 (at ~ 100 watts PEP); 
b)   a Yaesu FT-1000 MkV, in Class A (w/o any ALC action) at ~ 75 watts PEP; 
c)   an Elecraft K3 (at 75 watts PEP);
d)   one “double scan”, showing a “classic” IC-756ProII versus a “modern” IC-7600;
e)   another “double scan”, showing a FTdx-5000 in Class A comparing it with NO ALC, versus ½-scale ALC;
f)   2-tone vs. White Noise, using an IC-781; 


Fyi, my TR-7 has about the same IMD responses from 5-10watts PEP, up to 125-130watts PEP....some products are lower a db or so, and some are higher by a db, throughout this whole range of power output....although at 150-160 watts PEP out, IMD goes up 2db from the figure at 125-130 watts.  And, since I drive an Alpha 78 (or an Alpha 77Sx) with my TR-7's, I have the TR-7’s set to have a max output of ~ 60 - 65 watts across the whole HF spectrum....and, since I also wanted to test the final IMD (of the combined TR-7 and Alpha 78) at 1500 - 1600 watts out, I decided to do the TR-7 tests at my normal drive level of about 60 watts (~ +48dbm)...I have a Coaxial Dynamics tap connected on the side of my Bird 43, set at -68db (at 3.65mhz), so max output into my analyzer from the TR-7 is ~ -20dbm... (and ~ -6dbm from the Alpha 78). {BTW, also since the K3 was being operated at its "sweet spot" of 75 watts, as well as the MkV in Class A at 75 watts...I figured this would be acceptable to show as comparisons....but fyi, this is not a scientific transmitter comparison treatise, rather just a way of showing examples of what is out there, what is clean, and what isn't. :)}

Fyi (especially for those who question the use/validity of two-tone-tests), look at human voice freqs, where normal or raised male voice freqs peak in the 400hz – 600hz range, and roll off below 200hz and above 1600hz, falling off steeply above 2000hz.  And, “loud” male speech peaking about 650hz, but rolling off at the same rate and freqs. (female voices a few hundred hz higher)
So, using two (non-harmonically-related) tones, one low (600hz-800hz) / one high (1600hz – 2000hz), does actually approximate the mixing of various human voice freq, so while a “two-tone-test” isn’t perfect, it’s actually pretty good (see comparison of a two-tone vs. white noise scan of a Icom IC-781, courtesy of Rob Sherwood) and, you all do realize that it wasn't hams, nor ARRL, etc. that came up with these tests / freqs....it was old Ma Bell, RCA, Motorola, etc., etc., etc...way back decades before I was born. :)
[Of course, a static 2-tone-test typically does not show the “buck-shot”/IMD caused by poor ALC systems, nor power supply issues, etc. but, it is the “standard” that we have.]






For marketing purposes (or maybe we should just say “for BS purposes”?), many brochures and adverts will spec an IMD3 number, but as you can see, with our normal speech freqs, typically the IMD3 product of our SSB transmitters falls either within our transmit passband, or darn close to it, on the passband skirt….so, it’s the 5th and 7th order products that are most responsible for adjacent-channel splatter, and the 7th, 9th and higher that are what presents as splatter beyond the immediately adjacent freq, 5khz to 10khz (or more!) up/down the band….but, many times a lot of hams don’t look at the higher order products.

So, to give a way to compare different rigs, just look at the width of the SSB signal at -60db from PEP, or even lower. (This is what is typically used in occupied bandwidth comparisons of various ham rigs, and by many giving seminars, such as Rob Sherwood, NC0B, etc...and as we see the 2-tone IMD products follow the curve of a white noise test pretty darn closely, so for our comparison purposes, we can make darn good comparisons!)

If you look at these scans, you'll see how nice and narrow that classic FT-1000 MkV in Class A is!  (and, as long as you do not have any ALC action, it really is that wonderful....even better than pre-distortion-enabled ANAN's, or an old Collins 32S-3, unfortunately you don’t hear many using Class A on these, as Yaesu didn’t design adequate cooling for this and some have called the MkV in Class A a “blast furnace”)....and you'll see the vintage tube Collins 32S-3, is super clean and its wideband / higher-order-products are wicked low....and you can see my old TR-7 (although needing an alignment) still makes a nice clean signal....but, opppss, you'll also see that K3 is wicked-wide and a rather poor choice for SSB operations (btw, the newer K3S is even a few db worse!)...

Now, to be clear, I’m not picking on the Elecraft, the Icom IC-7700 is just as bad! [It’s just that these rigs (Elecraft and the FTdx-101's, etc.) are not only commonly talked about as the “Holy Grail”, but are also the ones that Rob Sherwood uses as comparisons in his presentations, in regards to transmit IMD, and ALC issues...] 
BTW, the IC-7600 isn’t too much better…and, if you’ve got any ALC indication (especially on any Yaesu radio), you’re probably pretty wide…and anyone running a rig in Class A, should not have any ALC at all, or they might as well give up on Class A operation, ‘cuz all it’s doing is heating your shack (but, if you set it up right, with NO ALC at all, you’re going to have the cleanest signal on the band!)

So, if you’re thinking of spending $1000’s of dollars for a new rig, you may wish to actually have a look to see how that rig might be polluting the air-waves, causing you and everyone else, troubles….and ironically, it’s these crappy transmitters that prevent most of us operating Phone (SSB) from even coming close to actually using the potential of the receivers in these rigs….
Sorta’ like we are all throwing money down the drain, buying radios with great receivers that we cannot use the potential of, because of the crappy transmitters inside, huh?


SSB transmit width, at -60db below PEP:

FT-1000 MkV (in Class A) : ~ 3.2khz wide at – 60db PEP (and ~ 3.5khz wide at -60dbc), with IMD3 of -42dbc, and IMD5 at -70dbc (that’s IMD3 of -48dbPEP and IMD5 of -76dbPEP), and only 6khz wide at -80dbc – 86dbPEP…remember that’s in Class A, without any ALC action at all!



FTdx-5000 in Class A : ~5.5khz wide at – 60db PEP with NO ALC, and ~11khz wide at – 60db PEP with ALC at ½-scale.



32S-3 : ~ 11khz wide at -60db PEP  (and ~13khz wide at -60dbc), with IMD(pep) numbers of -42 / -53 / -65 / -76



TR-7 : ~ 5.7khz wide at – 60db PEP  (and ~ 13khz wide at -60dbc) with IMD(pep) numbers of -43 / -46 / -50 / -58



IC-756ProII : ~ 11.5khz wide at – 60db PEP versus the IC-7600: ~ 16khz wide at – 60db PEP



K3 : ~ 20khz wide at -60db PEP  (and ~ 29khz wide at -60dbc), with IMD(pep) numbers of -33 / -40 / -48 / -50
 


Yes, I see the asymmetrical response in the scans of my old TR-7 (needs alignment)....but, if you actually look at the numbers and examine the transmitter width at down -60db(PEP) and down -60dbc (-66dbPEP), and compare that width to that of the old Collins 32S-3 (w/ 6146b's in the PA), and that of the "modern" Elecraft K3, the IC-7600, the classic IC-756ProII, the FTdx-5000 in various configurations of Class A, and even that of the "classic" FT-1000 MkV in Class A...I think you might be enlightened? 

You can see how the 6146B PA, and the Class A SSPA’s (with NO ALC) have much lower wide-band / higher-order products…and how the crappy ALC of Yaesu (and others) seriously impact transmit IMD….and, in general, how crappy our transmitters have gotten….now, as I’ve said for years, with radios marketed with dozens of controls for the receiver and only two (power output, and mic gain) for transmit, and with few hams actually listening to their own signal OFF FREQUNECY, no manufacturer cares how crappy their transmitters are….so, it is up to us, to care….and up to us to voice that concern with our wallets!

What if NOBODY bought a new HF rig this year, that didn’t have excellent (or at least improved) transmit IMD…fyi, that would mean the ONLY HF ham rigs sold were ANAN’s….what would Icom, Kenwood, Yaesu, Flex, and Elecraft do?  Maybe they’d get the message?

Hmmm….Maybe this is an idea worth thinking about??


Ask yourself, who do you wish to operate a few Khz from?  Or even 5 - 10khz from? 
I know I'd rather it was a guy with a 32S-3, a TR-7, or a MkV in Class A, or an ANAN!

But, maybe some enjoy listening to splatter? 
We know the managers and executives at the radio manufacturers must love listening to splatter at home, ‘cuz that’s the radios they’re making / selling now-a-days, but what about the rest of you? 
Do you all enjoy the splatter? 
If not, how about stop buying new ham gear? 
What if a few hundred thousand hams wrote letters (not emails, but real letters on paper) to Icom, Kenwood, Yaesu, Flex, and Elecraft, saying “I was going to spend $2000 (or $3000, or $4000, etc.) this year or next, on a new HF radio, but since you don’t make a radio with decent transmit spectral purity, I’m buying an older rig, or a commercial marine radio, or a rig that has a Class A PA, or an ANAN w/ pre-distortion, etc.” 
Hmmm, what would they do, if NOBODY bought any more radios with crappy transmitters? 
I suspect we’d have better PA’s in 6 months, radios with Class A PA’s in a year, and mass-produced rigs w/ pre-distortion in less than 2 years?
Maybe not, but I think it’s worth a try….what do you all think?

If you all think, it’s worth a shot, I’ll be the first to write my letters….let me know… 😊


11)  So, to sum up….some might actually see how to use Sherwood’s List in choosing a rig? 
And, certainly Frank has showed us that many hams are satisfied with their choices, especially those rigs that score high on his SPI (Sherwood Performance Index)…but, as I have been saying for many years “few hams actually listen to/monitor their signal…and fewer still understand what their signal is doing 3-6khz (or 10khz) away”, so they might actually be “satisfied” with their rig, ‘cuz they don’t actually know what they are transmitting (and that is a sad fact).

In my opinion / in my experience, the short answer to that question is:  Unless you’re a serious CW contester (especially a “big-gun”), the list is not the best way to choose a radio!  And, please remember even serious CW contesters need a clean transmit signal (albeit IMD doesn’t play a role in a CW transmitter, rather it is CW keying rise-time/waveform, as well as transmit composite noise), so once they find some rigs with great narrow-spaced rec IMD, they should next be looking at its transmitter purity!!

Now, since most of us are not serious big-gun CW contester’s, “the list” isn’t nearly as important to the “average ham’s” rig choice, as some might think…I’m not arguing Frank’s statistical analysis (where some rigs that perform well on Rob’s list, do have high satisfaction scores), but merely stating a fact, that “the list” only shows specs/performance of half the radio…and reminding my fellow hams that the transmitter is the very important other half of the rig!!  And, for SSB Voice (and digital modes that require linear operations), it is the crap from our transmitters (IMD / Splatter / non-linearities) that is the limiting factor in our receivers! (hence, why I keep saying that the transmitter is such an important part of our shacks…certainly more so than most folks think!)

The long answer is:  everything I posted in this thread!  😊


That's my history and choices, over ~ 45 - 50 some years, of HF rig use / choice…the reasons and results....and I hope some find this helpful?

Fair winds and 73,

John,  KA4WJA

P.S.  I'm sure some will counter this with an argument regarding the "need" for a 60db S/N or S/I ratio on HF ham bands.....maybe saying this isn't like commercial users, etc....and sure that's all true...but how poor of S/N ratio do you desire to communicate with? 
Anyone who has sat and listened to stations only 10 - 20db above the noise, or during summertime T-Storms here in Florida, when those static crashes can be S-9+30, knows that 30db S/N is good, 40db S/N is better....so maybe pick a number like 40db or 50db, and see what rig you can operate next to...and remember that this is all assuming the guy next to you is giving you the same signal strength as the guys on your freq...
Oh, and yes....I get it....some will also say that we hams move in too close to each other on the bands....and, if it's a weekday evening, no worries about moving apart....but on a cool winter's Saturday night?  Or a contest weekend?  Well, you're lucky if you find a spot 3khz wide!  :)
{fyi, you're still gonna' want to be > 4khz above/below anyone with a K3, and that's if they're running barefoot at the sweet spot of 75 watts....and, oh baby, stay well away (6-10khz) from guys running FT-857/897''s FT-991's, etc.}
« Last Edit: May 13, 2021, 09:35:28 AM by KA4WJA »
Logged

KA4WJA

  • Posts: 1601
    • HomeURL
Re: Choosing a rig and Sherwood's list
« Reply #67 on: May 14, 2021, 07:31:16 AM »

Hello to all,
After talking to some friends on 75m last night, I realized that a brief clarification might be good...

Please note that the "occupied bandwidth spec at -60db down" is just that, a "specification", something used as comparison, etc., not necessarily a goal to achieve for "adjacent channel response".
(Similarly to how an IF filter may have its response specified as a "passband of x.xkhz at -6db, and y.ykhz at -60db")

While I might hope for a 60db S/N on all HF contacts, that's a pipe dream!  And, I hope I didn't imply otherwise!  :)

I mentioned this in passing in my post-script, but thought a bit more clarity might be good?
   P.S.  I'm sure some will counter this with an argument regarding the "need" for a 60db S/N or S/I ratio on HF ham bands.....maybe saying this isn't like commercial users, etc....and sure that's all true...but how poor of S/N ratio do you desire to communicate with? 
Anyone who has sat and listened to stations only 10 - 20db above the noise, or during summertime T-Storms here in Florida, when those static crashes can be S-9+30 [S-9 +20], knows that 30db S/N is good, 40db S/N is better....so maybe pick a number like 40db or 50db, and see what rig you can operate next to...and remember that this is all assuming the guy next to you is giving you the same signal strength as the guys on your freq...[If your friends, that you're in QSO with are S-7 to S-8, (as are the guys adjacent to you, and their IMD products are -40db down in your passband), and someone jumps in 3khz on the other side of you who is S-9+10db, remember that your "40db" S/N ratio, just became 15 to 20db!  :(

Oh, and yes....I get it....some will also say that we hams move in too close to each other on the bands....and, if it's a weekday evening, no worries about moving apart....but on a cool winter's Saturday night?  Or a contest weekend?  Well, you're lucky if you find a spot 3khz wide!  :)

I just thought I'd clarify my position, so that we're all on the same page.


73,
John,  KA4WJA
Logged

W9IQ

  • Member
  • Posts: 8866
Re: Choosing a rig and Sherwood's list
« Reply #68 on: May 14, 2021, 09:16:48 AM »

My usual friendly reminder that the unit abbreviation is written dB, not db. Many people are trying to learn from this site - let's teach it correctly.

- Glenn W9IQ
Logged
- Glenn W9IQ

God runs electromagnetics on Monday, Wednesday and Friday by the wave theory and the devil runs it on Tuesday, Thursday and Saturday by the Quantum theory.

K1FBI

  • Member
  • Posts: 1475
Re: Choosing a rig and Sherwood's list
« Reply #69 on: May 15, 2021, 03:56:15 AM »

He could be cited for the kilohertz abbreviation also.
Logged

VE3WGO

  • Member
  • Posts: 666
Re: Choosing a rig and Sherwood's list
« Reply #70 on: May 15, 2021, 08:12:19 AM »

Rob Sherwood's list can be useful to show us which receivers have serious flaws.  And most of those are older models.  Other than that, most of the newest ones have great receivers.

Sometimes I haul out one of my vintage receivers for nostalgia's sake, and put up with the coffee-grinder background noise on 80 and 40 meters.  Without a good Noise Reduction function and a good Noise Blanker, it can get very fatiguing to listen for a long time.  Good IMD and Blocking specs can help there too, and that's what most new receivers have.  I am thinking of getting a BHI DSP box to use with my "classic" radios.

The same way that government rebates help the electric car industry sell clean or zero emissions cars (even though the battery manufacturing and lithium mining industries are hopelessly toxic and environmentally disastrous), perhaps the government should give rebates to buyers of clean emissions transmitters.  We expect that a radio with a high-linearity and super clean transmitter PA will consume more power and cost more money than a less linear one, so a rebate would be the only incentive for most hams to buy a clean transmitter that gives themselves no obvious or immediate gratification other than the knowledge that they are doing something good for the (radio communications) environment.

73, Ed

Logged

K4EMF

  • Member
  • Posts: 413
Re: Choosing a rig and Sherwood's list
« Reply #71 on: May 18, 2021, 08:52:34 AM »

Dan Sherwood has done a lot of work to build his repository of test info. It's at http://www.sherweng.com/table.html for the few that are unfamiliar with it. He ranks rigs by ability to operate with close spaced interference....

I believe CW contesting is where maximum receiver performance is needed and Dynamic Range Narrow Spaced is the parameter of interest. I've owned several transceivers that did not hold up under 160 meter contesting. The two I've owned that were excellent for CW contesting are the Elecraft K3 and the Icom IC-7300 with narrow spaced dynamic range of 101 and 97 dB respectively. One of several that were nearly unusable under 160 meter contest conditions is the Kenwood TD570S at 69 dB. In the paper cited below, Bob Sherwood says 80 dB or better at 2 kHz (that is narrow spaced dynamic range) is needed for CW.   

Here's a link to the paper Transceiver Performance and how do we measure it?, by Bob Sherwood.

     "Contesters – DXers – Pileup operators need a good receiver for SSB and an even better receiver for CW."

Near the end of the paper he presents a the list Considerations in Choosing a Transceiver.

http://www.na0tc.org/lib/exe/fetch.php?media=technical:transceiver_performance_and_how_do_we_measure_it-_rob_sherwood_nc0b-285-techconnect-1w.pdf

Sherwood Receiver Test Data
http://www.sherweng.com/table.html

Thanks for sharing these guys.  I found them interesting and useful even if I don't fully understand it all.
I skimmed through the thread and there are any number of valid points made.  All of which I plan to take into account as I decide on my next radio.
Logged

KX2T

  • Member
  • Posts: 1545
Re: Choosing a rig and Sherwood's list
« Reply #72 on: May 28, 2021, 06:48:50 AM »

We I am sure glad you like your ole TR7, it was one of the top rigs that Drake designed and remember well when it hit the streets back then cause I worked for Harrison Radio then and had my order in for a TR7 but had to wait till customer orders were filled. The TR7 had a clean transmit signal but the VFO by todays standards was not as stable as today rigs, it had more internal noise from the different conversion stages plus with age most of the mechanical switching devices get noisy but still a milestone radio for its time. For those who want a better VFO and add more up to date flexibility to a TR7 there is a small company called Nobel Radio that makes a remote DDS VFO which adds far more flexibility to the 40 year old box so if you don't wanna give up on the old girl there is a fix. One of the remote VFO gives modern day ability to the TR7 plus added extras such as speech processor, sound card ability plus be able to hook up to a computer and go threw a logging program for point and click plus there top like vfo has an integrated pan adapter module, just go to there site and you can take your TR7 into the modern age and keep her plugging along. Another area were the TR7 had some shortcoming was the IF chain and even though there filters seemed somewhat sharp they had loss and blow by but here again this little company has 8 pole crystal filters which will here again improve the old girls shape factor kind of speaking. I find it very interesting that today even a small company can bring the best out of some of the best rigs from yesteryear not just make a replacement simple accessory but make that part far more advanced for todays modern usages.
Yes you  can breath new life into that good ole girl!
« Last Edit: May 28, 2021, 06:51:49 AM by KX2T »
Logged

K6BRN

  • Member
  • Posts: 2231
Re: Choosing a rig and Sherwood's list
« Reply #73 on: May 28, 2021, 10:24:14 AM »

The right transceiver is the one you enjoy.  And since some people contest, other rag-chew, some are mostly CW, others FT8,etc, what is most important in the radio varies by user.

Sometimes it's just the thought of owning and using exotic or state of the art gear, as many "latest and greatest" serial equipment owners on this forum do

In the '70's, I used to drool over the Heathkit SB-104, which looked like pure magic to me.  Catalog cruising was a popular cold winter's night bedtime reading activity and the Heathkit products caught my imagination.  We didn't have much money, so that was as close as I got to ownership.

Then the TR7 came later along with it's revolutionary up-converting receiver, I was in love again.  It was was a Rolls-Royce rig, very professionally done and a rig I could only dream about. Unfortunately, my budget was more HR-10B and later HW-101 (used, with CW filter).  Means came only later in life.

I don't have my HW-101 any more.  But I very fondly remember the QSOs I made with it and still have my paper log from those days.  My favorite mode was AMTOR.  THAT was a trick, since the radio VFO was so drifty.  And I had to build a SS interface for it that could drive my AMT-1 modem.

So - the "Best" radio can be different with everyone and likely changes over time.  The real question (test) is:  "Did it leave a fond memory?"  In that light, the HR/HX of budget gear from Heathkit was a success in my world. even though technically and operationally it was pretty poor.  The HW-101 was light years ahead of it - because the HW-101, despite its flaws, actually WORKED (most of the time) and gave many hours of enjoyment.

My modern equipment (analog/digital hybrid radios) are far more capable, reliable, stable and I've made many more contacts with them.  But nothing beat the original thrill of my used, rebuilt (by me), Heathkit HW-101.

Therefore the HW-101 is at the top of - "Brian's List"  :)

In a similar vein, my older brother had this 1967 Camaro ... ah ...well .. topic of another thread, perhaps!

Brian - K6BRN
Logged

AC7CW

  • Member
  • Posts: 1789
Re: Choosing a rig and Sherwood's list
« Reply #74 on: May 28, 2021, 03:01:40 PM »

The rig that I enjoyed the most was a single band [20Meter] single mode[SSB] Heathkit. All the choices were gone other than "is the band probably open?" I recall that it was a 200 watt rig but not sure. It was vacuum tube tech and I was able to repair and align it and all that... I'm looking at the modern rigs with problems with firmware updates and horrendous complications with trying to use external software and thinking that's not at all, in the least, what I want to do... so yeah I'd love to have a rig near the top of the list but only if it's pretty much turnkey... i've been computing since 1974, writing software and currently working in C++, I'm dealing with a certain level of learned helplessness really.  I do not want a hobby that makes that worse...
Logged
Novice 1958, 20WPM Extra now... (and get off my lawn)
Pages: 1 2 3 4 [5] 6 7 8   Go Up