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[KA4WJA]

Jim, et al,
I tend to agree with your sentiment here...
And funny you should write that, as some friends and I were just speaking along these lines the other night, on 80m.

1.5 kw into stacked yagi's up 200' is...'ok'...... but 5 kw into a dipole is a ...'no-no'.  Gimme a break.  Who cares how you get ur  ERP.

Anyway....so, I took some time writing all the below....and, now as I reread it / proof-read it, I wonder if it's worth it to post it all here, when all that needs saying is: 
using extreme high power should be frowned-upon, but if you choose to do it, please do it the right way --- keep your signal wicked-clean --- please.

But, I already spent the time writing it...so...
(Oh, and I'm not sure what all the arguing is about...but, since it isn't regarding anything that I posted, I'm not going to get involved in it....so, no worries.)

I'm just going to comment on / clarify my thoughts on, the big Dressler amps, some perils to consider if desiring to run hi-power, etc....I promise, even if I start off with a ramble, bear with me a minute ---- 'cuz I do get to a question.


1)  And, first off, a minor correction...
 Sorry about my typo earlier...my 4cx15000a pull is out of a Harris 740m....(not even sure there is a Harris 710?)


2)  And, yes....we have all been hearing the refrain regarding pre-distortion now for many years....I first learned of this, in detail, in the 1990's! 

[and, I am still looking forward to it....but, I also think we need to be realistic, even if it became available soon, how long would it take before a majority of HF signals on our bands had working pre-distortion?  10 years?  15 years? maybe less...maybe longer?  maybe decades?  So, while active/adaptive/digital pre-distortion IS a wonderful advancement, in my opinion, it's not really a viable solution today and this year (nor for next few years) to cleaning up the SSB signals on our phone bands....so, again, while I do appreciate this advancement, I'll not get wrapped-up in the wishing/hoping for it. ]

We have all been waiting/hoping for commercial amateur radio manufacturers to roll out pre-distortion now for more than a decade (even here on eham, starting back in 2012, some discussed Flex and Elecraft having pre-distortion "soon"...that was 10 years ago!)

But, except for the very-small, niche-market ANAN's (and Hermes) SDR's and the software running them, there still are no mass-produced ham rigs with pre-distortion!   {fyi, JRC does have pre-distortion in its big HF maritime shore stations and HF aviation ground stations....but they are wicked-pricey and require professional installation and set-up}

Now, yes...Icom has announced that the IC-7610 and PW-2 combination will have (spring/summer of 2023) pre-distortion....but that's it!!  And, that "combo" is apparently what will work....as the 7610 will not take in an analog RF sample, but rather will take in a digital reproduction sample of the PW-2's output, that will allow it to do pre-distortion corrections of the amp as well ---- placing the amp inside the pre-distortion loop, but only the PW-2 amp! 

And, when operated in their Class A mode (with NO ALC at all), years ago Yaesu did try to provide some transceivers with clean transmitters, but that's no longer the case as they gave up and no longer make radios with Class A PA's....

Now, many of us, including Rob Sherwood, have been saying for years and years (in my case for a couple decades) that on our phone bands it is our own dirty transmitters/amps that are our limiting factors in using the phone bands these days.....for the past decade or two, we cannot use all the capabilities / specs of our receivers, because of our transmitters! (and, while the ARRL finally did recently publish Rob's article regarding this, he and others have been saying it now for over a decade!!)

Please don't take this as another IMD rant....nope...

The reason I'm mentioning this here....well, should be obvious....but, in case it isn't:

If some hams wish to use significant high power, they damn well need to drive (not over-drive) their big amps with clean transmitters! 
And, this means, something the likes of a Class A exciter (without any ALC)....or perhaps a clean, modern, commercial maritime rig....or maybe a TS-830 or 32S-3, etc....or maybe a clean TR-7, etc....'cuz if you put a new, modern FT-101d or MP, etc. in front of a few KW's of amplifier, with a decent antenna, you're going to be a pariah on-the-air in damn short order!  (even if operated as proscribed, most of the modern Yaesu's over the past 10-20 years are pretty bad...and, anyone that hasn't yet heard the buckshot from the new 101's and 10's, you will...give it a few more months as they replace many of the surprisingly-good '7300's, on-the-air...)

Oh, and please could we all just chill a bit with looking at only the IMD3 numbers.
I mean, sure it's an easy (lazy) way to compare numbers, but in many instances it is very misleading!   
(of course, in some circumstances the IMD3 and IMD5 figures are all we have, as higher-order products of most vacuum-tube linear PA's fell-off quite rapidly.....so I do understand the reasons that some ignore the higher orders, but let's remember it is these higher-order products, 5th, 7th, 9th, etc. that cause significant issues on-the-air....although were never really an issue in years-gone-by with vacuum-tube PA's, with modern SS PA's in our rigs, these higher-order products no longer fall-off rapidly and hence have become an issue.)





BTW, this is particularly important for those hams who think some xxx rig has only a few db worse IMD3 numbers than yyy rig has....but fail to look at the higher order numbers where the yyy rig might have its higher order IMD products that fall off very quickly / disappear altogether (such as the classic 6146 tube final PA's of the TS-830 or 32S-3...or even the venerable TR-7...or a MarkV in Class A, w/ no ALC), and where the xxx rig might have higher order products that are 10-20db worse than that yyy rig!

Further, depending on voice/speech, while it is possible for IMD3 products to fall outside the rigs' passband, they are usually inside, or along-side, the passband skirts, and again depending on the voice/speech and adjustments AND frequency separation of the adjacent QSO, usually have minimal effect on adjacent QSO's, except for very-close-in adjacent QSO's (such as in contest environs)....with usually IMD5 being the most predominate product effecting the immediate adjacent QSO, along with IMD7....and, again depending on voice/speech and how the radio is adjusted, IMD7 and IMD9, etc. effecting QSO's farther removed from yours...but, again, with human-speech containing many complex tones/harmonics itself, our static-two-tone tests can be misleading....although, they're all we really have to look at / compare, so we do use the two-tone test numbers, just we need to remember that human speech is way more complex than 2 simple tones...

But, then we also have the pumping of the ALC systems in our "modern" rigs (as well as maladjusted rigs) causing lots of buckshot splatter, way up and down the band.....sometimes these spikes can be quite high (looking at some using a websdr, I've seen ALC-induced spikes / IMD show up +/- 8 to 10khz, at only 10db - 15db below the fundamental signal....yikes!)

Further we have those hams who want to see more output (or rather what to see the meter swing higher) and end up over-driving any amp they have.

If you combine all of these things, I think you'll see why anyone considering running high power needs to stop and consider what rig they're running, how they'll run it, and how they'll drive their big amp...otherwise they'll get a very bad rep in no time at all!

{Now, I'm pretty sure than Jim, Shane, etc. here, know this up/down and sideways.....but others reading this may think "hey, I got this new fancy rig....why do I need to worry about splatter"....or even worse, they say "what the heck is IMD?"....or even worse yet, "where do I send a check, for 10KW?"...}



3)  And, some of my fav info from Eimac....and why I love the high-gain and clean, linear output, as well as the simplicity and ruggedness of the 8877!  (yes ruggedness, with its 25 watts of grid dissipation, being three times that of a PAIR of 3CX800's)

{yes, Jim, et al, there are better tubes...like the 3x3, etc., with its wicked-rugged grid...but, in my opinion, for ~1.5kw amateur radio service, the 8877 is damn close to being a perfect fit....heck, if you have the power-supply and adequate cooling, it's a "brick-on-the-key", even at ~ 2500 watts out, and still damn clean n linear!}

From Eimac datasheet:

The Eimac 3CX1500A7/8877 is a rugged ceramic and metal power triode designed for use as a
cathode driven Class AB2 or Class B amplifier in audio or rf applications including the VHF/UHF band..

As a linear amplifier, high power gain may be obtained with excellent intermodulation distortion characteristics.

Low grid interception and high amplification factor combine to make the 3CX1500A7/8877 drive power requirements exceptionally low for a tube of this power capacity.

Also, if you can stand the heat of the high-idle current, have a look at the IMD possible from a 4CX1500b...after I saw that Alpha ended up putting a pair of them in the 8410, I thought how cool it would be to increase the cooling capacity of the Alpha 8410, rip out the processor/fancy display, run ~ 300ma per tube of idle current, and run those pair of 4cx1500b's to ~1800 - 2200 watts out, driven with a Class A exciter...that's ~ 2kw out with IMD3/5 of at least-50/-54db(PEP), with no pre-distortion!



Of course, I'd settle for the Alpha 77 at ~ 2500 watts out, driven with a Class A exciter:




And, in regards to what transceiver to drive your big amp with ---- just a few scans / food for thought...here's the FT-1000MkV in Class A (w/ no ALC), at 75 watts....that was used to drive the Alpha 77 just above:



If you're surprised by the MkV in Class A....here are a K3 (at 75 watts out) and a 32S-3...and, my own 44 yr old Drake TR-7 (in need of alignment):









4)  Also, in my sleepless haze, I posted the German language links, so here are the English language links:

The original, 4CX10000d, "Tsunami" Project amp (which is do-able and not "over-spec'd"... i.e. unlike the other/bigger "tsunami" amps, it will make its spec'd 15kw out, with a 4CX10000 and a 10kva plate transformer....I assume this is 'cuz the 4x10 is just a 4x5 with a larger plate cooler/fins...so, he can't push it as hard as the other tubes?):
http://www.dc9dz.de/en/tsunami.html

The bigger, 4cx15000a, "Tsunami" amp (which is advertised with exaggerated 60kw output):
http://www.dc9dz.de/en/tsunami60k.html

And, his huge, 4cx20000C, "Tsunami" amp (which is advertised with exaggerated 100kw output):
http://www.dc9dz.de/en/tsunami100k.html



5)  At the risk of contributing to some argument, I stand behind my words, that in my opinion, his SSB output specs on the bigger "60kw" and "100kw" amps, are "exaggerated".....but even if he runs the plate voltage up significantly, to try to make those outputs, instead of a nice clean signal, you get a crappy splatter-box! 

Those that wish to see some numbers....
Eimac shows an IMD3 of -48dbc for the 4CX15000a, and he specs a horrible -32db and we assume that's -32db(PEP), which is only -26dbc..

–32 dB or better  (with predistortion mode: better –47 dB)

  But, you'd be better off just driving the amp to a more normal output of 25kw - 30kw, and have better IMD than you'd have at 60kw out with pre-distortion.

I know, I know...using Eimac tube data sheets and their "typical" numbers is fraught with issues and I should not even be doing this here, especially 'cuz there's more to IMD/linearity than the tube!
But, I thought maybe a bit of reality was in order here, as I don't look forward to guys pushing their amps harder than they're doing now!

Now since, I'm familiar with the 4x15, I'm going to specifically write about the 4CX15000a "Tsunami" amp (which he specs at 60kw SSB out [sic]...but my thoughts here also correlate well if looking at the "100kw" output spec of his 4cx20000c tsunami amp)....if you ran the 4x15 tube at its Eimac spec'd max ratings (~ 60kw DC input), you could expect ~ 38 - 40kw output....

And if looking at Eimac's "typical operations" in Class AB1, Grid-driven RF amplifier (not an AF amp, nor modulator, but an RF amp in linear service, Class AB1),  at 42.5kw DC input, they show about 28.5kw output at "envelop peak or modulation crest", clean and linear, I assume...as, at lower plate voltages and output (with similar res tank load impedances), Eimac does show IMD3 and IMD5 at wicked-clean -49dbc and -45dbc....that's an IMD3 of -55db(PEP)....and, remember this was decades before "pre-distortion"!

Have a look see:



Now, I freely admit that I've only seen the 4CX15000a in commercial HF linear service, running 10kw out...and, I assume that some of you others have run significantly higher power from it....but, my point is, perhaps running 30 - 40kw from it is "okay" (depending on what you wish to accomplish and what IMD numbers you need to meet) ---- but spec'ing a multiband desktop HF amp to run 60kw SSB out from a 4CX15000a...in my opinion, just not legit. 

And, a few other "issues" I have with those bigger tsunami amps....with his high DC voltage on the plate, I suspect some wicked-high RF voltages, and he uses only a 15kv vacuum-variable tune cap?  And a 5kv load cap? [the Alpha 77, with ~3900v DC on the plate, uses a 7.5kv Tune cap] 
Should someone pony-up and buy one of these amps....my advice, tune-up carefully (and start at lower powers)....and don't try to load up into any swr.....'cuz you'll likely arc/burn up the tank circuit!   Yeah, it's a "desktop" amp....and, in my opinion, unless you've got a huge desk, you shouldn't try to build more than 5kw in a "desktop amp"....just doesn't make sense. 

Now, I'm not disputing that in amateur radio SSB service, exceeding "max ratings" of our tubes is de rigueur....and excepting in the all-too-oft cases of over-driving our amps ---- causing splatter.....exceeding tube manufacturers' max plate ratings by a small amount (maybe ~ 10% - 20%) for our SSB rag-chewing, etc., probably doesn't cause much of an issue...(except of course for those spending the $$$ for new tubes, 'cuz they pushed 'em way beyond "good engineering" / "good amateur practice"...and/or ignored grid current!)

But, with a plate transformer spec'd at 20kva, I just don't see this thing making 60kw SSB output!  I mean, even at 67% eff, that would require about 90kw+ DC input!  (and, 140+kw DC input, for his "100kw" output amp)

And, for the "60kw amp", I see that he specs 12kv on the plate (20% above the max spec of 10kv), but with only a 20kva transformer (maybe ~8.5 to 9kvac @ ~2.5amp CCS?), so while he may be pushing the power supply heavily and maybe he gets 12kv DC @ 5amps?  Maybe?   But, that's only 60kw DC input, how in the heck do you get more than 40kw outa' that? 
And, probably not even that much....my guess is that it's more like a 25-30kw SSB out?

Of course, if this amp had a 40kva transformer....or if whatever plate supply it had, allowed 90kw+ of DC input, then I'd say in our amateur SSB service, 60kw output from a 4cx15000a is do-able, I suppose....but.of course, nothing that I'd recommend, but semi-do-able....certainly can't think of a better way to make oneself a pariah on-the-air with 50-60kw out, splattering up/down the band, but hey maybe some CB'ers hams desire that?


Now, maybe Jim or Shane, et al, have the answer....but I don't....that's why I'm asking the question.

Is there a way to cleanly get 60kw SSB out of a 4cx15000a amp with a 20kva plate supply (or 100kw out of a 4cx20000c amp with a 30kva plate supply)?

My answer is: No...but, I'm willing to learn, so if I'm wrong please educate me...


My advice....if you desire 50 - 100kw out in linear service (SSB) on the HF bands, have a go at building a 4CX40000C, with a 100kva plate transformer....or maybe a pair of the 4CW25000a's (the water-cooled version of the 4CX15000a's) ---- always wanted a quiet, water-cooled amp.....as either the 4x40, or a pair of 4xw25's, will be nice and linear!   But, please use a Class A IPA and Class A exciter. 



Myself, except for dreaming and late-night on-air BS sessions, I never thought of needing more than a 5kw desktop amp...
Yeah, way back when, I had dreams of building a single-band, 80m amp, with the 4CX15000a, with a 25 - 50kva CCS "pole-pig" plate supply....grid-driven w/ ~ 100 - 200 watt Class A IPA, and having a nice wicked-clean 15-30kw out, with "brick-on-the-key" CCS capability....that was just a dream.   Now-a-days, my 4x15 is just a conversation piece.


I hope my words don't cause much controversy, and hope my questions are taken with the polite intent I desired. 

73,
John,  KA4WJA

[KA4WJA]

A bit of a "twist" in the story of the Dressler Tsunami amps!

I just did a quick search, and what-do-you-know....back in 2015 he advertised the big 4CX15000a Tsunami amp at 40kw output!   (with a 20kva transformer....but spec'ing the B+ at 10kv, rather than the 12kv on the current website)
For a price of ~ 40,000 euros.

https://qrznow.com/dc9dz-project-tsunami-40k-power-amplifier-pa-using-4cx15000aa/

It looks like while his original "tsunami" amp (with the 4CX10000d), that he designed/built as a project for a wager of a case of beer, was a working amp....
It's possible that these other amps (the big 40kw, 60kw, and 100kw) are vaporware? 
'Cuz there aren't pics of them, just pics of the original "Tsunami" project amp.

And, his new "60kw" advertised output is just the same amp, driven harder?  With truly crappy IMD....heck even at 40kw out, his IMD specs aren't great...


Oh well, lots of discussion....maybe good...maybe all for not?
Whichever the case, if he does build these bigger Tsunami amps, let's just hope anyone that buys one doesn't drive it too hard!   


73,
John,  KA4WJA

[VE7RF]

Dunno where u read the drivel about a MK-V in Class A..with NO alc.   I listen off freq on a 2nd MK-V, while TX'ing on the 1st MK-V....  and don't hear much, if any difference. 

Run any xcvr with NO ALC showing and u will end up with ZERO talk power.  Peak to RMS ratio with typ male voice is 22.5 db.  To put that into perspective, peak to RMS ratio on a sine wave is 3 db.  1200 watts pep = 2400w peak.   100 w incandescent  light bulb = 200 watt peak.   Some eng books claim 14.5 db peak to average ratio.   Try operating any xcvr with no alc (amp in standby), with full pep still showing on a pep meter...and ur average power out is dick, through the floor.

Forget that.  'Mr Tsunami'  as he is known world wide sells the real deal, it's not vapor wear.  However his 'ratings' are on the BS side of reality.   Well u might, if u used ZERO ALC..and talk power was through the floor...and pep to average ratio was 10-14 db.   To put it all into perspective, my 1290 w pep out / 375 watts average output has a 5.37 db pep to average ratio.

With loads of processing, average DC plate current is 1/2 of key down CXR. (output side, average PO is 29% of pep).   Any 30 kva CCS plate xmfr is good for 60 kw pep INPUT..and maybe 36- 40 kw pep output.... that's it.  Any more, and V regulation will suffer if using single phase 60 hz.  His stuff runs on 3 phase, 50 hz, but the general rule still applies...pep input is aprx double the CCS rating of the plate xfmr.    The biggest advantage of 3 phase is..... the raw DC is only 5.2%
 ripple..... (vs 67% with single phase FWB /FWCT / FWD).  Ripple on 50 hz  3 phase = 300 hz (360hz with 60 hz, 3 phase).  Ripple on single phase  50 hz =   100 hz  ( 120 hz when using single phase 60hz power..like in NA).

I would take his ratings..with a huge grain of salt.  You got lotsa other issues to deal with in any grid driven tetrode..with handles tube amp.   Like the huge input C..which is directly in parallel with his 450 ohm resistor..has to be cancelled out..with an equal amount of  XL..which equates to large values of coil esp on the lower bands.   I just went though all of this with a buddy's  4x15 amp..and also a 4x10.  Instead of the 1:9 xfmr..feeding a  450 ohm globar, we instead used a 500 ohm globar..then used a simple, adjustable PI net to match the 50 ohms.  Then the whopping 160 pf of input tube C ( 110 pf on a 4x10)   simply gets absorbed by the C2 cap on the PI input.  That works on all bands..except 15m-10m, where a tiny coil has to be switch in parallel with the 500 ohm resistor.  Then no neutralization required.     If they have to be neutralized, it's a mess to deal with. 

Tetrodes can end up a complicated mess... and a lot of protection required, like plate and screen over current. Lose the B+..and with screen V and bias V still  present..and drive applied..all hell breaks loose..with screen current pegged.

There is big..then there is too big imo. Think of everything downstream.  With '200 amp' residential service, the practical upper limit is 10-15 kw pep out on ssb / cw....and  10 kw out on data modes.   A dead simple  GG triode will suffice, like a 50 ohm input  3x6, ( which has 7.2  to 8 kw of CCS anode diss with 320 cfm, instead of 204 cfm), more than ample for the job..with low imd. But it requires a  500-600 w  ipa..which everyone has anyway, moot point. 

Start with 20+ kw output, then you are really looking at '400 amp' residential service.  This is where the problems start up. 20 kw is probably the max safe limit for 7-16 DINS.   Next up from that is the 1 5/8"  EIA flange connector's.   Now we are getting into silly territory.  This next 2-3 db is gonna cost some serious $$$$.  Called..diminishing returns.   Some  will mount the  yagi 5-6' above the top of the tower, then use 3-4 large ( 3-4'  diam) loops, like a giant coil spring, stood vertical.  Typ used with 7/8" and bigger heliax.  Only way to rotate the yagi, with non flexible coax.   You see similar used on mobile TV trucks. They raise the mast..and the coax trails up like a giant slinky.

BTW, the 4x5 / 4x10  idles at 500 ma.  The 4x15 idles at 1000 ma.  Dunno abt the 4x20.   The idle power is insane on tetrodes, never mind the blower power.   Then the heat has to be dumped to the outdoors, via custom ducts.   Biggest vent hose is 8" OD.   Any bigger, and 2 are used..or custom duct sheet metal work.

Sure, this is all doable, but the logistics are off the deep end on any multi band amp.  Check out Kintronics prices on their
 tubing style roller coils.   They have em in 20amp ( 1/2" x .090" edge wound ribbon)..then 30 amp ( 3/8" tubing)...40 amp (1/2"  tubing)..... 50 amp  (5/8" tubing)....and also 60 amp  (3/4" )  and finally  80 amp  ( 1" tubing).    Prices are beyond nuts. 

Take the current ratings with a grain of salt.  I suspect they are for 1 mhz / AM broadcast.   Just 9 amps will get a 1/4"  tubing coil pretty hot on 15m band.  Bandswitches are rated for DC / 60 hz.... and are de-rated for RF freqs.

The german prices are in Euro's..and very expensive.  You gotta know how to repair em.... on site.   The shipping cost would be stupid expensive..... and hope they get it to you...intact.

And you want to operate  VOX..or heaven forbid  QSK CW.   Well it is doable up to 45 kw on 10m..with a flat swr...including QSK. 

There is practical, then there is off the deep end.   A mono band hi power amp is one thing, but a multi band amp is another issue.  Then toss in ant switches, DL, protection devices, RFI, ants that will handle the power, corona etc.   Imagine a MM contest station, good luck with inter station interference.   Imagine several of these big amps...all running at once.   They are really a single band at a time deal.

For real simplicity, a 3x3 will do  1.5 kw with 50w of drive. 2.5 kw with 100w of drive.....and   5 kw with 200w.   Sure, the 8877 is a nice tube, but I'm not paying $2K  for one ( and not $2.9 k that Richardson's wanted last year..before they dropped the price back down to $2k).

End of rant.   Go for it.

[KA4WJA]

Jim....didn't mean to hit a soft spot?  Sorry.

1)  Where did I get the info on the '1000?   
In addition to hearing the ALC-induced buckshot, years ago, on-the-air myself (un-modified rigs), and still hear it these days from more modern Yaesu's....I've also read (and seen the scans) of the results from SM5BSZ....and also got the scans of the FT-5000 (in Class A) from NC0B, Rob Sherwood, showing significant difference between Class A with no ALC and Class A with just 1/2 of Yaesu-recommended ALC....(and Rob did white noise tests, not 2-tone....and SM5BSZ used human-voice testing, rather than 2-tone....just so nobody will cry out that "two-tone tests are crap", I will look for the scans when I can ---- maybe this week?)

If you'd like them, it will take me a while to find 'em, but I can post some of them here....and, you can see what we see....

I suspect with your mod'ed '1000's you don't have this issue, but I have heard it myself personally, right here in Florida....
One example, had a friend (now a SK) who bought a MkV years ago, drove it (~ 35 - 40watts, I think?) into an Alpha 87 to about 1800 watts out....then had him run it in Class A ('cuz I was such an IMD weanie, even way back when) to "prove" how "great" Class A was....well, I ended up with a bit of egg on my face, 'cuz while his close-in IMD (3rd, 5th, 7th?) was low (he was only ~ 30 miles from me, so he was very strong on 80m), his signal wasn't as narrow as I had expected and he still had significant buckshot out there....

It was a couple years later than I saw some info from Rob about the '1000's ALC issues, and then a few years later (2005?) read the tests of SM5BSZ and then a couple years after that, I also got scans from Rob of the FT-5000 in Class A, with and without ALC....and, it all started to make sense.

Further Rob has also commented in some more recent reports on the poor ALC performance of the new FTdx-101's, although I don't have scans of those....

Also, I think (it's late, so don't hold me to this last point), I think Adam Farson, VA7OJ, also has noted the Yaesu ALC issues / pumping, over the years, yes?

So, while your experiences with them might be different (and don't get me wrong, I do love the MkV), my experiences and my research shows issues with their spectral purity with ALC.

I hope that answers your question about the "drivel"?    But, no worries here, we can politely disagree, and the world won't end.



2)  As for ALC being the only way to attain talk power? 
Really?  In what world is that? 
'Cus in the world I live in we see plenty of talk power without ALC....ALC is a fairly lazy way to attain talk power, and shows the laziness of what passes for SSB design these days.  (sorry Yaesu, but yes I'm talking about you all)

Speech compression / speech processing, etc. has been done well for decades, and this is certainly much better at producing better peak-to-average SSB than ALC.

But, even without speech processing, decent design audio stages and balanced modulators (some things I don't hear much on-the-air these days....heck, in recent years, with so many running all-knobs-to-the-right, I think most of the design engineering is just "this is what we did, and it worked....let's do it again, and add more "umph" and we'll sell the crap outa' these rigs!") (....these days it seems it's all about "meter swing", "punch" and "talk power"...ugh!)...better designs of these, as well as PA's, can actually provide decent, clean SSB signal, with decent peak-to-average power, without over-driving succeeding stages, nor causing distortions, we just don't see/hear it much anymore ....and, while many prefer adding some processing, I only do so if needed....and I hold my own on-the-air. 

I don't have the time (nor a good enough mood) to do some math or look for some notes, so sorry if it sounds like I'm dodging the issue....but, geeze Jim you know that speech processing (if done well) is much better than ALC to produce SSB Talk Power.


Hey, just an fyi...
This has nothing to do with ham radio / eham / etc.....but, I'm not in a very good mood this week, and don't wish to go off on an unrelated rant here, so...
So, I'll just say that I completely 100% disagree with you on this.

In my opinion, in my experience, ALC is not needed to attain decent talk power....in my opinion it is used in lazy ways.
Sure it IS used in many modern amateur SSB transmitters to attain talk power (but, that does not make it correct, nor even close-to making in "necessary"!)....yes, unfortunately used by some professional engineers....some engineers in JA (Yaesu, etc.), might disagree with me, but I think they would come around and admit the error-of-their-ways, if they didn't have bean-counter-bosses... LOL


3)  As for Tsunami, okay not vaporware....just BS output numbers.

Yes, I agree, a 30kva plate transformer is good for ~ 60kw DC input and ~ 35-40kw SSB out....but, he is showing a 20kva transformer for a 60kw OUTPUT amp (w/ the 4CX15000a)....and the 30kva xformer for a 100kw OUTPUT amp (w/ the 4CX20000c)....and, that is pure BS / exaggeration...

His numbers just don't work....sure 3-phase ripple advantage / easier filtering, etc....but, it's good that we agree that he is not getting 60kw SSB out of a 4cx15000a, with a 20kva xformer.....('cuz this would be like saying ya' could get 6kw out of the original Alpha 77, with the small/original 2kva xformer....[not the 77sx with the factory internal 3.4kva xformer]...just ain't gonna' happen....3kw, sure....but not 6kw...)



4)  BTW, on a side note, I did just recently acquire a big PW Dahl 9kva plate transformer....it's not huge by "tsunami" standards, but to my standards it's big/heavy/powerful....it weighs in at 127lbs....it's the PW Dahl A77S-X2 OUTBOARD PLATE 3 AMP / 9KVA OUTBOARD PLATE TRANSFORMER.... Not sure if I'll actually connect it to one of my 77Sx's, but since 95% of my operating is 80m SSB, and I'm in South and Central Florida, you never know.

And, I measured the secondary resistance on this beast, and from 0 to 1800 tap = 2.35 ohms, and 0 to 3000 tap = 4.1 ohms....and I've seen some Youtube videos showing EPD transformers significantly higher (like 12 - 40 ohms)....so, whether I end up using this or not, it will probably appreciate in value (certainly already got an offer for higher than what I paid, and I just bought the darn thing a week or two ago, and have already gotten emails about it...)



5)  As for those considering extreme high-power....well, to each their own, I stand by my words (using extreme high power should be frowned-upon, but if you choose to do it, please do it the right way --- keep your signal wicked-clean --- please)....but let me be even more strident here....it should be heavily frowned upon, but if someone does decide to do so, they need to make damn sure their signal is clean!

And, yes, I agree there are a wealth of other things to consider, other than primary AC Mains power, cables, antennas, transmit RFI, etc...thanks for reminding me of the other (internal) design issues....more reasons why my 4x15 is just a conversation piece!  And, why commercial Harris 10kw xmitters are so pricey!   (And, why I'm happy with a pair of 8877's)


BTW, some won't believe me, but late last year I bought a new (NOS) Eimac 8877 and a new in bag (NOS) YU-158, for only ~2.6db more than RF Parts sells new 3-500z for!  If I find anymore, for those prices I'll let you know, but don't hold-your-breath!  (and, Richardson quoted me $1800 each, for a pair....so, thank goodness I have 4 in two amps, and now 4 spares, as well.)


Sorry, gotta go...some family matters down here....that I'm dealing with...gotta try to sleep.

73,
John,  KA4WJA

[KD6VXI]

If you are going to run 10 dB over legal limit, your IMD has to be 10 dB better than everyone else.

K1JJ a couple years ago built an ultra linear amplifier chain.  It was at or near -50 dB down at legal limit.  He found that it was very dependent on getting the load and tune set correctly.  Improper loading would kill it.

--Shane
WP2ASS / ex KD6VXI

(post Fiona.  Was a doozy here, but not as bad as Puerto Rico!!!)

[KA4WJA]

Shane,
Glad you survived Fiona.

(post Fiona.  Was a doozy here, but not as bad as Puerto Rico!!!)

5 years ago, my late brother, who was then living on Hassel Island (off Charlotte Amelia), survived the ~ 175 - 180mph winds of Irma, while huddled with friends on Water Island, St. Thomas.
His 2nd floor concrete-block apartment (on Hassel Is.) was partially destroyed....and lost most of his possessions (but, his Boston Whaler, filled with sand and water, survived on the hard, tied down to palm trees and the building foundation).
He spent the next ~10 days (with no electricity, and only hurricane supplies of bottled-water and canned-food) trying to get out of St. Thomas....he finally got on a boat to St. Croix, and by incredible luck got a flight out-of-there, to Florida, a day later....
A day or so after arriving here in Florida, we heard / saw Maria hit Dominica, etc....and then were glad to see it stay a bit south of St. Thomas...
But he was really glad he was here (with air cond, back-up generator, etc.).

Again, glad you're okay.

73,
John,  KA4WJA 

[KD6VXI]

Thanks....  Glad your brother was able to get off the islands soon enough.

St Croix was devestated by Maria, for more reasons than one.   When Irma hit north of us, we threw as much supplies as possible to St Thomas and St John.  So, naturally, when Maria hit here, we had little to fall back on.

The islands stick together, and Puerto Rico really helped where they could.

I didn't live through them, I was stateside fearing earthquakes and wildfires in California then.  But the locals never forget.

I'd had worse conditions when I lived in California with the winds.  I believe the highest wind speed here was on the eastern coast of the island, around 70 mph.  When I lived on a 6500 foot mountain above the Mojave desert, 100 mph was easy.

I came home one day and found my vertical a mile away grrrrr.  It was in perfect condition, just a mile away!

We had big rain there, but when you woke up, it was snow.  So, different.

Fiona was easy on us.  It got us ready for a storm.  It was an easy one to get me used to the island and the storm 'culture' here.

But, I did have to take my DX Commander down!  Grrr boo hiss hiss!

Again, Tha KS for the kind words, and glad your brother got out after the storm.

--Shane
WP2ASS / ex KD6VXI

[N0UN]

"High voltage" - they say it's contagious...   

N0UN

[KC0W]

 That’s a real beauty Wayne. What is the story behind it?

  Tom KH0/KC0W

[N0UN]

That’s a real beauty Wayne. What is the story behind it?

  Tom KH0/KC0W

A great eyeball QSO story Tom. Many chapters over several decades.




N0UN

[KA4WJA]

Jim, et al,
1)  I'm pretty distracted by some family matters, so it's taken a while to get back here....and, as I also don't want to drift your thread too far, by "good" luck I only have some of the info I was looking for, in my laptop.

Dunno where u read the drivel about a MK-V in Class A..with NO alc.   I listen off freq on a 2nd MK-V, while TX'ing on the 1st MK-V....  and don't hear much, if any difference.

I have most of what I mentioned here...(see below)

Jim....didn't mean to hit a soft spot?  Sorry.

1)  Where did I get the info on the '1000?   
In addition to hearing the ALC-induced buckshot, years ago, on-the-air myself (un-modified rigs), and still hear it these days from more modern Yaesu's....I've also read (and seen the scans) of the results from SM5BSZ....and also got the scans of the FT-5000 (in Class A) from NC0B, Rob Sherwood, showing significant difference between Class A with no ALC and Class A with just 1/2 of Yaesu-recommended ALC....(and Rob did white noise tests, not 2-tone....and SM5BSZ used human-voice testing, rather than 2-tone....just so nobody will cry out that "two-tone tests are crap", I will look for the scans when I can ---- maybe this week?)

If you'd like them, it will take me a while to find 'em, but I can post some of them here....and, you can see what we see....

I suspect with your mod'ed '1000's you don't have this issue, but I have heard it myself personally, right here in Florida....
One example, had a friend (now a SK) who bought a MkV years ago, drove it (~ 35 - 40watts, I think?) into an Alpha 87 to about 1800 watts out....then had him run it in Class A ('cuz I was such an IMD weanie, even way back when) to "prove" how "great" Class A was....well, I ended up with a bit of egg on my face, 'cuz while his close-in IMD (3rd, 5th, 7th?) was low (he was only ~ 30 miles from me, so he was very strong on 80m), his signal wasn't as narrow as I had expected and he still had significant buckshot out there....

It was a couple years later than I saw some info from Rob about the '1000's ALC issues, and then a few years later (2005?) read the tests of SM5BSZ and then a couple years after that, I also got scans from Rob of the FT-5000 in Class A, with and without ALC....and, it all started to make sense.

Further Rob has also commented in some more recent reports on the poor ALC performance of the new FTdx-101's, although I don't have scans of those....

Also, I think (it's late, so don't hold me to this last point), I think Adam Farson, VA7OJ, also has noted the Yaesu ALC issues / pumping, over the years, yes?

So, while your experiences with them might be different (and don't get me wrong, I do love the MkV), my experiences and my research shows issues with their spectral purity with ALC.

I hope that answers your question about the "drivel"?    But, no worries here, we can politely disagree, and the world won't end.

2)  Again, I accept that we can disagree....just letting you know what experiences I've had with this (my friends MkV, and hearing many "modern" Yaesu's on-the-air)....and, "where" I got the more detailed info....

---- I read his paper years ago (15+ years ago, I think), from SM5BSZ....and I do have his ALC and IMD info on the FT-1000D (not the MkV....my error), showing significant issues with Yaesu's ALC system and how adjusting gain so as to have no ALC at all and using the speech processor, produces excellent "talk power" (good average-to-peak ratio) and a nice clean / low-IMD signal without adverse splatter...(of course, use of speech processing isn't necessary if you accept weaker average-to-peak ratios) 
Have a look, human voice saying "Aaaaa"...

FT-1000 with ALC:


FT-1000 without ALC and without speech processing:


FT-1000 without ALC, with speech processing:



---- As well as have a link to his (SM5BSZ) extensive tests and discussion on the perils of ALC use in modern ham radios...please have a look:
http://www.sm5bsz.com/dynrange/alc.htm


---- I have Rob Sherwood's comparison of the FTdx-5000MP in Class A w 1/2-scale ALC, versus no ALC.  Have a look:



---- And have his report, mentioning the ALC of the FTdx-3000, '5000, '950, etc...

The ALC of the FTdx-3000 operates like all the Yaesu rigs I have used recently, including the FTdx-5000D, the FT-950 and this new FTdx-3000. The time constant is very fast, and Yaesu has purposely made this design choice to enhance its speech processing. Personally I think processing should all be done either in the IF (RF compression or RF clipping) or in DSP, but not with the ALC. In the case of the 5000D, the fantastically clean signal one can put on the air when the exciter is in class A is degraded significantly when ALC is used even to a modest amount.

Don't have the notes on the FT-1000MkV....but, as I have posted before (see my post above) I do have the MkV in Class A barefoot (at 75 watts out), versus running it thru an Alpha77Dx ( at ~ 2500w out)...
Perhaps, my memory conflated Rob's MkV Class A scans, with his '5000 Class A scans (with ALC versus 1/2-scale ALC)?   
Sorry about that...but, since my late friend had an "unexplained" wide signal in Class A with his MkV, and with Leif's work/tests of the '1000D combined with both the test results and reports published by Rob about the '5000, '3000, 950, etc., I assumed an (unmodified) MkV suffered the same issue with its ALC....and, unless I see otherwise, I will continue to assume this.


---- Adam Farson, VA7OJ, has also written of these issues with Yaesu ALC's.....I just happen to have his notes on ALC compression tests and the '991a...

ALC compression tests: The purpose of these tests is to identify increased transmitter IMD caused by ALC action at high baseband levels.... Severe ALC compression can be seen in Figure 4.

 

The only concern encountered during the lab tests was ALC compression at power output levels approaching full rated output. This degrades transmitter IMD performance, especially 3rd-order.

 

----  And, I've been hearing many new FTdx-101d/MP's (and '10's) on the air these days, that could be somewhat decent (or close-to decent) in regards to IMD/spectral purity....but most have pretty significant ALC pumping/compression, and lots of splatter and buckshot (caused by the crappy / lazy Yaesu ALC).


---- Not to mention the "overshoot" issues causing amp overdrive and further splatter on initial syllables of words, which also contributes to the buckshot....
Here is Rob Sherwood's scope image of the FTdx101D's overshoot (which supposedly has been only slightly improved with firmware upgrades?):   




3)  So, unfortunately while I do have the scans for the FT-1000D, I do not have scans specifically showing the MkV with no ALC versus it with ALC...(I honestly thought I did have them... )



4)  And, btw, on a somewhat side note...

Almost 20 years ago, reading SM5BSZ's wonderful papers on ALC (and a couple others) made me realize that much of the "modern" SSB transmitter designs we've been using are rather lazy efforts....now, I'm not an RF design engineer and felt hesitant to go out and overtly criticize these designs, but as you see I got past that hesitancy.    hi hi

Especially, now-a-days, with the nice modern 101d/MP's and 10's having their transmit performance ruined by piss-poor ALC's....and Yaesu's (and others as well) insistence that ALC is "necessary", when we could set drive and gain levels ourselves, and adjust processing as needed to maintain good average-to-peak ratios.

Just saying, this isn't a new issue....been with us for decades....and, as with piss-poor transceiver PA's and their IMD, maybe it's time we hams stood up and said "No....not going to spend my money on a radio that splatters, or has a poor ALC, etc."...yes?




Oh well, no worries....I'm not gonna' go off on a rant here, nor drift your thread....just answering the question as to "where" (in addition to actually hearing it on-the-air myself) I heard about Yaesu (and others) ALC issues....so, there ya' go, take it for what it's worth...
I posted of my own personal experiences with a good friend with a MkV and his ALC, and now have added the info from Leif, Rob, and Adam....
So, while others may have different experiences, that's fine....these are mine. 

Gotta' go.

73,
John,  KA4WJA

[VE7RF]

Jim, et al,
1)  I'm pretty distracted by some family matters, so it's taken a while to get back here....and, as I also don't want to drift your thread too far, by "good" luck I only have some of the info I was looking for, in my laptop.

Dunno where u read the drivel about a MK-V in Class A..with NO alc.   I listen off freq on a 2nd MK-V, while TX'ing on the 1st MK-V....  and don't hear much, if any difference.

I have most of what I mentioned here...(see below)

Jim....didn't mean to hit a soft spot?  Sorry.

1)  Where did I get the info on the '1000?   
In addition to hearing the ALC-induced buckshot, years ago, on-the-air myself (un-modified rigs), and still hear it these days from more modern Yaesu's....I've also read (and seen the scans) of the results from SM5BSZ....and also got the scans of the FT-5000 (in Class A) from NC0B, Rob Sherwood, showing significant difference between Class A with no ALC and Class A with just 1/2 of Yaesu-recommended ALC....(and Rob did white noise tests, not 2-tone....and SM5BSZ used human-voice testing, rather than 2-tone....just so nobody will cry out that "two-tone tests are crap", I will look for the scans when I can ---- maybe this week?)

If you'd like them, it will take me a while to find 'em, but I can post some of them here....and, you can see what we see....

I suspect with your mod'ed '1000's you don't have this issue, but I have heard it myself personally, right here in Florida....
One example, had a friend (now a SK) who bought a MkV years ago, drove it (~ 35 - 40watts, I think?) into an Alpha 87 to about 1800 watts out....then had him run it in Class A ('cuz I was such an IMD weanie, even way back when) to "prove" how "great" Class A was....well, I ended up with a bit of egg on my face, 'cuz while his close-in IMD (3rd, 5th, 7th?) was low (he was only ~ 30 miles from me, so he was very strong on 80m), his signal wasn't as narrow as I had expected and he still had significant buckshot out there....

It was a couple years later than I saw some info from Rob about the '1000's ALC issues, and then a few years later (2005?) read the tests of SM5BSZ and then a couple years after that, I also got scans from Rob of the FT-5000 in Class A, with and without ALC....and, it all started to make sense.

Further Rob has also commented in some more recent reports on the poor ALC performance of the new FTdx-101's, although I don't have scans of those....

Also, I think (it's late, so don't hold me to this last point), I think Adam Farson, VA7OJ, also has noted the Yaesu ALC issues / pumping, over the years, yes?

So, while your experiences with them might be different (and don't get me wrong, I do love the MkV), my experiences and my research shows issues with their spectral purity with ALC.

I hope that answers your question about the "drivel"?    But, no worries here, we can politely disagree, and the world won't end.

2)  Again, I accept that we can disagree....just letting you know what experiences I've had with this (my friends MkV, and hearing many "modern" Yaesu's on-the-air)....and, "where" I got the more detailed info....

---- I read his paper years ago (15+ years ago, I think), from SM5BSZ....and I do have his ALC and IMD info on the FT-1000D (not the MkV....my error), showing significant issues with Yaesu's ALC system and how adjusting gain so as to have no ALC at all and using the speech processor, produces excellent "talk power" (good average-to-peak ratio) and a nice clean / low-IMD signal without adverse splatter...(of course, use of speech processing isn't necessary if you accept weaker average-to-peak ratios) 
Have a look, human voice saying "Aaaaa"...

FT-1000 with ALC:


FT-1000 without ALC and without speech processing:


FT-1000 without ALC, with speech processing:



---- As well as have a link to his (SM5BSZ) extensive tests and discussion on the perils of ALC use in modern ham radios...please have a look:
http://www.sm5bsz.com/dynrange/alc.htm


---- I have Rob Sherwood's comparison of the FTdx-5000MP in Class A w 1/2-scale ALC, versus no ALC.  Have a look:



---- And have his report, mentioning the ALC of the FTdx-3000, '5000, '950, etc...

The ALC of the FTdx-3000 operates like all the Yaesu rigs I have used recently, including the FTdx-5000D, the FT-950 and this new FTdx-3000. The time constant is very fast, and Yaesu has purposely made this design choice to enhance its speech processing. Personally I think processing should all be done either in the IF (RF compression or RF clipping) or in DSP, but not with the ALC. In the case of the 5000D, the fantastically clean signal one can put on the air when the exciter is in class A is degraded significantly when ALC is used even to a modest amount.

Don't have the notes on the FT-1000MkV....but, as I have posted before (see my post above) I do have the MkV in Class A barefoot (at 75 watts out), versus running it thru an Alpha77Dx ( at ~ 2500w out)...
Perhaps, my memory conflated Rob's MkV Class A scans, with his '5000 Class A scans (with ALC versus 1/2-scale ALC)?   
Sorry about that...but, since my late friend had an "unexplained" wide signal in Class A with his MkV, and with Leif's work/tests of the '1000D combined with both the test results and reports published by Rob about the '5000, '3000, 950, etc., I assumed an (unmodified) MkV suffered the same issue with its ALC....and, unless I see otherwise, I will continue to assume this.


---- Adam Farson, VA7OJ, has also written of these issues with Yaesu ALC's.....I just happen to have his notes on ALC compression tests and the '991a...

ALC compression tests: The purpose of these tests is to identify increased transmitter IMD caused by ALC action at high baseband levels.... Severe ALC compression can be seen in Figure 4.

 

The only concern encountered during the lab tests was ALC compression at power output levels approaching full rated output. This degrades transmitter IMD performance, especially 3rd-order.

 

----  And, I've been hearing many new FTdx-101d/MP's (and '10's) on the air these days, that could be somewhat decent (or close-to decent) in regards to IMD/spectral purity....but most have pretty significant ALC pumping/compression, and lots of splatter and buckshot (caused by the crappy / lazy Yaesu ALC).


---- Not to mention the "overshoot" issues causing amp overdrive and further splatter on initial syllables of words, which also contributes to the buckshot....
Here is Rob Sherwood's scope image of the FTdx101D's overshoot (which supposedly has been only slightly improved with firmware upgrades?):   




3)  So, unfortunately while I do have the scans for the FT-1000D, I do not have scans specifically showing the MkV with no ALC versus it with ALC...(I honestly thought I did have them... )



4)  And, btw, on a somewhat side note...

Almost 20 years ago, reading SM5BSZ's wonderful papers on ALC (and a couple others) made me realize that much of the "modern" SSB transmitter designs we've been using are rather lazy efforts....now, I'm not an RF design engineer and felt hesitant to go out and overtly criticize these designs, but as you see I got past that hesitancy.    hi hi

Especially, now-a-days, with the nice modern 101d/MP's and 10's having their transmit performance ruined by piss-poor ALC's....and Yaesu's (and others as well) insistence that ALC is "necessary", when we could set drive and gain levels ourselves, and adjust processing as needed to maintain good average-to-peak ratios.

Just saying, this isn't a new issue....been with us for decades....and, as with piss-poor transceiver PA's and their IMD, maybe it's time we hams stood up and said "No....not going to spend my money on a radio that splatters, or has a poor ALC, etc."...yes?




Oh well, no worries....I'm not gonna' go off on a rant here, nor drift your thread....just answering the question as to "where" (in addition to actually hearing it on-the-air myself) I heard about Yaesu (and others) ALC issues....so, there ya' go, take it for what it's worth...
I posted of my own personal experiences with a good friend with a MkV and his ALC, and now have added the info from Leif, Rob, and Adam....
So, while others may have different experiences, that's fine....these are mine. 

Gotta' go.

73,
John,  KA4WJA

I would take what Farson sez with a huge grain of salt.  He's a 100% Icom fan boy from day 1.  He's into the stone age with the 4 x 250 w SS pa's to make a 1 kw pa.  Since he got zapped with screen V years ago, he won't go near a tube amp.

I own 2 x MK-V's. Other than the myriad of ESSB mods, no mods done to the ALC setup.  I'm not seeing or hearing increased imd, with or without ALC...using class A.  Why would it ?  It's already in class A..and sucking 10 amps of idle current at all times.   Driving an amp, while running the xcvr in Class A.... then the limiting factor is the amp, NOT the xcvr.   If you want to evaluate the xcvr in class A, don't test by driving an amp with it.  It's a systems approach.  Most folks don't understand the concept of how to tune up a GG triode amp, never mind a grid driven amp.  Overdrive..and under loading a GG triode amp both produce the same result, excess grid current..and splatter.  Note you can easily splatte with out over driving the amp, but by just under loading it instead. To increase loading, load cap DECREASES in value..and numbers on the scale increase..... and vice versa. 

The SM5BSZ approach is old news.  I own 2 x FT-1000D's.  Local buddy (now SK) also had  a 1000-D.  The biggest issue is..... most have NO clue how to set up the various front panel level controls.  They can't read  the manual either.  They end up with a convoluted mess every time.
Below is the correct procedure on any 1000/ 1000D.

1)  with processor OFF, adjust mic gain for 2/3 to  3/4 ALC reading.

2) with processor on, AND multimeter now switched to read RF clipping level, adjust clipping level control for 10 db of clipping. Note, since none of the multimeter meter functions read peak, only average,  10 db of clipping is actually 20 db of clipping.  Most bozo's will crank it up to read 20 db of clipping, so it's actually 40 db of clipping.

3) switch multimeter BACK to ALC position.  Then adjust Drive control for desired ALC.  With processor on, the drive control is essentially a RF clipper output level control. Note, even with very little ALC showing, like 1/8", you will have max pep out..and bucketloads of talk power.

Typ what happens is this.  XXX see's that he doesn't have hardly any 'alc action' on his 1000-D.   So he reaches over..and cranks the mic gain up, till it's at max.  (He should have used the drive control).  IF he then switched the multimeter to read clipping level, he would see that the clipping level is now into the stratosphere.... but they never do.

They can't fathom the concept that the mic gain control is an ALC INPUT control.  The drive control (only when processor is on) is the ALC  OUTPUT control.   Crank the mic gain up, instead of the clipping level control, and the clipping level will INCREASE.    If no external audio compression is used on any ham xcvr's, the processing level is then a function of how loud you talk into the mic.  You are then stuck with either trying to talk at a constant level, or use a boom-headset, where at least the mic is always a constant distance from your mouth.

They can't understand the basic concept of how  RF clipping actually works.  They can't read a manual either.  The wattmeter in the 1000/1000-D does not read PEP.  The wattmeter is not calibrated either.  When I bought my 1st  1000D, brand new, everything in it was out of calibration..and I mean everything.  They all come with a quickie calibration..that's in the ballpark... but not dead on.    Calibrate the entire xcvr..and u now have a functioning xcvr...that actually works.

On both my new MK-V's, the audio level to drive the (peak reading)  alc bargraph  to max,  was 4 db down from what's in the calibration manual. Between just a tiny bit of alc showing..and max, should be exactly 10 db.  Mine was 6.6 db.   I left it alone.   If adjusted to  10 db, then joe ham would just max it out anyway, regardless of calibration. ( calibration done using an audio tone).

Unless you are lab testing at least 4-6 of one model of xcvr, I would take the results with a huge grain of salt.  On the 1000-D there is only ONE bias  control for idle current.   On the MK-V, there is  EIGHT bias controls to adjust. 4 for Class A..and  4 more for Class  AB.  ( 2 of the P-P driver transistor's,  one per transistor)...and  2 for the final PA  P-P transistors, again 1 per transistor.   Get any of the 8 x bias controls outa whack, ur gonna have erroneous results with any IMD testing. 

I uses  ESSB, so a huge chunk of the processing is done external to the xcvr.  I use a downward expander instead of a noise gate... moot point.  (a noise gate is just a high ratio downward expander, literally operates like a light switch).  Done correctly, scream or whisper, I get a constant, clean level  going into the rest of the external audio gear... including the final  box, which is a  split band limiter / distortion cancelled clipper...( output adjustable in .2 db increments)..that mess goes through a 20 db pad..then into the   analog Balance modulator in the MK-V. ( I bypass the junk oem mic pre-amp in the MK-V).  Calibrate the xcvr, then it's all good.

On newer xcvr's, some of the audio processing is done in the xcvr, in the digital domain.  Overshoots are easy to fix on xcvr's that have overshoot issues..... using fixed external ALC voltage fed to the ALC jack on the back of the xcvr, problem solved.

[KA4WJA]

Jim,
As I've written over the years, I've always liked the MkV.
Thanks for all the additional info...especially the details on the MkV (versus the '1000D)!

Guess this reinforces the fact that we (amateur radio operators) really do need to understand the radios (and amps) that we own/use (like you understand yours, and I understand mine), and understand what various parts of our systems do (whether it be processing, ALC, various bias levels for different "class" of amplifier, mic gains, etc.)....after all we are self-governing and it is up to us to maintain our spectral purity! 

So, your words (albeit might only be read by a few) do help our amateur radio community.



Won't drift this further....so, just an fyi...not sure how many of the new '101d/MP's (and '10's) you hear on-the-air, but down here (in Florida, > 2500 miles from you) they are becoming pretty popular on 80m SSB, and we're getting lots of buckshot from them. 



Thanks again.
73,
John,  KA4WJA

[VE7RF]

Jim,
As I've written over the years, I've always liked the MkV.
Thanks for all the additional info...especially the details on the MkV (versus the '1000D)!

Guess this reinforces the fact that we (amateur radio operators) really do need to understand the radios (and amps) that we own/use (like you understand yours, and I understand mine), and understand what various parts of our systems do (whether it be processing, ALC, various bias levels for different "class" of amplifier, mic gains, etc.)....after all we are self-governing and it is up to us to maintain our spectral purity! 

So, your words (albeit might only be read by a few) do help our amateur radio community.



Won't drift this further....so, just an fyi...not sure how many of the new '101d/MP's (and '10's) you hear on-the-air, but down here (in Florida, > 2500 miles from you) they are becoming pretty popular on 80m SSB, and we're getting lots of buckshot from them. 



Thanks again.
73,
John,  KA4WJA

Here's the main problem with the MK-V...in class A.....  it will overheat in just a few mins of use !   There is NO airflow going down heat sinks 1+2.   In class A, it idles at 10 amps  @ 30 vdc=  300 watts !!....(=1023 BTU's)    One guy I know, fried 2 x sets of transistors  before he would listen to me.   $675.00  repair bill from yaesu the 2nd time.    In Class A, it runs hotter on idle, then when driven to 75 watts out.  Other than brief tests, it's useless, more of a novelty..and good for Class AB / Class A comparisons... that's it. 

What should work, is to tweak the bias, so it sucks less than  5 amps per transistor, but more than 1 amp per transistor.  Somewhere between those 2 x extremes is probably a more than acceptable IMD level..and still not cause meltdown.   Class A is way over the top.  Notice in the ARRL extended lab write up, they switch the spectrum analyzer from 80db...down to 100db..when doing Class A  IMD tests.   The driver transistors could also be tweaked, or remain in Class A.   I don't think they have a heat issue.  I have not tried the re-biasing scheme...yet.   This should be a good experiment. I see no point in the xcvr having IMD that far exceeds the amp it's driving.

The newer yaesu's idle at 10 amps...but at 50 vdc = 500 watts =  1705 BTU's.   I believe the newer yaesu's have front panel adjustable bias.   The MK-V has 8 x internal pots to tweak..and is a major pita, to get in their with a fluke 87..and measure current levels between test points. (yaesu provides slide switches across the test points )