I know that the antenna is what really gets things done and investing in a better/higher/whatever antenna offers tremendous rewards. However, I am not doing that at the current QTH because I will be moving next year, if all goes well.

What I am going to is get an amp. It will serve me well now and in the future when I reach my retirement QTH and can put up some sort of better antenna.

Have been on the Mercury III (1200w) waiting list for a while. Some day, they will ask for the deposit and put mine together. HOWEVER, now they have announced a second amp option (for $1300 more), The Mercury Lux - a 1500W amp.



People on the waiting list will be given a choice of either amp!

What do you guys think I should do, when offered that choice? Buy once, cry once? Or would 1200w be all I could ever need?

Think it through. Do you need the remote control abilities that the new amp offers?  The 1 db of gain you would gain power wise isn't much. Certainly not enough to be heard on the other end. The "overhead" capability of having two LDMOS devices instead of one in the Mercury IIIs is likely a good thing. But is the juice worth the squeeze?  It all depends on you.  For me, I am perfectly happy with the Mercury IIIs. The Mercury IIIs is pretty.  The new LUX is really pretty.  :)  In my opinion, either one is going to be a great choice. My Mercury IIIs is coming up on 2 years of great service, used nearly every day. It is a joy to look at its beautiful display every time I turn it on.

There is no real difference in signal between 1200 watts and 1500 watts.

It’s like saying 120 watts and 150 watts, except it is even less of a difference.

The real issue to me would be duty cycle. If you are running 1kw and can do it forever with the 1500 watt amp and have short limits on the 1200 watt amp, that would be a deal breaker for me.

Going to go look up the details

Emoto,

I don’t have anymore time in the hobby than most of the new fellows here so take it with a grain of salt.  I often hear that things open up for hams around 500 watts.  

I keep getting reports on our net that I am 59+10 often enough, not all the time of course.  I am only pushing 400-500 watts on a 30 year old Ameritron 811H that claims 800w capability.  

I think you’ll be very content with 1200 watts and likely have no need to run it at that capacity.  

That said, if spending the extra coin isn’t a problem it’s nice to know if you are on the edge of making that far dx contact that dialing it up some more may get you heard.  That also begs the reminder that if you cannot hear them, you cannot work them.

I am getting much better in tuning my 811H than I was six months ago.  I still wouldn’t mind full auto to avoid the operator errors.

Exactly.  The first 600 W is the most important.   Maximize those with a well matched antenna can easily get you contacts around the world.

I run the same amp 811H between 500-600W and if conditions are good I have no issues.   1200-1500w is gravy, delicious gravy.

With that said, I've been interested in these LDMOS amps for a bit.

Im happy with my 500w but always thinking of upgrades anyways. The 3s can run on 120v. I dont have an easy way to get 240v to the shack area. Does the 1500w amp require 240v?

Sound like 50% more $$ for not much more power. Meh.

Kind of disappointed, limited to 800 watts digital modes and only a 1 minute transmit time.

You would think with the dual LDMOS Transistors, there would be no limit like that.

I suspect it is a power supply limitation due to the small internal power supply.

Can also run on 120v with a 20 amp circuit.

https://www.km3km.com/wp-content/uploads/2022/08/Operation-Manual-v1.5-LUX.pdf

Nice. On page 4 it says 1200w available on 120v but for 1500 you need to have 240.

I had a 240v outlet put in my shack some time ago in anticipation of the IIIs. It is also the room where the main panel is, which simplified matters somewhat.

If remote control is never going to be an issue for you then IMHO the juice is not worth the squeeze. The IIIS is a wonderful amp, and I'd own it in a heartbeat if it were not for its lack of remote control capability. It's pretty shocking that nobody has yet hacked/mod'ed the Arduino controller code in the IIIS to add remote op's.

On the other hand, the LUX compares very favorable price-wise with it's nominal competition: the KPA1500, Expert SPE series, and probably a couple of other fully optioned, solid-state amp choices I'm surely overlooking. Consider that the KPA1500 is $6700, and the Expert 1.5K is $5500. However both of those amp's have ATUs whereas it would appear the LUX does not. So there's a big difference. If you don't need the tuner you are saving between $1200 and $2400. Or you could buy a great external tuner for a lot less.

I already have an external tuner that is 1500w capable, so am good there, either way.

Yep, that is a nice tuner, I have it too and it works great with my ALS-1306. I just wish it had better sensitivity at low power for a better solution. It really needs to settings on what SWR it will settle for. Something like 1.1 for 6 watts and 1.5 for much higher power. The push to tune with the IC-7300 consistently gets 1.0 on the 6 watts tune power then at high power it is 1.8 or 1.9.  I fix that by turning amp to standby, using 40 watts ( 1000 watt setting with amp in operate ) and pushing tune and get below 1.4 but that extra step is a pain. I can’t believe I am complaining about this because it is minor especially compared to a manual tuner )

The memory does work for going back to the better match though.

Not sure I follow. Are you talking about setting a Target SWR like on pg 19 here? https://cdn.shopify.com/s/files/1/0289/7782/3843/files/MFJ-998.pdf?v=1586534121

When I hit the tune button on the IC-7300,
(6 watts tune carrier ) I get a 1.0 SWR.

Then when I transmit several hundred / 1000 watts I get an SWR of 1.8-1.9 ( sometimes more than 2.0 and I get a fault in the amp ) even though I have a displayed match of 1.0 SWR at the tune power from the radio of 6 watts.

I have to transmit a manual key down of 30-60 watts and hit the tune button on the tuner to get a better SWR so that when I transmit high power the SWR is 1.4 or below.

It seems at the IC-7300 tune power of 6 watts, the reflected power circuit in the tuner  is just not sensitive enough to get an accurate match at low power that translates to a good SWR at high power.

I see no way to increase the IC-7300 tune power above 6 watts to say 30 watts. I think that would fix the issue.

Maybe I am doing something wrong?

I don't see a way to increase that power, either.  Does it help to have the radio in RTTY mode?

Nothing is going to help, and you are not doing anything wrong. It is just the way it is. SWR bridges are not very accurate at low power levels, and they ALWAYS under report as compared to running at High power. I have observed this for years.

Nothing wrong with what you are doing. It's a limitation of the MFJ QRO auto-tuner design. It just needs more power to get a more accurate result.

If it bothers you that much you could write some software that controls the radio for you and that would help automate the high power tuning process. I did this with my MFJ998RT remote tuner. I have software that, at the push of a button, puts the radio in the right mode and high power tune state, then reverts it back to previous state upon a second push of a button. I also have an alternate mode that cycles DC power on the tuner first so I get a fresh tune instead of a memory tune. The only thing it does not do is automatically complete the tune cycle since the RT version of the tuner can't provide any tune-complete signal, so I just wait until I see the SWR settle then hit the button again.

I don’t think so, any carrier will work to tune. The IC-7300 when tune button is pressed puts out a 6.7 watts carrier.

That is what I suspected.

It is a minor inconvenience compared to a manual tuner. The IC-7300 is not an open source firmware, not that I could write the code, but my son probably could, he reverse engineers radio firmware for fun and writes his own.

I have gotten into the default programming setup  of the IC-7300( forget what it is called ) but am reluctant to try to change the tuner carrier level in fear of screwing it up. It also needs a calibrated signal input that I don’t have.

I tune in steps.

I get the auto antenna tuner first by tuning 10 plus watts from the radio usually on rtty.  Then up to 20 watts to see if there is a touch up.
Then I verify my amp settings are from my data card are set.  
Flip on the amp and tune the amp settings as needed.  

I have got a lot better at this.  I used to think my amp wouldn’t reliably tune 20m or above frequencies reliably.  I thought I had an amp issue.  It turns out I had an operator issue and my settings weren’t spot on and it wouldn’t tune, power would drop out on the amp immediately.  

My amp is better than I thought it was once I got more experience.   Life is simpler now that I only manually tune the amp and not still using the older TenTec manual tuner.  I got mixed results tuning with the TenTec, their instructions say there is only one best setting.  I did not find that to be the case and was suspicious of my tuning with it.   I did fix one problem, I had a loose capacitor knob, the set screw on the shaft was loose and would slip so going off my notes was inaccurate.  I lost faith in the thing.

You misunderstand: the software I wrote controls the radio via CAT commands. No messing about with internal firmware is necessary.

I don't know if you use a PC in daily operation, but if you do, based on what you and I have chatted about previously, your son could probably whip up what you need as a small app in an hour or two.

Oh that makes sense, I bet he could, he automates all kinds of things

After over 7 months of being on the list, I am finally up to the next stage, which is to give them a deposit and they will start putting together an amp for me.

No kits are available at this time, so it was a choice between the 1500w and the 1200w amps, fully assembled and tested.

I decided to go big and selected the 1500w one. Knowing myself, and even bearing in mind all of the informative posts here about how little difference that really makes, I know I won't ever regret having a 1500w amp, but if I got the 1200w one, I would have that little nagging voice of doubt in the back of my mind wondering if I could have made that failed QSO if only I'd had a few more watts.

Now, it is theoretically an 8-10 week wait while they build and test. Balance due just prior to shipment.

I am VERY excited about this!!!

And now, I turn my thoughts to making sure I understand how to hook up the damn thing correctly because I do NOT want to let the smoke out of any of the boxes. My antenna and Tuner are allegedly rated for 1500w.

Currently, I have: IC-7300 > MFJ 998 Tuner > Antenna
There is an Icon-specific interface cord that runs from the 7300 to the tuner so that I can tune with the 998 by means of a push of the radio's tuner button. This works well.

I think the way it is supposed to go is:

IC-7300 > Amplifier > MFJ 998 Tuner > Antenna

As I peruse the manuals for my 7300, the LUX amp, and the 998 Tuner, I am wondering if what I am seeing is simply different terms being used for the same items, or if there is a larger difference.

I would appreciate any comments or guidance about connecting these things properly.

1. I am thinking that the "SEND jack" (in green box on icom diagram) goes to the "Amp Enable In" jack on the tuner, and the the Tuner's "Amp Enable Out" goes to the Amp "RCA PTT plug" (#9 on Mercury back).  Does that seem to make sense?

Another thing not clear is that I currently run an MFJ-5114 interface cable from the Radio to the Tuner. The Amp seems to want me to run a Band Data cable from the Radio to the Amp. Where that plugs in on the Amp is #1 on the Amp, and the only connector that matches on the Radio is in the red box on the image below. Does that seem right to you guys?

IC-7300
Here is the icom manual showing the back panel and what it says to connect to a (non-icom amp) amp:


TUNER
Here is the a diagram from the Tuner manual:

Back panel of Tuner:


Mercury Amp
Here is the back of the Mercury Amp, followed by the Band Data cable info:

Note 4 & 5 out of order





Reference (full manuals):
Mercury Amp
MFJ Tuner
IC-7300 Manual

Well, I don't own that amp and I don't own that tuner, BUT it would see to me that yes the coax connections of course would be :

7300>Amp>Tuner> Antenna.  

Now as for the key line yes the send port on the 7300 and RCA plug on the back goes to the tuner in inhibit and from the tuner out to the amp.
The idea being that when you send a low RF level from the rig the tuner will prevent the amp from keying up. And the tuner will not release the keying line
going to the amp until it is finished tuning up at a low power level. Then when the tuner is finished it releases the key line to go from rig to tuner in and straight thru to tuner out and into the amps key line. The relay in the amp will now key up and the RF will go into the amps input and excite it to make high power out that goes into the tuners coax input and finally out the tuners coax power output and head toward the antenna.

Now to the band data. Band data can come both from the 13 pin plug on the back of the 7300 AND it also can come across the 4 pin white molex plug on the back of the 7300. I believe there is a menu item to have band data come out the Molex 4 pin also. You didn't post a picture of the MFJ rig cable but if it is 4 pin Molex to the what looks like an RJ45 jack on the MFJ tuner then I would hook it up also.  Obviously the Mercury Icom cable you bought goes from the 13 pin accessory plug on the back of the 7300 to the 9 pin D connector on the Mercury Lux.

So yes, I looked up the MFJ 5114i cable and it looks like a 4 pin Molex to RJ45 cable.  So yes that goes from the Icom 7300 4 pin Molex to the tuners RJ45 interface.   So now why you change bands on the rig BOTH the tuner and amp should change to the correct band, AND when you press the tune button on the 7300 (provided you set the menu settings to do this) the rig provides less than 10 watts of power thru the amps coax connections, the amp DOES NOT key because the tuner has inhibited the key line from the rig, the tuner tunes up if necessary, OR it remembers the band and does not go thru a tuner cycle. Likely the upper bands may not need a tuner cycle, but the lower bands like 80 would have to have a lot of tuner memories because it is so wide. so with the tuner tuned up, then the tune cycle drops out, and the key line is no longer inhibited and is made thru the tuner to the amp, and you apply drive power and the amp keys and amplifies.

Let us know if it doesn't work like that.

If it doesn't, I will have always thought it should have.

@Emoto

First of all, good on ya' man for cracking the manuals Next thing you know you'll be picking up a soldering iron. Gosh darn it, you might be a real ham!

All good on the tuner, PTT and RF connections. However the cable for band data connections looks wrong.

As you know from the manuals and the excerpts you posted, band data appears as a voltage on pin 5 of the 7300 ACC connector. Per Mercury's own manual, page 13, this should go pin 5 of the Mercury Band Data connector. This would mean that the cable shown on page 14 of the Mercury manual is wrong.

You might want to correspond with Mercury about that.

One thing you have not mentioned are ALC connections. I'm kind of spoiled in that I have a radio that does not require an ALC connection so I am unpracticed in the art of ALC adjustment, but it's something to consider. Even Mercury recommends not using it if possible, and it should be possible to avoid it by properly controlling the radio RF power drive level into the amp. But perhaps others might chime in.

I use the 7300 with the same tuner, but have an ALS-1306.

The radio is connected to the amp with a special cable that controls ALC, band data, and putting the amp on standby when the tune button on the radio or the tuner is pressed for as long as the radio is transmitting the tube signal, then it reverts back to operate.

There is also a connection from the amp to the tuner and back to the amp. That connection passes the information on the tune signal from the amp to the tuner that originals either from the radio or directly from the tuner. The tuner does not know band or freq until you transmit or press either tune button, and when either of those happen, it takes the freq from the RF, and sets a memory setting or if it doesn’t have a memory setting, it finds a new solution.

So the cable from the 7300 to the amp is a special amp cable for the IC-7300. The cables from the amp to the tuner and back to the amp are 2 RCA cables.

The only other cable is the cable from the tuner ( 4 pin in a straight line ) from the 7300 to the tuner that allows the tune button on the radio to activate the tune button on the radio to bypass the internal tuner and activate the tuner. I think it might also send band info to the tuner, but on,y when the tune button is pressed. It doesn’t send band info just changing bands without transmitting like it does to the amp.

The ALC is built into the radio amp interface cable so is the PTT.

The Amp enable out RCA goes to the Relay on the amp.
The loop and relay I think are MFJ specific and I think that is what keeps the amp from PTT when the tune button is pressed, but I don’t think the Mercury has this


Hopefully I didn’t cause confusion in this explanation, but I probably did because now I am confused.

Good stuff! Thank you for all of that; it really improves my understanding! I will need to run through all of the relevant 7300 menus to make sure things are enabled. That is an excellent point.

I am a "read the manual" kinda guy. Especially when something expensive is involved.

Excellent catch on the pin # of the cord. I will write to them about that as well as the back panel item numbering error.

Yes, there is an ALC connection. The 7300's output jack and the Amp's input jack are clearly marked without any ambiguity due to differing terms, so I didn't ask about that. The Amp manual has a section in it on how to adjust the ALC on the amp side while hooked up to the radio. I do intend to properly control the radio's output so it is not clear to me what would drive the decision to connect and adjust the ALC. Maybe that is something obvious to more experienced hams?

Good stuff. Similar in some ways and a little different in detail. Thanks.

I am not using the ALC on my Mercury IIIs and here is why.

I want to run different amounts of drive from the radio to the amp. As on digital modes, you cannot run more than 700 watts, that is one drive setting. BUT I want to run 1100 or even hit 1200 on peaks of SSB, that is another drive setting, and CW maybe run 1000, again another drive setting.  So how does setting an ALC pot on the back of the amp going to help me.? If I set it for the "under 700" setting then when you want to run more on SSB then I don't see how that can work.

I think it is better to just pay attention and watch your drive level for each band and adjust it according to what you want.  After all it is on a knob and is fairly repeatable. Yes the rigs do drift around a bit when they warm up and don't put out exactly the same amount of power for each knob setting of percent. But again, you do have eyes and can watch it. Also the amp will drift downward in power after it gets hot too. But all of this is no big deal. and the controller will go into fault instantly if you go over the 700 watt limit for over 7 seconds, and yes I have tested that several times. I think it might be 800 for the LUX. Ironically on FT4 you can get away with more power because the actual transmit time is 6.75 seconds. So you can ignore the digital power limit, and yes I have tested that, but it is not a good idea.

So there are my thoughts. YMMV.

What K0UA said

And, also...if you want to get really OCD about optimizing drive levels:

For single tone digi modes like CW, RTTY, FT8, etc., where only a single tone is transmitted at a time, key up in CW or RTTY mode and what you see is what you get. Drive to X watts on the amp output and you will always get X watts, no more, no less (leaving aside amp heating and other subtleties).

For multi-tone digi modes (like Olivia) or phone (SSB), where there are multiple tones transmitted simultaneously, use a two-tone audio test signal when adjusting drive. This creates a 6dB peak-to-average-power (PAPR) condition which is a very good approximation of these conditions.

For best IMD performance do not allow mic or audio drive levels to cause any ALC indication on the radio at all. With the amp you should not have to drive the radio hard, let the amp do the work. Set your mic or audio drive level to just below the level that causes ALC indications on the radio, then turn up radio drive until you get the amp output level you want.

Finally, don't be Billy Bob. Billy Bob paid for a 1500W amplifier and, durn gummit, he wants to see that baby pinned at 1500W all the time. When you do that with the typical average or, at best, "slow" peak reading power meters built into these amp's all the peaks you don't see are absolutely hammering that amp into saturation and you are creating some horrible "splatter". So when you used the super-cool, OCD two-tone method I suggested above to set drive, and then speak into the mic, it's going to seem like you are barely peaking 1KW. But those 1500W peaks are there. You can only see them using an oscilloscope or a true, "fast", peak-reading power meter.

Bottom line, it is normally not good to drive anything "balls to the wall".  If you back off a bit, you will have a cleaner signal, I believe the amp will last longer.

Pretty sure emoto is not into digital.

This seems like a reasonable approach. On the 7300 it is extremely easy to adjust output, and once I note how many watts the amp wants to see from the radio, I don't see why I shouldn't be able to stay under that. I only do phone; no FT4, FT8 or any other digital mode. So far, I've only used SSB for QSOs, but may play around with AM and FM at some point and will want to make sure the output is still within what the amp wants to see. (I suspect it will be, but I am cautious.)



I typically don't run my vehicles at redline, because even though redline is "ok" I like to be gentle in how I use things. Oh sure, maybe every once in a while, but not often. This behavior carries over to my station. I like keeping my things for a long time without breaking them.

How does one generate "a good two-tone audio test signal" and introduce it into the system during adjustment?  

Interesting point about meters not showing the peaks. That's not great and kind of alarming.

To clarify what you say about setting the ALC, below is how ALC is represented on the 7300 (not my image, but I did add the arrow). When one speaks into the mic, a blue bar extends from left to right, and covers the hash marks just above the horizontal red line. If your blue bar extends to the right of my green arrow, i.e., past the right end of the red line, the ALC sharply reduces your output.

Are you saying to not go beyond the end of the red, or to not even show up on the red at all? If the latter, would that hamper making QSOs without using the amp?





Good advice, and fits in with my natural inclinations.

About ALC on the IC-7300

No more than about 80% to the end of the red line is about the max you want to be. You adjust that with mic gain and compression. If you get to the end of the red line you will get distortion of the audio signal. Getting to 75-80% is good because you bring up the volume of the modulation and will be louder on the receiving end for the same power output.

At least that is what I have read, I avoid listening to myself because I am boring as hell, and the few times I tried I fell asleep.

And why the hell do you not do digital , God gave us digital modes for a reason. I don’t know what the reason is but there must be one.

I'd start with merely playing one into your microphone. I don't know if you are an Android or iOS guy, but I'm an Android guy and can recommend this dual channel function generator app: https://play.google.com/store/apps/details?id=com.keuwl.functiongenerator&hl=en_US&gl=US

The de facto standard tones are 700 and 1900Hz because they are in the passband and not harmonically related.

Once you get everything sorted out and have reached your first happy place, then you can do things like wire signal generators directly into the radio through the ACC connector or USB connection.

In the meantime I have a radio that has the two-tone function built-in

Yeah, this is why all adjustments should be done to the extent possible with steady state signals. This is why that two-tone test is so useful.

And you need to be cautious even with high end equipment. For example, even the vaunted LP-100 wattmeter will read peaks lower then they really are. The only good way to truly see peaks is with an oscilloscope set up as a station monitor. But since there are other ways to adjust things (two-tone, etc.), if you trust the math and don't get emotional about the meter on the amp only going to 1000W when you speak all will be well. Or you can buy the 'scope and an RF sampler

I don't have a 7300. I would have said "Go as close to the end of the red line as you can without going over." However, again, that's probably not a good peak reading meter. So Mach's advice to keep it down to about 80% makes a lot of sense, as there will be plenty of peaks above that you can't see on the meter.

Ok, I think I have my ALC (sans amp) adjusted reasonably well. I have had some on air help from some fussy and helpful guys.



Because I spent many years toiling in IT in various roles, some of which meant I wrote or tweaked code of varying descriptions, or did network testing, etc., and digital modes remind me of that. It took a looooooong time for me to find a decent gig that was not IT and I have no intention of going back in any way, shape, or form. I know digital modes are NOT that, but they look enough like it that I want absolutely nothing to do with them.

Ah, "there's an app for that". I'm an android guy, too. I will look at that one.

I probably won't go the oscilloscope or other lab grade testing equipment route.

My Mercury amp is in QC and should ship within a few weeks.

Prepare for a life changing event. You will soon see why life is too short for 100W

Nice!

I figure I may hear from them in the spring.

No more Emoto is at murmur level tonight!

You probably need to buy a bunch of chokes, you may need to choke lots of stuff in the house if your antenna is not far from your house.

I am looking forward to seeing how it all works out. Very excited about getting a major piece of equipment for this new hobby of mine!



Well, you never know. There seems to be some kind of cosmic barrier between our locations.



I am not opposed to that, but why would having more transmit power bring about that need?

It's a legit concern. When I went from 100 to 500W there were some RFI problems in the house. When I went from 500W to 1500W one more showed up.

All of these were external to the station. Eventually, through a combination of grounding and bonding and the use of ferrite snap-on chokes at the feed points and at the amp output, I'm down to just one problem child, which is that my landline phone will ring when I transmit in certain parts of the 160M band at 1500W. I feel confident I can fix that by further adjustment of the length of my inverted L.

In other words, if you've got any issues then going to 500W may find them pretty quick.

Survey says the problems you have fixed at 500 watts manifest a whole new set of problems at 1200. You get to redo old problems with more Mix 31 ferrite, and you add some new problems you didn't have at 500 or 600. At least that was my experience, but solve them I did, and went on to enjoy my Mercury IIIs. Love it.

With Mogwai come much responsibility. Amplifier is just another version of a Mogwai.  Just don't feed them after Midnight.  :)

At 800+ watts I

turn off and on my wifes air cleaner
activate the smoke detectors
fried an ethernet switch
turned off some LED light bulbs

my antennas are right next to / over the house

My vertical is about 150' from the house. Everything is properly grounded, and I have current baluns
at the antenna and at the point the coax enters the house. I put ferrite chokes on the important stuff
as well.

I can't run past about 200W without having issues. I thought it was due to ground currents, etc, but
did the math on my radiated field and right around 200-250W is when it's over 3V/meter in the house,
right about where logic levels are and right when I start having goofy issues. There's a lot to be said
for a large horizontal/vertical separation between the antenna and the operating position.

So, in a nutshell, the issue is that transmitting above X number of watts of RF power may cause various household items to do things?

My antenna is about 65' away from the house and is a little more than 60' AGL, if that matters.