I suspect its the grid bias and grid current monitoring system in the Emtron amplifiers that is the real cause of the problem. There is no reliable indicator of grid current on these amps. When these amps splatter they must be drawing grid current that is  only detected when there is an excessive amount of grid current.  I have monitored a DX2SP into a dummy load using a real time spectrum analyzer. The resulting  splatter in real time is like square wave on either side of the signal as you get the peak splatter. If this was a normal normal metered homebrew amplifier you would see this fault immediately  on the grid I meter.

If you do a real dynamic IMD test  using a voice signal you will hear this leading edge splatter burst thats indicative of  grid current draw.    What other conclusion can you come to when  its a given that drawing grid current on SSB will cause splatter. While  I have done 2 tone measurements on one of these amplifiers and the resulting 2 tone numbers are respectable, the dynamic on air  performance is terrible.  Who do you blame the amplifier manufacturer or the radio, manufacturer?

All my homebrew  Tetrode amplifiers have always a sensitive op-amp driven grid current I meter.  Any hint of grid current flowing could be detected. How do you do this on a tetrode control  that uses a  LED display with coarse poor current monitoring hysteresis and one one that has no active grid current display?

In the hands of the average ham these poorly designed tetrode amplifiers are  nuisance on the bands. Try tuning the websdr.org SDR receivers in Europe and listen on 40 and 20 meters you can easily spot these tetrode amplifiers they that obvious on the waterfall display.  Its very rare to hear  splattering triode amplifiers, its always a joker with tetrode amp that causes the damage. When something as simple  a single LED grid current indicator could help these operators tune these amps, one has to wonder why they leave such critical monitoring  off the front panel and only give an alarm when there is really excessive current drawn. Its then no surprise that just about every commercial tetrode amplifiers causes excessive splatter.


 

Do they reallly do that? A friend of mine has several of them. I always wondered how well designed any tetrode amp really is.

Overshoot or dynamic regulation problems do not show in a two-tone test. Which do you think it  has?
[/quote]

Why would anyone want to use a splattering CB amplifier on the ham bands?

These old sweep tube CB amplifiers belong in the garbage can and not on 10 meters.

The fix for this is to use  or buy a filter with a earth line choke. Just do a search for earth line  choke filters. You can take a  norm  mains filter and just wind the earth wre through a #43 toroid.
Earth line choke filters are considered to be best practice these days for EMC suppression.

You have to very careful  because the USA and UK mains systems are very different. You have to very careful about adopting there wiring practices in the USA and vice versa. If you dont know these difference you are best
advised to buy a standard EMC filter with earth line choke in it designed for the USA. Homebrew filters can be very dangerous if you size the capacitors wrongly or use the wrong kind of practice. These filters are so cheap there is no need to risk your life trying to be cheap.

They also have not worked out how to package the Brewster angle into a packet  yet. Many hams seem to think that vertical work the same regardless of where we place them in the world.

You hear a 1 or 2 stations on the bands with these magic 43 ft verticals.   These stations are all living in areas with high ground conductivity. You never hear anyone from the dessert in Arizona boasting about his magic 43 ft vertical.

The problem with traps is that nobody makes high power versions of them that can truly take legal limit. To make a trap that will handle 2500 watts is expensive and challenging.

I dont know why people mess with these cumbersome vertical designs when something like a simple parallel   multiband  vertical antenna system works without all the fuss. You can build a 40 through to 10 meter multiband vertical just by paralleling the verticals like a fan dipole.  You can then put a trap on the 40 meter vertical for an inverted L for 80 or 160.

Many hams have also forgotten about the Battle Creek vertical. My version uses parallel verticals for the higher bands and coaxial traps for the low bands. Cheap and very effictive.  No UNUNS, Baluns or complicated tuners or switchboxes.  All these designs are floating around on the net for free. K9AY also has a patent and a design for a multiband parallel vertical that is very unique. Any ham could duplicate this design with ease. No traps or anything complicated, as easy as building and tuning a dipole.

You making life difficult following the attenuator path. This would be a good idea for those Aussie Emtron amplifiers that produce a lot of splatter from ALC and power overshoot.

A simpler method would be to just apply negative  voltage to the ALC connector. You can use a 9v battery and a variable resistor and vary the  ALC voltage. This method produces absolute power control.

This is a good trick for  tube radios like the TS830S  and others. You cant vary the power on these radios since they have no power control. A variable ALC voltage gives you a precise power control.

Here is a link for how about going about it. Make sure you use a decent oscilloscope for a peak reading wattmeter. Most wattmeters that hams use are useless peak reading wattmeters.

http://www.astromag.co.uk/ft857d/

Where do we start?

The operators will always try and blame your receiver and then try and tell you that you have your noise blanker on.  This tired old excuse does not cut it these days. Most operators are aware that you cant use a noise when the band is full of strong signals. These days most receivers have sufficient dynamic where it really is impossible to  crunch the front end. This is not the year 1970!

IMD that is 20 db  down is pretty common these days.   We can blame the manufacturers for these badly designed transmitters. The bands are so bad these days with IMD that its routine to hear splatter from DX stations. Now imagine
how bad the IMD suppression really is if  the IMD  is actually loud enough to travel across the world! You  want to experience this try listening to the many web SDR receivers in places like Europe you will be really shocked how bad the splatter is these days The SDR waterfall is worth 100000 words!  Its not only from Europe its from right across the world.

The chief reasons for being in the splatter club are these:

ESSB, 99.99% of people using outboard audio processing gear with excessive bandwidth cause a lot splatter. ESSB is a menace practice on the ham bands.

The use of CB amplifiers especially on 10 meters by ex good buddies. These stations stand out like a sore thumb and routinely take out 15 to 20khz of the band.

Russian Tetrode amplifiers. These amplifiers are just about the worst amplifier a beginner can use in ham radio. For a start,  they are  very sensitive to over driving and things like ALC overshoot. You
hear this kind tetrode  over shoot splatter on just about every ham that uses these russian tube amplifiers. Its a combination of the poor tube IMD and the transceiver ALC/power spike issue. Most of these amplifiers
could be modified to high drive rather than low drive which could help the splatter problem. For this reason  I would never recommend a Russian Tetrode amplifier to anyone who wants  a clean signal with any modern ham transceiver
which most has poor IMD performance and ALC overshoot problems.

Then we have the LIDS, these guys are just bad operators who are smart asses and dont give a damn about anybody. They know what they are doing and splatter deliberately by cranking all the knobs to the right.

We then must move onto the hams with technical deficit disorder. These are the ones who typically work DX from a mobile or use a poor a antenna. You will hear a DX station say  that their  signal is weak can and can you repeat your callsign. The said idiot operator will say hold on I will turn my  MIC gain up a bit. They do this and you see 15khz of the band getting chewed up. This idiotic practice is  routine with poor antenna DX'ers and mobile operators. I wonder how cranking up the audio gain on ham transceiver actually increases output power? Maybe someone can sit down and explain why its wrong doing this to these ignorant  hams.

Its really time for the occupied bandwidth regulations throughout the world for ham transceivers. This will be a good first step in the right direction. Like everything else in life you cant make rules for idiots.
Ham radio used to be great when it was a true technical community where people took technical criticism on the chin. These days telling someone that they splattering is like calling their wives ugly. Its even worst when these
technical ignorant hams think that spending 10 thousand dollars on radio guarantees them a splatter free signal. I have a few operators tell me this I have this expensive brand X radio, its does not splatter. How can you combat
such a pathetic and technically ignorant operators?

If someone tells you that you are splattering all that you should request, is at what signal strength you are on their receiver and what their receiver brand is. You really should just terminate your QSO and tell the operator you will investigate the   problem . You should then connect the dummy load and second receiver and check you signal, its as simple as that. Launching a personal attack on the  ham  that reported that you are splattering is not necessary.
The louder the station protests and carries on about your bad receiver the more technical incompetent that station is, its really that simple. It takes all but 1 minute to check if you are really splattering. If you are using ESSB or a CB amplifier you probably are splattering! The number 1 rule is never ask your friend if you are splattering. This kind of sycophantic  ham buddy  backing his favorite on air ham buddy to make him look good is routine. You find the same ham buddies telling their friends that their audio is excellent even when they sound totally crap. Thats human behavior for you!

Its just such a pleasure listening to the many clean signals on the air. You hear these station running a humble pair of 3-500s and some good radio like a TS830S, TS930S  or TS940s or any other radio with good IMD.
Now it seems that every new radio and amplifier produces excessive crud. The fault really lies with the manufacturers that are producing junk most of the time. There are many other combinations of radio and amplifiers that produce
splatter free signals, they just getting harder and harder to find or buy!

At work we have tried every soldering iron in the business. The one with the longest  service life is the  Weller brand. The soldering irons at work are left on 24/7 and the Hakko and others  just lose their elements or  heating efficiency.  You always have to crank up the temperature every few months for compensation heat loss. This is despite a regular maintenance schedule.

In my humble opinion the Weller tips are the best in the business, they wet  very nicely and dont lose their ability to wet the tip with solder. Most other brands the tips need constant conditioning/tinning/heavy cleaning etc. The Weller tips clean nicely just on the wet sponge pad. The Metcals are nice if you can afford them. Tip wetting is very important if you do a lot of SMT re-work. If the tip cant take  wetting with a small amount of solder or paste it really makes your job hard. When you  do a lot of SMT re-work tip wetting is  one of the critical areas that  needs to be good. I also use  tip wet for removing SMT pin shorts using  the flick technique. If you tip wont wet or pick up small solder jobs you cant use these kind of quick re-work  tricks. Weller is my recommended brand.

Hopefully you dont have the ESSB idiots in VK. Its so ridiculous hearing  6khz wide ESSB idiots with  bassy audio trying to work DX with their selfish bandwidth practices. The DX window is so narrow and is expressly a DX window. Why these ESSB stations want to take out the DX window with excessive IMD/splatter and excessive occupied bandwidth is beyond belief.  If some of these ESSB stations operated in VK they could not really operate anywhere in the VK DX window because their signals are so wide.

I always use 1.5 X TX Audio bandwidth to be safe  that  allows for any IMD splash, you can never get into trouble doing this.  I use 2.4khz wide audio at all times  and my signal has very low IMD.

""
Now 80 Metre DX Window is a different kettle of fish in VK
3.776 - 3.800 DX Window SSB and CW.
NOTE: DX WINDOW
Emissions must not extend below 3776 kHz. Therefore when using LSB, the suppressed carrier frequency
should be no lower than 3779 kHz.

Also the Oceania DX Contest is being held on these dates,

PH - The first full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

CW - The second full weekend in October each year from 0800 UTC Saturday to 0800 UTC Sunday

Log deadline for PH and CW logs - 28 days after the end of the CW contest.
For more info go to the web page: http://www.oceaniadxcontest.com/

Regards
Eric

[/quote]

4cx350FJ  a superb linear tube designed for SSB service that is readily available.  2 tone 3rd order IMD figures of around -44 db at 200 watts of output

Use BLF175's they are excellent devices and have superb IMD performance even in class AB.

VRF148s would also be  a good choice as asuggested.

There many excellent devices available  however the manufacturers provide no IMD data which is rather poor marketing and engineering practice. What is even more astonishing is that  if you email the  engineering
departments they have no data and will make comments like "they are excellent but we have no data" Very unprofessional. When MACOM did not have any IMD data they would go measure the devices and fax you the data within
48 hours. Engineering standards are rather poor in the many takeover semiconductor companies around the world. A good case in point is Mitsubishi, they manufacture some nice RD series of fets however they have no IMD data,
pathetic really. What do their engineers do all day?

It will be interesting to see what the INBAND audio IMD of the KX3 is.

There is nothing better than a smooth sounding low IMD receiver. The TS870S was such a radio, very low distortion on RX.

Direct conversion receivers like the  R2 from  Rick Campbell  also excels at producing excellent RX audio.

Lets hope that the RX audio is better than the K3's!

Its fair to say that every radio splatters. Its by how much the splatter is suppressed by that  is the main concern.

The KX3 will be probably be ok at 10 watts of output because the potential for collateral damage is low because of the low power and poor antennas.

Why I am not impressed by 10 watt QRP radios and their IMD performance is that its inevitable that many operators will chose to  boost the signal with an external amplifier. 9 times out of 10 the choice is
a lousy crap box CB amp with poor IMD performance. There is this very  discussion on the Yahoo KX3 group now. People boasting about how good  a crap IMD performance RM Italy CB amp is when used
on a QRP radio. This is utter stupidity really by hams who are just following their  ex CB practices.

The point is that if the radio has poor IMD  performance and you combine it with a even worst IMD performance amp,  the total  combined IMD performance is worst than the best IMD performance from  either the radio or the AMP.
Its seems its going to be difficult to break the common QRP practice of using lousy amps with radios that have questionable IMD performance.

When radio is sold as   a 10 watt qrp radio its IMD performance is optimized for 10 watt QRP levels with low power. The radio wont have sufficient IMD performance for 1500 watt legal output level with big antennas. This essential
point many QRP enthusiasts forget about when stupidly connecting a CB amp to the output of their QRP radios.

Its early days for the KX3 we will have to wait for the ARRL review. The one aspect of the KX3's design that will be correct is that it will have a transmitter that does not produce ALC splatter. I am not optimistic about the IMD performance of a battery operated radio. The KX3 probably has  the potential to  use adaptive pre-distortion techniques that could give it the ultimate IMD performance. The design has a lot of potential.

A 10 watt QRP radio if it had sufficient IMD performance would make a nice  driver for a tube like the 4cx1500B. A 4cx1500b could deliver full legal output with less that 5 watts of drive. I would not do this with a radio that has marginal
IMD performance. This aspect of QRP radios utility is lost on the designers of QRP radio designers, they really squander the radios potential by producing a low power radio with poor IMD performance which could make excellent drivers for tetrode amplifiers.  It would be very easy to homebrew a 200 watt tube amp that only takes 1 watt of drive or less.

QST  did a terrible review of the Wavenode System. They mentioned the spectrum analyzer, but did not test its dynamic range or speed  to see if its fast enough  to act as a reliable splatter monitor.
The Wavenode web page does not give much reliable information on how good the system is. It would be nice if they placed a video on the page showing how fast it is.

Any SDR receiver is still the best spectrum analyzer that the average ham can afford. The better SDR receivers have spectrum analyzer performance that cannot be matched for price.

Any decent  second receiver is another good choice, I do this routinely. I just park a receiver 5khz away  while on the air. Its easy to hear any unusual IMD. This helped me to find a faulty balun which was hit by lighting, I could hear the fault before I even knew about it. The lightning damage balun caused horrendous TX imd problems that was evident on the second receiver.

The FCC can get one individual in court yet they cant stop the crazies on 14.275 and 14.313? These crackpots are doing  exactly what K1MAN was doing, why are they leaving these others alone?
It would be nice if the FCC had a proper cleanup of the ham bands and got rid of all the crackpots.

A dead horse subject that is very relevant. It  a  really subject that determines whether  you have the brains to understand technical matters and how it relates to the  real world performance of transceivers.
Now if you are too  stupid  and cant realize that spending a fortune on a radio with excessive receiver specifications and whose real  world performance is handicapped by  the poor performance of  other hams transmitters,, you  really need to beat your brain cells into gear rather than beating  the dead horse messenger.

Its the many hams who have flogged their favorite dead horse subjects  that has resulted in better ham radio equipment on the market. Its not the ARRL or hams who have kept silent in these matters that have brought about these changes,  but a handful of dedicated hams who have ranted endlessly about the poor state  of ham equipment design. You and every other ham owes these individuals a lot.

 Its not then surprising that those with a poor technical understanding and who  cant contribute anything to the technical debate nor support  the desire for better equipment who have nothing sensible to say. They like CB'ers  who will buy anything just because its new or has a particular brand name, brain dead consumers. What do you want to be a dummy or technical well informed ham operator? We get  the dummies in here who cant even understand why its wrong using CB amplifiers on the ham bands, and  then we have your types who have no clue why the subject of occupied bandwidth and transmitter IMD is  very important and relevant. Disturbing for a hobby that is supposed to have technically informed participants.



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