IMD is not the only issue, but hey the impact of any amplifier with bad IMD performance affects all ham operators. Do you want the ham bands to sound like the CB band thats full of splatter?
The importance of the IMD issue is also this. There is little point in buying a state of the art transceiver with high performance when a bad IMD amplifier makes performance numbers largely irrelevant. Do hams actually understand this
point or are we just brain dead CB operators who cant understand this simple point.
While I might be ranting and raving continuously on this issue, its a point in radio physics thats important for maintaining the excellent weak signal performance of the ham bands. Look at the ham bands in suburban areas
its almost a waste of time using HF in many suburban locations because of noise pollution. What leg do hams have to stand on when they cant even keep their own act clean? So we going to turn the bands into splattered filled bands full of IMD and splatter from poor amplifiers such as CB amplifiers that cause excessive splatter. We have a duty of care to pass on to the next generation of hams a set of standards that define how we enjoyed the ham bands in the past, operating on bands free of QRM caused from operators and other man made sources..
Anyhow hams who argue against IMD performance I am sorry to say are dummies and simply dont get it.. They rush out bragging about their wonderful transceivers with sky high receiver numbers and cant even understand
that these radios are useless unless transmitters are clean. Its even more importance on the VHF bands. But hey I can understand when people dont have the brains to understand a simple issue like IMD and splatter and carry on like dumb CB'ers with all knobs to the right splattering everyone with bad equipment choices. A not very ham friendly spirit that preserves the excellent resource called the HF bands in a pristine condition free of crud. Hams who cause excessive splatter due to poor operating practices and poor equipment choices are no better than a dumb CB'er who gives no thought to what they are doing nor care too understand the impact of what they doing.
So you can throw all the mud in my direction, I dont mind. At the end of the its only you who looks bad because you so ignorantly dont fully understand the importance of the issue. There are a great number of hams who have technical expertise who understand this issue and say nothing. Its only the loud mouth know nothings who make the same old lame attacks about no callsign or other trivial rubbish. Why dont you address the issue of IMD and show us your genius and explain why amplifiers with poor IMD has no impact on hams and the ham bands. I would be interested in your arguments. I am sure so would many hams would also be interested in another view rather prattling on about nothing. Nobody else can produce a counter argument as to why a crap IMD CB amplifier or any crap amplifier for that matter is good for the ham bands. The floor is yours SIR!
When the ITU considers these standards necessary for professional HF users, I cant take comfort that I am on the right side of the argument. How confident are you in your argument against the best possible IMD standards?
Nobody mentions how important the issue of spectral cleanliness of amplifiers. Tubes and solid state amplifiers with poor IMD performance should really be placed at the bottom of your list.
You cant rely on the ARRL reviews to tell you how clean the amp is. The ARRL simply ignores the issues and does not care if the AMP Is dirty. Every piece of crap spewing out IMD garbage is OK by them if they review it.
An example is the review of the Acom 1500 amp in this months QST. -27db 3rd order and -49db 9th order. Rather unspectacular figures yet they say nothing about such amplifiers. A 8877 as comparison has superior IMD performance. The current batch of solid state amplifiers are also rather poor performers but the ARRL just keeps on reviewing like everything is well. Hear no evil see no Evil!
If I was shopping for a decent tube or solid state amp I would by the model that produces the cleanest signal. Clean means no tetrode amplifiers, poorly designed solid state and CB amplifiers. Manufacturers like Tokyo High Power and other are stuffing industrial RF fets into their amplifier designs. These FETS are not linear RF devices meant for linear SSB service. The outcome is a dirty amplifier designs that have poor IMD performance that is no better than a crap CB amplifier.
My god this is the same topic you have posted in at least two different threads this morning. Why not try writing a letter to your senator. The amps discussed meet or exceed FCC requirements. If you want companies to do better, petition the FCC to change their standards.
AD9DX,
Thank you , thank you, I also have become very tired of Mr. (I have no callsign), (one tune) Zenki. To him IMD is the
ONLY thing that matters, and his one man campaign of criticizing almost every amplifier made today for IMD is getting real old. Zenki, you have made your point
HUNDREDS of times, give it a rest.
John W5JON - V47JA
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