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Texas star dx667v turbo mod
- Thread starter radioman24
- Start date
I already agree with you that it's common practice to overdrive amplifiers on 11 meters. Just because everyone is doing it and they don't blow up and do get good reports sure is a long way from saying the amp is running clean. Clean is a relative term that means nothing unless you're looking at the spectrum analyzer when you claim it.
How you can defend the practice of driving a transistor with more then 10 times it's rating and suggest it's still running clean is ridiculous. That's probably why you went from 45 watts PEP down to as little as 15 watts PEP on normal voice peaks. Because it's impossible to make a 2SC2290 stage run clean with 45 watts PEP applied. Read up on things like intermodulation distortion, transistor saturation, and collector dissipation.
Well, how can you defend the practice of saying "clean" isn't "clean."
The typical CB radio ratchetjawer goes by what he hears. Not by what he sees on any poo tube. If it sounds clean then it is clean. And that's good enough. So what if an amp is being over-driven by a few watts? It's inconsequential. It's not hurting anything. It's like talking with a 1.3 SWR. It doesn't matter.
Attention CBer's. Now hear this. You will participate in the following poll. Raise your hands if you have a 1) Oscilloscope 2) Spectrum Analyzer and 3) Communications Service Monitor and use these instruments continuously, particularly while mobile, to determine that your signal, and the signal of the CabOver Pete that the good buddy you are talking to is driving, is specturally pure and be as white as the driven snow...and all.
I concede you the technical points Mister Shockwave.....but methinks you protesteth too much and are otherwise befogged by overmuch thinking. We're just a bunch of poor 'ol dumb country cber's and we're mostly only worried about where our next Budweiser is coming from; and we could care less if our sphincter lines are off a few db's on some $5,000 techno box that none of us have anyway.
If it sounds good, hear it!
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Wire weasel, I understand that most don't have access to this type of test equipment however, you don't need it to see the effects of an overdriven amplifier on 11 meters. Just listen to channel 5 or 7 the next time skip opens up on the bowl. All that flat topping and RF cutoff sure creates a lot of adjacent channel interference. My only point here is backing the drive down to a sensible level will not cause any reduction in true modulated power output on an amplifier but it will make the claim of running clean accurate and improve fidelity.
specially matched components than no one else can purchase because he has a contract with the device manufacturer.
that funny you remember that... its funny i still do
Yeah I hear ya. But I don't scare that easily and I hope most others don't either. Citing the worse offenders from channel 6 is hardly a commonplace example.
CB remains the wild wild west. Few operators conduct their stations with their neighbor's ears in mind. Folks just wanna talk and have a little fun with radios.
Hams are only a little better by degree. I'm a General and there is just as much spectral impurity and rule breaking on the ham bands as there is on CB.
Life's too short to sweat the small stuff.
Go forth and fun with radios
I've been an advanced class for 15 years and while rule breaking has increased since the no code, I can't for the life of me remember the last time I heard someone take something like a 5 "pill" on the 80 meter band and drive it with 45 watts PEP. Once you remove the 10 KHz channel spacing you find on 11 meters and start squeezing a QSO in every 3 KHz, spectral purity becomes less of an option and more of a requirement.
While the educational value in some of these posts may be lacking, the entertainment level is higher.
You're not paying attention to everything said swanny. Medium power radios DO provide the proper maximum drive into low drive transistor amps as with normal ordinary talking, they put out 15-20 watts...which is just right.
Good luck!
Swanny, for a junior member your operating practices seem to be beyond a few of the "more experienced". Once you realize you truly have to double your output power to notice the slightest half an S unit (3 db) increase, it doesn't make any sense to overdrive your amp. Once the amp flat tops, more drive just fakes the watt meter into showing a little bit more power because of the DC component the flat topping represents to the meter.
The wise person would disregard anyone that tells you a medium drive radio is appropriate for a low drive amp. The names alone indicate a direct contradiction in that advice. By the way, 15 to 20 watts maximum is indeed a low drive radio like the 148GTL Swanny suggested. The standard 4 watt carrier is 16 watts PEP when 100% modulated. Plenty of drive for the DX667V.
The wise person would disregard anyone that tells you a medium drive radio is appropriate for a low drive amp. The names alone indicate a direct contradiction in that advice. By the way, 15 to 20 watts maximum is indeed a low drive radio like the 148GTL Swanny suggested. The standard 4 watt carrier is 16 watts PEP when 100% modulated. Plenty of drive for the DX667V.