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Dave Heil wrote in message ...
Len Over 21 wrote: In article , (Brian Kelly) writes: (Len Over 21) wrote in message ... In article , PAMNO (N2EY) writes: In article , (Brian Kelly) writes: Whatever you say. You can imagine getting within 10 Hz of the correct frequency with the '50s designs all you want...but that won't make it happen. What?? Where, exactly, has anybody claimed 10Hz frequency resolution with '50s analog radios? As you will say later, those "analog" radios have INFINITE resolution. :-) Note the avoidance of answering the question ;-) Creative PLL and DDS subsystems of today, designed by others, make it possible for anyone to select 10 Hz increments on any HF band (30,000 frequencies within 300 KHz) with crystal- controlled accuracy. Analog VFOs are continuously variable. Making it possible for anyone to select an *infinite* number of "increments" within a 300Hz bandwidth much less your coarse 300 Khz wide example. Heh heh heh...your bafflegab won't win blind man's bluff, Kellie, deal yourself a better hand... :-) Note the avoidance of the facts. ;-) Feel free to try to state you can return to that "infinite possible" setting within a few PPM...all without any old crystal calibrator and dependent on that "coarse" analog dial. :-) Note that the importance of this feature is not explained ;-) And they do it without generating any phase noise or other forms of crud synthesizers toss out. Kellie, define "phase noise" insofar as amateur radio operation is concerned. You, for the limits of your technical knowledge, should call that "incidental FM" which is what the industry term "phase noise" refers. :-) Then you should examine exactly how low that terrible phase noise is. You can use the term "dbc" referring to the number of decibels below the "carrier" (center frequency reference, not a modulated carrier per se). The "crud" (as you term it) is quite far down in relative power and certainly won't affect morse code reception of an on-off keyed station's carrier. "Phase noise" is a somewhat new buzzword in industry due to the importance of keeping it low for QAM signals (Quadrature [phase] Amplitude Modulation, a combination of PM and AM). The cell phone engineers will know of that importance on keeping the BER (Bit Error Rate) as low as possible. The amount of work in the last decade on cellular telephony techniques has been enormous worldwide. It's only natural that industry advertisements, from sub- system components to full systems, emphasize a low "phase noise." As far as on-off keyed radiotelegraphy, your mention of "phase noise" as being "crud" in synthesizer frequency control is akin to making a big case for gold-plated music system speaker wires. :-) Once again, you've demonstrated that you know very little about problems with much of the amateur radio equipment produced within the past couple of decades. Noticeable phase noise appears not only in the receiver output section of many transceivers but in the transmitted signals as well. 1980's top of the line Kenwood TS-930's were rife with the phase noise products and synthesizer spurs. A quick spin of the main tuning dial with no antenna connected would result in a rapid p-t-t-t-t-t-t-t-t sound from such spurs. R.L. Drake's TR-7 had much less phase noise. Rigs such as Ten-Tec's Omni VI series, using a crystal mixed front end had almost no measureable phase noise. The main importance of phase noise in amateur HF reception is that it causes the apparent noise floor to rise when a strong signal or signals is close to the desired signal frequency. If you are trying to receive a -130 dBm signal and a strong signal a few kHz away mixing with a noisy synthesized LO causes your receiver's noise floor to rise to -120 dbm, you're out of luck. And the amateur HF bands are often full of strong local signals adjacent to the weak ones we want to work. The folks in Newington whom you frequently enjoy insulting might put you on the road to being informed: http://www.arrl.org/files/infoserv/tech/bestrig.txt under "Q. What do you mean by receiver 'cleanliness'"? You may continue your education by looking at the following pdf file under section 1.2.2: http://www.qth.com/inrad/managing-interference-ch1.pdf One of the Polish fellows has published some excellent information. The phase noise issue is touched upon in the last few paragraphs: http://www.gmdx.org.uk/dxtest/qx9racze.pdf All good stuff. Note how well a certain kit transceiver performs... I rather prefer what I've been exposed to since 1963 on frequency control methods... Stuck in the past. ;-) beginning with those "cruddy" synthesizers (without "real" frequencies, only the "synthetic" variety)...and quartz crystal oscillator accuracy and stability to the 10 PPB region. Perhaps it is time to update your database, Leonard. To at least 1980s levels ;-) USING modern equipment is NOT involving development or anything else. This gives us cause to wonder..... What amateur radio equipment has Len developed? What amateur radio equipment has Len actually used, and in what environments? (The contest environment is quite different from the "quiet band" environment) How many contest points/countries/states/contacts has Len made with amateur radio equipment he developed/designed/built/paid for himself? What articles on amateur radio receiver performance issues such as dynamic range (third order IMD, BDR, etc.), phase noise, etc., has he authored? Or even actually read and understood? The world wonders....;-) Try not to run off at the mouth/keyboard so hastily. Try taking your own advice ;-) Try not to nit-pick like nits over minor phrases in postings so that you have an "excuse" to cuss and snarl at NCTAs. What minor phrases? Len claimed that frequency synthesizer rigs were necessary for the "subdivisions" of 1968. Numerous positngs by different authors, all of whom actually had to deal with those "subdivisions" have proved that to be utterly false and without basis. Len, of course, never had to deal with them at all because he's never been a radio amateur and never operated an amateur radio station. (By FCC definition, operating requires a license). It makes you look like nursie's cousin. :-) NOT USING modern equipment but attempting to spout off like you have some knowledge of what is being discussed is making you look like N0IMD's antenna advisor. Not using, not owning, not building, not developing...... Of course, to the knowledgeable reader, Len's postings simply reveal how truly ignorant he is of amateur radio in many ways. That's not a crime, of course, but it does get boring. His posts also reveal how resistant is he is to new ideas and information, when presented to him from certain sources he deems inferior. 73 de Jim, N2EY |
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