>It all depends on how accurate you want your frequency to be.  I >doubt a n   
   analog scope will get to with in a few cycles at 150 >MHz.      
      
   It won't, but you don't always need that much accuracy. I know ways around all   
   kinds of things. Want to adjust the free run of the 38KHz oscillator in an FM   
   tuner ? Who needs that accuracy ? Radio stations. So you just put your scope   
   in free ruin and    
   rock it in to the frequency when it is locked to a station. Then you off tune   
   it and use the frequency control on the FM tuner to make it stationary. Now   
   you can get to fractions of a Hertz. Same thing with the old 3.579545 MHz   
   oscillators in color TVs.    
   Before SAW filters, the IF frequency in a TV was not critical at all, you   
   could align those coils to quite a range and have it come out right. Before   
   the ceramic filters in FM IF strips, which are almost the same as a SAW   
   filter, that 10.7MHz was not    
   critical either. In an AM tuner, the IF can be anywhere from like 420KHz to   
   490KHz and it'll work just fine.    
      
   I lived for decades without a frequency counter. And it would not have come in   
   handy with some of the frigged up things I have had to do.    
      
   Here's an example. Remember how VCRs work ? Video carrier is FM at 4.2MHz,   
   color under is hetrodyned down to 629KHz. in the more extended play time   
   speeds there is no guard band between the slashes on the helical scan tape and   
   the chrome bleeds from    
   track to track so they rotate the absolute phase (which includes the burst)   
   90º which makes the crosstalk cancel out by use of a COMB filter.    
      
   So I was working in Willowick, Ohio which is a bit of an unusual demographic.   
   People there don't really have alot of money, but all those $150,000 houses   
   out there they bought for $35,000 many years ago. There were incompetents out   
   there and one of them    
   was actually named Jeff, which was almost a concern for me... Had one old   
   Italian guy whose bigscreen he screwed up. he says "Some years ago that guy   
   would not have walked out of here". Nice to make your acquaintance, and I   
   actually mean that. If you had    
   a convergence problem this guy's solution was to defocus the affected tube.   
   Now if that isn't bad enough we were getting in a bunch of Funai built VCRs   
   that would not record.    
      
   Someone had screwed with some controls, carrier frequency, deviation, white   
   clip, all that in the FM modulator for the recorder. That requires thousands   
   of dollars in equipment to align properly.    
      
   Well it did.    
      
   I stuck a dummy tape in a VCR and hit play. I loosely coupled the signal going   
   to the record heads on the defective VCR to the one in play with the dummy and   
   it picked up the signal just like it would if it were playing a tape. Easy.    
      
   That is how to get shit done and why I got how I got so how I got. Other shops   
   would just condemn them but we stacked them up, seventy bucks, seventy bucks,   
   seventy bucks. I could do about ten of them in a day. Probably more.    
      
   And FM alignment, I can do it just fine with an air signal. The only thing I   
   can't do is the stereo separation but I got that solved now. Those little FM   
   transmitter for send like your CD or MP3 player to your car radio ? Those   
   things are all digital,    
   the separation out of them is perfect. There is really not much to adjust on a   
   digital stereoplexer. Frequency ?    
      
   All a digital stereoplexer does is switch between the two channels at 38KHZ   
   generating a DSB suppressed carrier signal, then puts that to a flip flop to   
   make the pilot frequency and filters it to a sine wave. Oh, and I suppose that   
   must be adjusted for    
   phase... big deal. I can figure that out with any FM stereo tuner which   
   doesn't even have to be aligned for separation, just adjust the phase for   
   maximum L-R, separation that is.    
      
   That is how it is done. Up until a couple years ago I never owned a frequency   
   counter. In fact now in the last couple of years I think I have used it about   
   five times, and two of them were just playing around with it.    
      
   So I got me a nifty HP 5314A. I am thinking of taking it off the bench on onto   
   the shelf. I am not in a hurry though, I have nothing to put there right now.    
      
   One thing irks me about this HP, I don't know if the input level controls go   
   up or down when clockwise. (or whichever) It is not in the manual, I started   
   looking for it on the print but it does not specify.    
      
   Well it's HP so what did I expect ? I will not buy their computers. I think I   
   got my last HP printer. It is a great printer but it costs $300 to fill it.    
      
   You can throw a frequency counter together fairly easily. All you need is a   
   digital (as in base ten) counter, and oscillator and something to gate it   
   accurately. You know the operation of a DVM is not all that different. It has   
   a calibrated gate but the    
   signal is current controlled by the input ramping up a calibrated cap. There   
   are also cap checkers that work in a similar fashion.    
      
   When I first started, and that involved fixing things under the bench...all I   
   had was a VTVM. I remember my first dog. Color killer control works but no   
   color lock, barber pole effect. I have no idea how many people tried to fix it   
   but I am the one who    
   did. The color killer control, like a 1.5 meg or whatever feeds the burst gate   
   tube with the proper pulse to only allow the burst through which then locks   
   the local oscillator. the wiper varies a pulse to the color killer circuit,   
   which was only there to    
   reduce noise on black and white shows, but in this case the pot was open. It   
   had a bad spot. You rotate the control and the color would come in and go out   
   as expected but no sync. The pulse was there at one side but not at the other.   
   The point though is    
   that the pulse off the flyback which is what runs all this was not getting to   
   the burst gate where it was specifically needed.    
      
   I also invented the dim bulb tester. Sure other people also did, but I did. I   
   ran down a short in a clothes dryer. We lived in a rental and the place had a   
   fuse box. some things re out upstairs and this one fuse keeps blowing.    
      
   We tried yanking stuff, unplugging and changing the fuse but they kept on   
   blowing. Finally I said "Gimme a light bulb". It was the same socket back   
   them, and the bulb lit. I unplugged the dryer and it went out. Problem solved.   
   I also figured out how to    
   do it with cars.    
      
   Frequency counter ? Just put the probe in my mouth and wait for a number. Then   
   to determine if it is GHz or MHz note if my testicles are in my neck. Why   
   spend all that money ?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)