d3eb9211   
   XPost: rec.radio.shortwave   
   From: et472@ncf.ca   
      
   On Sun, 27 Nov 2011, NT wrote:   
      
      
   > If I were designing such a product, I'd do everything in my power to   
   > avoid end user alignment with testgear, for one very simple reason: it   
   > wipes out 99.9% of your potential customers, its business suicide.   
   >   
   > Perhaps one could use resonators instead of LCs, if you dont like the   
   > interstation garbage of agced reaction.   
   >   
   >   
   And Heathkit is the model for that.  They'd prealign tuned circuits,   
   they'd have certain stages as preassembled modules, they'd build some   
   relevant test equipment into the equipment (like those tv sets with some   
   sort of metering in the back). One I always liked was a scanner, they   
   included some parts to make up a 10.7MHz oscillator and mixer.  The   
   oscillator would provide the signal to align the IF strip, and then you'd   
   mix the local oscillator with this outboard oscillator/mixer to get a   
   signal on the signal frequency, to align the front end.   
      
   Heathkit of course did design for the beginner, I gather once they had the   
   instructions together they found people who had never put a kit together   
   to follow the instructions so they could make sure they made sense (and if   
   followed properly, would result in a working piece of equipment).   
   Despite the fuss about Heathkit being for the hobbyist, they always had   
   taht color tv set, that musical organ, that boonie bike, that were   
   aimed at people who just wanted something cheaper, and were willing to   
   put some time into it.  But that's why Heathkit shut down the kits, with   
   time the sorts of things their was interest in got so complicated (and   
   parts so small) that it was no longer cheap to come up with the   
   instructions, pack the kit compared to just building it at the factory.   
      
   As for ceramic resonators, I think that is a key point.  Design is the   
   overall results.  When companies put in ceramic resonators in everyday   
   radios, they did away with a large part of the alignment, so even if the   
   resonators were more expensive than IF transformers (I don't know) the   
   reduction in alignment time was still significant.   
      
   As I pointed out, move to a higher IF, you may pay more for an IF filter,   
   but you can do away with the need to gang the front end tuning with the   
   local oscillator, which simplifies things mechanically but also gets rid   
   fo a lot of troublesome alignment.  It's relatively easy to get two stages   
   of front end tuning to align together, just go for a peak, but ganging it   
   with a local oscillator is more complicated.   
      
   The superhet alone is a concept that complicates something to make other   
   things easier.  Make things more complicated, the mixer and oscillator,   
   and you dont' have to fuss with multiple stages on the RF frequency.   
      
   Sometimes the "simplest" solution ends up with more work than the more   
   complicated one.   
      
      Michael   
      
   --- SoupGate-Win32 v1.05   
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