Crystals

[george kennie]

I'm sure there will be those who will dispute this, but in my club there
is a very talented electronic guru who is a designer of sophisticated
electronic componentry, which is how he makes his living. One night,
just to satisfy his own curiousity, he took one of his trusty Futaba
PPM  receivers and swapped between channel 11 and channel 59 which was
stuff he was flying at the time, and utilizing a spectrum analyzer was
unable to produce any variation in signal strength across the entire
band. The conclusion he drew was that the manufacturer just mass
produces these receivers en-masse and stuffs them with crystals
according to the system being packaged.These were probably 127- DF units
and relative to the hi-end stuff we fly, there may be a different
approach to our equipment. Tony would probably be able to elaborate
further.This is just info he thought worthy of sharing.
Georgie

Harry Slone wrote:

>  Thanks, all.  This hobby dealer first puts the receiver down on the
> counter....and then says "What crystal do you need?".  I'd better talk
> to him.  Though, I've never had range problems.Harry..
>
>      ----- Original Message -----
>      From: s.vannostrand at kodak.com
>      To: discussion at nsrca.org
>      Sent: Thursday, December 12, 2002 3:13 PM
>      Subject: Re: Crystals
>
>
>
>      No problem.  THe differences are in the receivers, not the
>      crystals.  Just be sure you know if your reeiver is low or
>      high band, then just buy the crystal a channel that the
>      receiver will work with.
>
>      --Lance
>       Forgive my ignorance....  My local hobby store sells
>      receivers, PPM, and separately sells crystals for them.
>      Might be channel 6..or 60.  Could this be a problem?
>
>      Harry..
>
>       ----- Original Message -----
>
>      From:  s.vannostrand at kodak.com
>
>      To:  discussion at nsrca.org
>
>      Sent: Thursday, December 12, 2002 1:59 PM
>
>      Subject: Re: Crystals
>
>
>
>      Tony S can give you the tech detail, but receivers are tuned
>      circuits.  The crystal is key to creating the reference
>      frequency used to filter the signal picked up on the
>      antenna.  The crystal sets up the basic reference frequency
>      and the circuitry around it can only be used for a narrow
>      range, or band, of frequencies.  The futaba receivers come
>      in two types that have components that tune each to a
>      different band.  You can put a low freq crystal in a high
>      band receiver, but you'll have a detuned system, reduced
>      range, and possible signal lock loss.  I wouldn't do it.
>
>      --Lance
>
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