Thanks for the quick answer. This may be a winter project. PEH's iPad
On Oct 25, 2012, at 10:28 AM, Wayne Burdick <[email protected]> wrote: > A crystal oscillator generally produces something approaching a sinewave, > with varying degrees of harmonic distortion depending on how much output > power the designer was trying to get out of it. > > The XG3's signal is quite stable as it is derived from a crystal oscillator. > But its output will be very close to a square wave, and if the RX/TX stages > that follow don't have a lot of filtering of their own, you'd be better off > filtering the XG3's signal with a simple 5-element low-pass filter. The ARRL > Handbook has examples. > > A crystal oscillator will have one more advantage over an XG3, usually: lower > phase noise. The XG3's phase noise is a relatively constant -105 dBc/Hz at > all offsets, whereas a crystal oscillator might be down to -140 dBc/Hz at 1 > kHz and -150 to -160 at 10 kHz. > > The practical implication of this is that the XG3 should not be used as the > local oscillator for a high-power station (100 W+). That -105 dBc/Hz figure > for phase noise would translate to wideband noise on key-down if you have > hams as neighbors. The phase noise is less of a concern at QRP levels. > > 73, > Wayne > N6KR > > > On Oct 25, 2012, at 10:17 AM, Phil Hystad wrote: > >> Follow on question... >> >> What type of signal (wave?) does a crystal, as used in old rigs like the >> Eico 720, produce? I am thinking that the oscillator of something like in >> the 720, would clean up the output of the XG3 a little bit. I was actually >> thinking of using the XG3 as a crystal replacement type of VFO in my Eico >> 720 but I never even got around to think too much about it (probably because >> I was having too much fun putting together Elecraft kits and operating them). >> >> PEH's iPad >> K7PEH >> >> On Oct 25, 2012, at 10:00 AM, Wayne Burdick <[email protected]> wrote: >> >>> Lee Buller wrote: >>> >>>> Does the XG3 have the stability and output power to be used as a VFO >>>> for older >>>> (1950-60s) CW and Phone rigs like the T-50, DX-40, etc.? >>> >>> Yes, with appropriate level conversion, and possible filtering (the >>> output of the XG3 is closer to a squarewave than a sinewave, so a low- >>> pass filter may be needed). >>> >>> >>>> >>>> Are there software programs that have been written that allows "VFO" >>>> operation? >>> >>> You can use XG3 Utility for this, or write your own app pretty easily. >>> The full command set is documented in the manual. >>> >>> Wayne >>> >>> >>>> >>>> Lee - K0WA >>>> >>>> >>>> >>>> In our day and age it seems that Common Sense is in short supply. >>>> If you don't >>>> have any Common Sense - get some Common Sense and use it. If you >>>> can't find any >>>> Common Sense, ask for help from somebody who has some Common Sense. >>>> Is Common >>>> Sense divine? >>>> >>>> Common Sense is the image of the Creator expressing revealed truth >>>> in my mind. >>>> - John W. (Kansas) >>>> >>>> Never interfere with anything that isn't bothering you. >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[email protected] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>> >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[email protected] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
