8014	2013-01-02 06:24:35	Nick F	Phase Noise measurements on BITX VFO and other oscillators
Message	Date	From	Subject
Hi All, Today I've done some phase noise measurements and I created a web page with details of how it all went. You can see in there if Farhan's BITX oscillator (http://www.phonestack.com/farhan/bitx.html) is any good and how many other oscillators I built outperformed this simple design. http://users.tpg.com.au/nfieraru/Electronics/RF_Oscillators/Phase%20Noise%20in%20RF%20Oscillators.htm Once I have better results of any sort or new information, I will update the document. I will also add some photos of the home-made oscillators I tested. Regards, Nicolae
8015	2013-01-02 06:31:08	Weddig, Henning-C...	Re: Phase Noise measurements on BITX VFO and other oscillators
NEVER ever use zener diodes to stabilize the VFO, these diodes have a too high amplitude noise which converts into pohase noise (floor) of the VFO! Henning DK5LV Am 02.01.2013 11:32, schrieb Nick F: > Hi All, > > Today I've done some phase noise measurements and I created a web page > with details of how it all went. You can see in there if Farhan's BITX > oscillator (http://www.phonestack.com/farhan/bitx.html) is any good and > how many other oscillators I built outperformed this simple design. > > http://users.tpg.com.au/nfieraru/Electronics/RF_Oscillators/Phase%20Noise%20in%20RF%20Oscillators.htm > > Once I have better results of any sort or new information, I will update > the document. I will also add some photos of the home-made oscillators I > tested. > > Regards, > Nicolae > >
8016	2013-01-02 07:25:44	PY8ELO - Silva	Re: Phase Noise measurements on BITX VFO and other oscillators
Hi Nick, I wish You a HNY 2013 to You and yours!!! I cant open the links. Are there something wrong? On 02-01-2013 07:32, Nick F wrote: > > Hi All, > > Today I've done some phase noise measurements and I created a web page > with details of how it all went. You can see in there if Farhan's BITX > oscillator (http://www.phonestack.com/farhan/bitx.html) is any good > and how many other oscillators I built outperformed this simple design. > > http://users.tpg.com.au/nfieraru/Electronics/RF_Oscillators/Phase%20Noise%20in%20RF%20Oscillators.htm > > Once I have better results of any sort or new information, I will > update the document. I will also add some photos of the home-made > oscillators I tested. > > Regards, > Nicolae > > -- ************************************** Brazilian Ham Radio - ARRL Member Callsign: PY8ELO Name: Silva Grid Locator: GI25ar Address: POBOX 151 CEP 68180030 ITAITUBA - PA - BRAZIL ************************************** "The quieter You become the more You are able to hear" [Non-text portions of this message have been removed]
8017	2013-01-02 18:24:31	Jim	Re: Phase Noise measurements on BITX VFO and other oscillators
Just wondering ... what provides the voltage reference in a fixed-voltage regulator? The commonly applied "fix" for the BITX20 8V zener is an LM7808 or functional analogue. 73 Jim N6OTQ >________________________________ >
8018	2013-01-02 18:45:42	Niels Moseley	Re: Phase Noise measurements on BITX VFO and other oscillators
Hi Jim, Usually some type of bandgap reference: http://en.wikipedia.org/wiki/Bandgap_voltage_reference 73, Niels PA1DSP. On 2 jan. 2013, at 21:16, Jim <n6otq@yahoo.com> wrote: > Just wondering ... what provides the voltage reference in a fixed-voltage regulator? The commonly applied "fix" for the BITX20 8V zener is an LM7808 or functional analogue. > > 73 > Jim N6OTQ > > >________________________________ > >
8019	2013-01-03 07:08:59	drmail377	Re: Phase Noise measurements on BITX VFO and other oscillators
Yes, perhaps use a battery with low ESR to power your oscillators when doing comparative phase noise measurements. Bypass and shield, avoid ceramic capacitors (which can cause microphonics especially close-in). FWIW - 73's
8026	2013-01-03 23:01:49	Jim	Re: Phase Noise measurements on BITX VFO and other oscillators
Hi Niels I believe that this is correct for the variable-voltage regulators, and I do know that you can add voltage (or current?) dividing resistors
8027	2013-01-03 23:01:49	Nick F	Re: Phase Noise measurements on BITX VFO and other oscillators
Hi Drmail377, Your suggestion of using a battery for testing is very good, also I am aware about shielding and bypassing, I'll have to get a metal enclosure when testing oscillators. My intention for the future is to build a very low phase noise VFO and then to tackle one problem at a time and perhaps, compare individual components, such as effects
8028	2013-01-03 23:01:49	Nick F	Re: Phase Noise measurements on BITX VFO and other oscillators
Hi PY8ELO, HNY to you too! You can't access the link maybe because I left some spaces in the file name and some browsers don't know how to treat them. I decided to create a main entry page, where there are links to all documents I created so far. So in the future, it will be better to use this link http://users.tpg.com.au/nfieraru/ If you still have problems, please let me know. Regards, Nicolae