tag:blogger.com,1999:blog-8085571700321121668.post7724676771184776941..comments2024-03-08T17:30:40.138+01:00Comments on EA4EOZ, an amateur radio electronic enthusiast: Modifying BG7TBL noise sourceMiguel A. Vallejo, EA4EOZhttp://www.blogger.com/profile/04739647349389027008noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-8085571700321121668.post-18884763378466981752022-07-21T23:56:34.086+02:002022-07-21T23:56:34.086+02:00I have successfully used anti static foam to suppr...I have successfully used anti static foam to suppress oscillations. It is conductive so glue it on the lid and make sure you have a barrier to your circuit.Johnhttps://www.blogger.com/profile/09015952853472451335noreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-64589754909252144622016-05-28T09:02:44.032+02:002016-05-28T09:02:44.032+02:00Another thought for oscillation suppression. Mari...Another thought for oscillation suppression. Marie Callender Chicken Pot Pies have a sheet of microwave absorber in the box in order to heat up and brown the pie in the microwave. It's a thin metallized sheet of plastic and I think it would also do a good job of being a lossy item in the cavity.<br />Regards,<br />Charles R. PattonAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-34765424080336993582016-01-08T17:08:51.556+01:002016-01-08T17:08:51.556+01:00Since this is probably the most visited page about...Since this is probably the most visited page about this noise source, I'll just leave a note here.<br />For those exceptionally lazy persons like me, you can just replace the zener diode with 12V one. Cut its pins as short as possible and solder it.<br />Power the device with your usual 12V wall-wart (mine gives 12.3V actually) and voila, no more that "hot PCB smell".<br />Sure, MMICs will run underbiased thus less gain, but RFExplorer still shows approx. -50db at 1GHz. Maybe smaller diode with less capacitance would help (the one I used is larger than original).<br />But as a quick fix for those without 1W SMD resistors at hand I think it's OK.<br />/ de RA9OEKAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-35473158445605885572015-03-19T14:06:30.973+01:002015-03-19T14:06:30.973+01:00Hi Eduardo,
Please, send the plot to me. I consid...Hi Eduardo,<br /><br />Please, send the plot to me. I consider buying one of those. How does it look in the range 2GHz to 4.4GHz?<br /><br />Thank you!<br /><br />Kind Regards,<br />VelkovTsvetelin Velkov LZ1TVVhttps://www.blogger.com/profile/01794555870041060254noreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-57124041230797727182014-12-22T15:31:14.707+01:002014-12-22T15:31:14.707+01:00Hi Miguel.
Great post. Thanks.
I just measured a 2...Hi Miguel.<br />Great post. Thanks.<br />I just measured a 2014 12Volt version of the BG7TBL. See Aliexpress. Check for 2014... on the photograph. Price is 2..3 € higher.<br />It has a step-up converter to generate 39 Volts on the zener diode.<br />Flatness is quite good. I can send it to you if you whish.<br />Un saludo.<br />EduardoAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-107637245729019132014-08-18T19:31:43.035+02:002014-08-18T19:31:43.035+02:00Probably it has too much gain. If you really need ...Probably it has too much gain. If you really need a gaussian noise source try to remove one of the MMIC amplifiers, the one close to the output. It should work.Miguel A. Vallejo, EA4EOZhttps://www.blogger.com/profile/04739647349389027008noreply@blogger.comtag:blogger.com,1999:blog-8085571700321121668.post-65925280780722792162014-08-18T15:29:22.617+02:002014-08-18T15:29:22.617+02:00The original untouched board has another con, whic...The original untouched board has another con, which is the noise is not fully gaussian. while this not may be a problem for a poor-man's tracking source, it is a problem if you require the gaussian distribution. Observing the noise with a high speed scope I saw that the noise is saturated at one end (and consequently there is some dc level at the output). I guess this over gain related issue can be tackled by your solution - I admit I didn't yet tested your changes.Anonymousnoreply@blogger.com