Menu

noise source question

Search this Thread

Prev

Previous Post

Next Post

Next

#2

Report Post

Old

May 13th 08, 12:10 AM posted to rec.radio.amateur.homebrew

Doug White Doug White is offline

Doug White is offline

external usenet poster

First recorded activity by RadioBanter: Oct 2007

Posts: 9

Default

noise source question

Keywords:
In article , wrote:
Hello,

I'm willing to make a noise source from an UHF transistor (B-E
junction reverse polarized like a zener) and I was wondering if it's
ok to use the output attenuator as part of the resistor network for
the DC bias of the transistor (or zener). I'd probably look at the
arrl handbook if I had it ;-)

Depending on how you do it, the noise can degrade over time. You are
better off using a diode. My recollection is that a true zener (around
3V) works best. I worked on an HP instrument that was originally
designed with a reverse biased transistor as a noise source. The noise
spectrum degraded over time and caused a lot of warranty returns. I
replaced it with a diode, and all was well. This was 30 years ago, so I
don't remember the details. This was for a low frequency noise source,
and things may behave differently for an RF source.

Doug White

Reply With Quote

Reply With Quote

Thread Tools	Search this Thread
Show Printable Version	Search this Thread: Advanced Search
Display Modes
Switch to Linear Mode Switch to Hybrid Mode Threaded Mode

Posting Rules
Smilies are On [IMG] code is On HTML code is Off Trackbacks are On Pingbacks are On Refbacks are On

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Useful noise source	[email protected]	Shortwave	0	December 12th 07 07:25 PM
Help calibrating a noise source	Gary, WB9JPS	Homebrew	6	October 6th 06 01:19 AM
WTB: HP/Agilent 346A (or B) Noise Source for HP 8970A Noise Figure Meter	Carl R. Stevenson	Homebrew	0	January 21st 04 05:20 AM
SWL/RFI noise source discovery	brass eyelets	Shortwave	3	November 17th 03 04:28 PM
Source of mysterious noise FOUND!	tommyknocker	Shortwave	17	November 15th 03 06:08 AM

All times are GMT +1. The time now is 01:27 PM.

About Us

"It's about Radio"

Contact Us RadioBanter forum home Privacy Statement

Copyright © 2017