19-07-2017, 07:23 PM
Some months ago shortly after I acquired an SDR dongle ( more here) , I wanted to sweep some VHF, UHF & 1296 MHz filters and was inspired by some articles using noise source generator listings. The author used a device bought on eBay. (Typically a search under "noise source SMA" will reveal some). I don't have a tracking generator so decided to DIY a noise source using a transistor as the noise source plus a couple of MMIC amp stages, power source +12V & broadband noise output level typically around the +5dBm mark on my homebrew power meter.
There are eBay listings at the moment with this type of device at just over $AUD20 including postage and give part of the specs as "Reference ENR: 0.1G/60DB 0.5G/55DB,1G/52DB, 1.5G/48DB 2G/38DB 2.5G/30DB,3G/27DB,3.5G/20DB " but no real explanatory info on "Excess Noise Ratio".
I can only assume +60dB over "standard noise temperature T0 thermal noise" at 100 MHz is a useful value.
The full listing gives...
Features:
Made of high quality material,durable and long use life.
Noise source, generator noise, used tracking generator, jam source
Used special voltage regulator tube, generator white noise and then amplifier. ******** VR tube ???
Directly replace tracking generator.
Excess Noise Ratio noise sources over standard noise temperature T0 thermal noise.
The difference of no input noise source and input noise source signal level.
Specifications:
Material:plastic and metal
Color:green
Product size:80*45*9mm
Package weight:15g
Power: DC12V/0.3A
Output connect:SMA
Reference ENR: 0.1G/60DB 0.5G/55DB,1G/52DB, 1.5G/48DB 2G/38DB 2.5G/30DB,3G/27DB,3.5G/20DB
Package Include:
1 x Noise Source Simple Spectrum External Generator Tracking Source SMA
If these had been available locally (Aus) at the time (rather than just in China), I would probably just have bought one. They are now only a few mouse clicks and 5-7 days away !
The good news is that my high level DIY noise source when used with the SDR did in fact allow me to check the VHF, UHF and 1300 MHz filters out.
Aside from that, I have a number of in-line SMA attenuators that will concatenate to give me >100dB loss at up to 4GHz when I start contemplating measurements on my microwave gear (if ever).
73 Doug VK4ADC
There are eBay listings at the moment with this type of device at just over $AUD20 including postage and give part of the specs as "Reference ENR: 0.1G/60DB 0.5G/55DB,1G/52DB, 1.5G/48DB 2G/38DB 2.5G/30DB,3G/27DB,3.5G/20DB " but no real explanatory info on "Excess Noise Ratio".
I can only assume +60dB over "standard noise temperature T0 thermal noise" at 100 MHz is a useful value.
The full listing gives...
Features:
Made of high quality material,durable and long use life.
Noise source, generator noise, used tracking generator, jam source
Used special voltage regulator tube, generator white noise and then amplifier. ******** VR tube ???
Directly replace tracking generator.
Excess Noise Ratio noise sources over standard noise temperature T0 thermal noise.
The difference of no input noise source and input noise source signal level.
Specifications:
Material:plastic and metal
Color:green
Product size:80*45*9mm
Package weight:15g
Power: DC12V/0.3A
Output connect:SMA
Reference ENR: 0.1G/60DB 0.5G/55DB,1G/52DB, 1.5G/48DB 2G/38DB 2.5G/30DB,3G/27DB,3.5G/20DB
Package Include:
1 x Noise Source Simple Spectrum External Generator Tracking Source SMA
If these had been available locally (Aus) at the time (rather than just in China), I would probably just have bought one. They are now only a few mouse clicks and 5-7 days away !
The good news is that my high level DIY noise source when used with the SDR did in fact allow me to check the VHF, UHF and 1300 MHz filters out.
Aside from that, I have a number of in-line SMA attenuators that will concatenate to give me >100dB loss at up to 4GHz when I start contemplating measurements on my microwave gear (if ever).
73 Doug VK4ADC
Doug VK4ADC @ QG62LG51
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.
http://www.vk4adc.com
This Forum is only going to be as interesting as the posts it contains.
If you have a comment or question, post it as it may trigger or answer the query in someone else's mind.