Log in
Register
Menu
Log in
Register
Home
What's new
Latest activity
Authors
Forums
New posts
Search forums
What's new
New posts
Latest activity
Members
Current visitors
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Satellite TV receivers & systems support forums
Fringe Reception General
0.01dB lnb?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="ouagadougou" data-source="post: 191065" data-attributes="member: 187470"><p>Y Factor Measurements are the standard way to measure the Noise Temperature of a complete receiving system. You compare the noise output difference between a hot temperature like the ground and a cold part of the sky by moving your dish from one to the other and measuring the noise output change from your receiving system, there are a number of noise sources you can point your dish at to do these measurements. The bigger the difference in dB in this case the lower the noise temperature of your LNA/LNB. Because you know what the ground temp is and you know the difference in dB after this measurement you can then convert back and calculate your actual system noise temperature. When you have your system working well and with a big enough dish its quite easy to measure the noise output from the moon.</p><p></p><p>If you want to measure an amplifier on its own then a calibrated Noise Figure Meter is the easiest way to do this but you can build your own equipment that will do the same job for a lot less money. On my 2m dish I can quite easily see the movement on a normal analogue sat meter when I put my hand over the feedhorn this way my hand is hot and the sky temp is cold.</p><p></p><p>Maser amplifier noise temperatures depend on the type of cooling and the refridgerator temperature used but noise tmeperatures down to 3 or 4 kelvin are possible this equates to a noise figure of 0.04dB. The cooling systems are very complex and difficult for us to use at home.</p></blockquote><p></p>
[QUOTE="ouagadougou, post: 191065, member: 187470"] Y Factor Measurements are the standard way to measure the Noise Temperature of a complete receiving system. You compare the noise output difference between a hot temperature like the ground and a cold part of the sky by moving your dish from one to the other and measuring the noise output change from your receiving system, there are a number of noise sources you can point your dish at to do these measurements. The bigger the difference in dB in this case the lower the noise temperature of your LNA/LNB. Because you know what the ground temp is and you know the difference in dB after this measurement you can then convert back and calculate your actual system noise temperature. When you have your system working well and with a big enough dish its quite easy to measure the noise output from the moon. If you want to measure an amplifier on its own then a calibrated Noise Figure Meter is the easiest way to do this but you can build your own equipment that will do the same job for a lot less money. On my 2m dish I can quite easily see the movement on a normal analogue sat meter when I put my hand over the feedhorn this way my hand is hot and the sky temp is cold. Maser amplifier noise temperatures depend on the type of cooling and the refridgerator temperature used but noise tmeperatures down to 3 or 4 kelvin are possible this equates to a noise figure of 0.04dB. The cooling systems are very complex and difficult for us to use at home. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Satellite TV receivers & systems support forums
Fringe Reception General
0.01dB lnb?
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
Accept
Learn more…
Top