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*Subject*: [amsat-bb] Re: New Preamp*From*: Edward Cole <kl7uw@xxxxxxxxxxxxx>*Date*: Wed, 19 Sep 2007 22:14:49 -0800

I'll need to revisit these as it has been awhile since I looked in my Microwave Exp. Handbook. I will make one comment on the noise temperature formula that Bob Atkins shows in his article. There several terms left out making the formula under-estimate noise temp. for cascaded stages of receiver. I puzzled over this long and hard back in late 1990's and finally modified the formula to include the missing terms. You can see the corrected formula by downloading the spreadsheet: http://www.kl7uw.com/emelink.xls This spreadsheet will calculate effective receiver noise temp for a cascade of three receiver stages, then estimate the total system noise temp. With that one can enter antenna, transmitter, and feedline losses to arrive at eme link performance. Note this program is limited accuracy to under 500-MHz. For an expanded formula appropriate for mw frequencies see: http://www.kl7uw.com/mwemelink.htm http://www.kl7uw.com/emeOVROcalc.htm shows the derivation of the mw version 73 Ed - KL7UW At 02:21 PM 9/19/2007, i8cvs wrote: >----- Original Message ----- >From: <k0vty@juno.com> >To: <kl7uw@acsalaska.net>; <domenico.i8cvs@tin.it>; <amsat-bb@amsat.org> >Sent: Wednesday, September 19, 2007 6:53 PM >Subject: Re: [amsat-bb] Re: New Preamp > > > Thanks to Dom and Ed. > > > > From you two gentlemen, a few words please on field proofing antenna > > systems using sun noise and a EME signal should add nicely to this > > discussion. > > > > Joe K0VTY > > Amsat #860 > >Hi Joe, K0VTY > >About this matter the best I can suggest is to read the following >articles: > >"Noise Temperature,Antenna Temperature and Sun Noise " >by Bob Atkins, KA1GT > >"Microwave Systems Calibration Using the Sun and Moon" >by David B. Shaffer, W8MIF > >Both articles are published in the ARRL UHF/Microwave >Experimenter's Manual ARRL Order No. 3126 > >73" de > >i8CVS Domenico 73, Ed - KL7UW ====================================== BP40IQ 50-MHz - 10-GHz www.kl7uw.com 144-EME: FT-847, mgf-1801, 4x-xpol-20, 185w DUBUS Magazine USA Rep dubususa@hotmail.com ====================================== _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

**References**:**Re: New Preamp***From:*k0vty

**Re: New Preamp***From:*i8cvs

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