Ken - Who said vacuum tubes were outmoded? Any more good reports like that one, and Drake might decide to start manufacturing the 4-line again! Can you imagine a T9/R9 combo?
Terry K7WLD -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ken Bessler Sent: Friday, September 28, 2007 4:49 AM To: [EMAIL PROTECTED] Subject: [drakelist] Noise floor measument on a TR4 I just built an Elecraft XG-2 test generator. For those who don't know the model, it's a high accuracy (output level -107dbm +/-1db) 80/40/20 meter RF generator. I've used it in the past to determine the Minimum Discernable Signal or noise floor of a reciever. Here are some of the past results I've gotten: Elecraft K2 #4913 -143dbm Kenwood TS-850SAT -136dbm Yaesu FT-920 -137dbm Now to the good stuff - my recently aquired TR4: 20m: -147dbm 40m: -152dbm 80m: -151dbm To measure this I injected the generator's -107dbm (1 microvolt) signal and measured it's peak then measured the noise next to the carrier and did a little math. I also measured the same spot with the generator on and off. My numbers might be off because I could not turn off my AGC but to correct for this I made measurements at many differant "RCVR GAIN" settings on the TR-4 and averaged them out. I found that with the gain set to anything less than 11 o'clock, there was no AGC action. I used "Rocky", a SDR program that shows the spectrum around a signal like a pan adapter. I also ran the tests witn "Spectrogram", a spectrum analyzer and got very close to the same numbers. Another impression is by my ears - the -107dbm signal seemed to be easiest to pick out of the noise on the TR4 than the other rigs. BTW the 50 microvolt setting produced a S9 signal on all three bands. The main reason I wanted to test the MDS of my TR4 is the fact that the reciever is sooooo quiet that I got the impression that it was deaf or broken..... Deaf? NOT! I've only been a Drake owner for 5 days but I'm quickly becoming a fan! 73's de Ken KG0WX - Kadiddlehopper #11808, Flying Pigs #-1055, Grid EM17io _____ Get news, entertainment and everything you care about at Live.com. Check it out! <http://www.live.com/getstarted.aspx%20>
