Roy I did have a HP 8566A before replacing it with the 70000 series. Same size and weight. Bert Kehren In a message dated 9/26/2011 6:27:59 A.M. Eastern Daylight Time, phill...@btinternet.com writes:
Bert What's your opinion of the "old" HP8568B with its max. frequency range of 1.3 Ghz and its weight of around 100 lbs. - are the more recent instruments that much better ? Roy -------------------------------------------------- From: <ewkeh...@aol.com> Sent: Sunday, September 25, 2011 10:47 AM To: <time-nuts@febo.com> Subject: Re: [time-nuts] Any thoughts on best rubidium? > If you want low noise in a spectrum analyzer it all comes down to the > signal quality into the first mixer. Every thing else with today's > technology > is down hill. > Bert Kehren > > > In a message dated 9/25/2011 5:32:31 A.M. Eastern Daylight Time, > rob...@delien.nl writes: > >> One other thing is that some spectrum analyzers aren't really designed >> for low noise performance. Since the noise floor is often pretty high, >> the design of the whole RF chain (e.g. spur levels and such) might have >> assumed that lots of things would be hidden in the grass. > > True, it's one of the many selection criterions for selecting the > instrument that meets your needs. > I've been looking a the luggable HP series 859x and 856x, preferring the > latter because they have a PLL YIG whereas the fist uses a free-running > oscillator. But these machines are old, 80's and 90's, pricey, and not > really > THAT good. Add decent range (up to 9GHz to see recent 5.8GHz devices) and > a > tracking generator and before you know it, you'll be paying $6k or more > for > a 20 year old instrument. > >> If the >> analyzer is of the recent "bring a band of RF down to an IF, sample and >> FFT it for fine resolution" architecture, such things as the number of >> bits in the ADC and the "cleanliness" of the sampling clock might have >> been chosen based upon doing 1024 point transforms being displayed with >> 100dB dynamic range (10dB/div and 10 divisions). > > Most modern instruments do that, at least to some degree. My R&S goes > down > to a RBW of 10Hz by just mixing. Additionally RBWs of 5, 3, 2 and 1Hz are > achieve by additional FFT. This instrument dates from 2001, but I don't > think more recent instruments can achieve a mixing-only RBW of 5Hz or > below. > >> (not to mention the spectrum analyzer actually generating spurious >> signals. I ran across that one last year and thought I had an >> interference source, but, no, went back and checked the spec sheet and >> it said spurious are <-80dBc, and sure enough, there it was at -82 dBc. >> And stories about the first LO coming back out through the input are >> legion.) > > Gee, I wish I had consulted this group BEFORE buying my instrument. I'm > happy with it and I don't regret anything, but you could have added a lot > more arguments in favor or against… > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.