Hi If it's a "reasonably priced" synthesized radio, -90 is probably better than anything you will find on VHF at 100 Hz offset. A lot of stuff out there is closer to -60 than it is to -100. 100 Hz doesn't mess up the adjacent channel rejection, so they don't worry a lot about it.
Bob On Sep 19, 2010, at 12:04 PM, francesco messineo wrote: > On 9/19/10, Magnus Danielson <[email protected]> wrote: >> Frank, >> >> On 09/19/2010 09:35 AM, francesco messineo wrote: >>> Hi >>> >>> On 9/19/10, Bob Camp<[email protected]> wrote: >>>> Hi >>>> >>>> Is -195 dbc/Hz floor good enough or is it overkill? >>> >>> I'd say this is obviously overkill, -160 dBc/Hz could be a good >>> compromise. >>> >>>> >>>> Is -155 dbc/Hz at 100 Hz offset a requirement or is -40 dbc ok? >>> >>> -40 dBc/Hz at 100 Hz is about useless, -150 dBc/Hz at 100 Hz is again >>> a good compromise, the lower (practically) the better. >> >> Do you *really* need -150 dBc/Hz? That is a hard requirement! >> >>> It's hard to explain why to ones not familiar with weak signal >>> operation between broadcasting signals, but really the noise floor >>> raise a lot when you have some 5 or 6 broadcasts signals in 500 KHz of >>> band (all with power levels of at least 10 dB more than the levels >>> used in amateur radio, often +20 dB more) >> >> I would need some more fundamental understanding of the system and needs >> to be able to understand how you come up with the above noise level at >> 100 Hz. > > as I said, if it's not possible or not practical, of course I'll take > what I can get. The receiver will be limited by its phase noise and > not for example by its IMD3. > I think already -110 dBc/Hz at 100 Hz is better than any LO in > commercial receivers (for ham radio at least). > > Best regards > Frank > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
