When I was working at the Arecibo Observatory and we were running the ionospheric heater at 5.1 MHz (think Mini-HAARP), I'd sometimes go home (about 3 miles away) and listen to the signal there. There was frequently substantial random fading of the signal, suggesting that I was hearing the vector sum of an NVIS signal off the ionosphere and the usual sidelobe leakage from the dish. Said fading could be said to have a characteristic period of around 1 or 2 seconds, and was occasionally quite deep.
So, I'm definitely a believer in short path propagation variations. Dana K8YUM On Fri, May 11, 2018 at 1:09 PM, Bob kb8tq <[email protected]> wrote: > Hi > > Well, having actually run FMT virtually “in the back yard” of the > transmitting station …. it’s surprising > what 70 miles will do. In this case, back yard really does mean on the > premises. There is a lot that > gets into even fairly sort distance propagation. > > Bob > > > On May 11, 2018, at 1:52 PM, Jerry Hancock <[email protected]> wrote: > > > > If you were in Connie’s back yard or had a very stable ground wave, then > yes, you could automate the testing. > > > > There are a number of challenges with this method as looking at the data > with a simple graph will tell. You might have large fluctuations on the > high frequency side only, for instance, that any averaging or algorithm > would assume to be valid data. > > > > The next issue is the length of the dataset as the key-down time is only > a few minutes so you end-up with not that many samples. > > > > Regards, > > > > Jerry > > > >> On May 10, 2018, at 5:59 AM, Don Murray via time-nuts < > [email protected]> wrote: > >> > >> Hi Magnus... > >> > >> > >> Appreciate any help! > >> > >> I participate in the ARRL Frequency Measuring Test, > >> and I would like to automate the measuring process. > >> > >> I have two frequencies, A and B... > >> > >> A is a GPS locked HP 3336B set to 455,000.000 Hz > >> > >> I use the 3336B instead of the 455,000Hz BFO > >> signal from my GPS locked Racal receiver so > >> that I can measure AM stations without the > >> annoying beat note. ;-) > >> > >> B is an IF signal which should appear between > >> 455,000.000Hz and 455,001.000 Hz > >> > >> I would like the 5372A to calculate the B minus A > >> delta, over a manually started and automatically > >> stopped measurement period of 110 seconds. > >> > >> I would like a delta resolution of 0.001Hz to be > >> developed by the box. > >> > >> Now, there will be doppler. I want the box > >> to analyze and give me a best statistical guess > >> for the B minus A delta. > >> > >> BTW the B minus A delta will be added to the > >> frequency of my Racal receiver to give me the > >> best "guess" as to the correct frequency of the > >> target signal. > >> > >> The Racal reads out to the Hz, and I am able to > >> accurately determine if the Racal is tuned above > >> or below the "target" frequency. > >> > >> I will be tuned below the "target" and within > >> 1 Hz of the "target." > >> > >> I assume I will be in the one frequency mode. > >> > >> Can the box give me the desired resolution? > >> > >> What sampling period would be the best to use? > >> > >> What statistical result would I use as my delta? > >> > >> Appreciate your help. My head is spinning whenever I > >> get into the operating manual! > >> > >> TNX... > >> > >> > >> 73 > >> Don > >> W4WJ > >> > >> In a message dated 5/10/2018 2:19:49 AM Central Standard Time, > [email protected] writes: > >> > >> > >> Hi, > >> > >> What issues do you have? > >> > >> Cheers, > >> Magnus > >> > >> On 05/08/2018 02:32 AM, Don Murray via time-nuts wrote: > >>> Hello Time Nuts... > >>> > >>> > >>> > >>> Who is the resident expert on the HP5372A? > >>> > >>> I have some operational questions. ;-) > >>> > >>> email off list please. w4wj at aol.com > >>> > >>> TNX all... > >>> > >>> 73 > >>> Don > >>> W4WJ > >>> > >>> > >>> _______________________________________________ > >>> 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. > >> _______________________________________________ > >> 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. > > _______________________________________________ > 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.
