Grape setup questions

[Ariel Blum]

 Hi,

I finally got my Grape plugged in about a week ago and have been collecting data since. I’m not sure if my data is good because when I compare the plots to what I’m seeing in the group, there doesn’t seem to be much frequency variation at all. I’ve attached two data plots and a screenshot from the Pi.

Also, I’ve been unplugging it and moving it around to try and figure out where I’m going to leave it permanently and I’ve noticed that on the days when the power has been interrupted, there’s both a .csv file and a csv.bad file. Does that mean that the data from that day isn’t usable? Would it be worth it to try and hook it up to the battery backup for the server that my father maintains?

Also, I’m currently using a Pi 4 but it would be preferable to be able to run the Grape on a Pi 3B (not +). Would that be possible?

Thanks,

Ariel VE2SZU

[Randy Allen]

Welcome, Ariel,

The plot from 12-17 looks pretty typical for the eastern part of the continent for 15 MHz WWV.  That huge dropout (first half of the plot) is typical for no signal from WWV on 15MHz.  The plot of 12-20 might be OK, too, because of the Solar flare we've had around then.  15 MHz was not usable at all for a period of time around 12-20 as your plot shows.

One thing I notice that is not normal is that you do not have your Node Number entered and I wonder if your data will be uploaded at the proper time.  Our node numbers tell the Grape system when to upload our data.  My numbers are 53, 58, and 78 and that means my data from each of the 3 stations is upoaded at that many minutes past midnight UTC.  My first station uploads at 00:53 UTC, the second uploads at 00:58 and the last one uploads at 01:18 UTC.

John Gibbons should have sent you a node number when you registered your station.  Find that node number and make sure you have your data in the uploads configuration file set correctly.

In your location, 15 MHz will be of little use.  10 MHz will yield much more usable data.

Oh, and Ive not seen the power interruptions you speak of...the BAD.csv file...Jus never noticed it.  My systems recover from power interruptions regularly with no ill effects  (thus far...holding my breath).

let me know if I can assist further.

73, N4TVC, Randy

Happy holidays.

[Randy Allen]

OH, and I forgot one of your questions...the RPi 3B (not +)...I ran for an extended period of time (months) on a RPi 3B+ with no ill effects.

Give it a try AFTER you get the other variables solved.

73, N4TVC, Randy

[Kristina Collins]

Hi Ariel, 

Thanks for reaching out! We are very glad to have you join the network. 

If you don't yet have a node number, please see Step 64/65 in the edited instructions at this link: https://zenodo.org/record/8307367/files/MakeGrape1OSImageV1_04.pdf

This explains how to generate a file with the requisite information to obtain a node number. If you run into any roadblocks, please send questions to the Grape list.

I'm attaching the plots for the dates you sent for comparison. (Busy space wx days.) I echo everything Randy said above. Your received power might be a little on the low side.

73,

-KC

--
You received this message because you are subscribed to the Google Groups "hamsci-grape" group.
To unsubscribe from this group and stop receiving emails from it, send an email to hamsci-grape...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/hamsci-grape/5b0d8c74-bde4-401f-925e-a24804d6c7cen%40googlegroups.com.

[Randy Allen]

Ariel, Kristina, All,

Kristina has a good idea to compare with these combined plots from several of our stations on the 17th and 20th.  I would caution, though, that most of these plots are from 10MHz stations, not 15MHz stations like yours.  The bottom 2 in the legend are 15 MHz stations (one is mine).

To make apples-to-apples comparisons, I've attached my 15MHz plots for those 2 days so you can do a direct comparison in addition to the combined plots Kristina provided.

I agree with Kristina that your signal strengths look weak.  Mine are not all that strong, either, but that's mostly the 15MHz propagation this far east.  I'm on the east coast near Washington DC.  FM18is.  I have good 10MHz signals most of the day, but 15MHz just isn't that great.  You can see the same dead areas in my plots as yours, between Midnight UTC until local sunrise in the middle of the plots.

The black trace spikes in your plots are indeed Doppler frequency shifts.  Note the local sunrise (about 11-12 UTC here, for me) spikes.  so even at 15MHz it is obvious.

Thanks for helping with the explanations, Kristina.

73, N4TVC, Randy