[Ground-station] Link budget

[Michelle Thompson]

Salvatore and Alan,

I see the spreadsheet in the cloud instance, and am looking forward to
hearing how this translates into Python.

A tricky part of this is the required propa.dll. The ITU Rain Model in the
spreadsheet uses macros. Some of these macros make use of a database, which
computes rain, atmospheric and scintillation losses. This information is in
a system file called propa.dll.

I put the propa.dll in the repository with the spreadsheet here:

https://github.com/phase4ground/documents/tree/master/Engineering/Link_Budget

Here's instructions from Jan King:

"You put this file into your WINDOWS10 machine (this thing won't work on a
Mac) operating folder using the procedures in the Word file (also
attached). Then reboot the machine; then install and open the Excel Link
Model attached.  When you open this Excel as it is a .xlsm type file, it is
suitable for using macros.  When you open the file it will prompt you by
asking if you want to enable the macros.  Say YES."

At that point the rain models work.

We have two choices here. We can set the ITU Rain Model aside for now. Or,
we can commit to converting the entire thing.

"Working code is better than complete documentation". My goal here is to
get working code, quickly. Then, review and evaluate. Setting aside the ITU
Rain model for now and getting the rest done first is not a bad approach to
start out.

We do have to consider rain fade at the frequencies we are looking out.
However, there is still a substantial amount of utility without the ITU
Rain Model, and we are smart enough to understand the effect on margin.

This is a substantial landmark spreadsheet. It will continue to be used,
and to be useful, in its current form. This discussion is not an insult to
the spreadsheet or anything like that.

It will involve some effort to port to Python (Jupyter Notebook), but many
hands make light work. The benefits of this work being in a Jupyter
Notebook are numerous. The first one is that it eliminates the restrictions
incurred by having to use propa.dll and Windows. The second is that there's
every expectation that fixing bugs and testing this budget will become a
*lot* easier. This work is well worth doing and appreciated.

-Michelle W5NYV




On Tue, Jan 19, 2021 at 11:12 AM Michelle Thompson <
mountain.michelle at gmail.com> wrote:

> Thank you very much Salvatore,
>
> There is no Octave code base that I know of, but this is a very good
> direction.
>
> -Michelle W5NYV
>
>
>
>
> On Sun, Jan 17, 2021 at 8:31 AM Salvatore Lionetti via Ground-Station
> <ground-station at lists.openresearch.institute> wrote:
>
>> Hi guys,
>>
>> I'm sorry but I've started yesterday to work on this topic.
>>
>> I've made the spreadsheet available on my personal Nextcloud web instance:
>>
>> https://cumlaborare.strangled.net/s/Ng5H3RmmZP8HzNE
>>
>> By this way:
>> * multiple people can collaborate on the same document, at the same
>> moment.
>> * comments are allowed,
>> * versioning is in force.
>>
>> I've setup no password for now, but content can be recovered from a
>> previous version very easily. (similar to Wikipedia)
>>
>> In the meanwhile I've verified that Jupyter can also use Octave
>> interpreter, giving us the possibility to have a single code base.
>>
>> Is there a (also partial) Octave code base to reuse?
>>
>> Have a good day
>>
>
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