Is there some simple utility, or published set of charts, or suite of formulae, where one can approach the situation by inputting a space weather summary, (sunspots, various indexes, etc), the receive frequency (band), half power beam width and gain of antenna, and arc distance from max gain main lobe vector to the sun disk (using the az el of the rotators), where the noise floor will rise enough to make signal detection unlikely, everything else being equal? Yes, that might be too broad a brush. Please educate my ignorance.
Stated differently: If I am working a satellite or the ISS digipeater with a two meter beam or helical, and the sun is up, and the satellite (ISS) pass comes close to or even transits the sun disk, then at what arc distance to the sun (center?) will the sun likely cause enough RFI to black out the attempted communication with the satellite (ISS), on two meter, 70 cm, 23 cm bands? I understand it will depend on the main lobe of the antenna, and its half power beam width? Let's use as an example, the average 3 element yagi maximized for gain, such that it gives about a 40 degree half power beam width... if those numbers are unrealistic, still, you get the idea of what I am looking for, yes? I'd like an announced expectation of a sun causes comm black out. It already says 'eye protection' when the antenna is pointed within 45 degrees arc distance of the sun. Why? When portable, or in power conserving situations, the rotator(s) might be strong-arm, aligning with a big plywood compass (az) rose on the ground, and an elevation scale, while looking somewhat along the antenna. With az and el announcements every four seconds, strong-arm alignment should be plenty good enough. People are making contacts with less accuracy than that, roadside, on youtube.
I'm thinking there must be some utilities already out there without my re-inventing the wheel, for the sun related noise floor increases. Hopefully source code available, opensource, so I can write them into my python script(s), honoring any licensing terms and conditions of course.
My Antenna handbook is from 1988, and I figure there is a lot more data and experimentation since then, particularly in this context.
I've got a python program using pyephem, that runs continuous, and gives periodic voice announcements of the status of upcoming passes and 'in progress' passes, grabbing TLE updates each day, internet connection dependent at least once per week. It runs on a raspberry pi or an android device (since pyephem is easily installed on either of them). I would like it to also give a caution regarding possible noise floor related black out(s) when the pass is closely aligned with the sun (risen of course). For that, I need this additional RFI noise floor based on the sun/space-weather information, so it can be appropriately coded.
Maybe the EME folks have already worked something like this out? The geostationary commercial bird operators know when there is a higher probability for a blackout, briefly, twice per year, when the orbital position basically transits the sun for certain geographic regions. I am looking to know if for the HAM sats, this would only happen if there is a literal transit, or if it develops into happening as the main lobe of the receive antenna gets within a certain threshold arc distance of the sun.
Comments please if you need more clarification.
I have selected the post from tomnexus as the answer, but I wish to be clear. Phil Frost - W8II 's post was just as valuable as the answer. As is often the case here, there is not always a best answer, but instead, several postings that form the more complete answer for which an OP was hoping. Some of the comments and comment exchanges were also essential toward an answer that would give me what I need to form a project decision. If you can, imagine that both these posts have been selected as the answer. If there are more posts that I miss later on, I trust they will be in some way helpful to someone with a similar question(s). Thank you to all the contributors.