I'm pleased to launch the RabbitEars Search Map into public beta. I mentioned in my previous site update that I wanted to do it, but it stuck in my head and I decided to buckle down, dedicate most of my evenings and weekends to it. It's paid off, and I think it will work out really well.
So here's where to go see it: https://www.rabbitears.info/searchm...
It gives multiple means of choosing a location, the results have a handy link to a page that anonymizes the results, it's a ton faster than the existing search code, and there are nifty maps and diagrams to help understand what is going on in specific situations. Please feel free to provide as much feedback, good and bad, as possible. I want to know what I got right and what I got wrong. If I got things wrong, I can probably adjust them.
Beyond that, there are a few things I want to note about it.
First, if you have questions, please be sure to read the instructions. If they're not clear and/or don't answer your question, please let me know. I want them to hold the answers to all the questions people have, if possible.
Second, the terrain path profiles remain under construction. If at some point you look at it and it looks wrong or doesn't work, wait a few minutes and try again. I'm probably working on it. If it lasts a long time, let me know as I may not have noticed that I broke it, or you may have found a corner case that I need to investigate. But the key thing I'm still working on is trying to make it possible to either adjust the height of the display or, preferably, automate the resizing of the height. It's proving more difficult than I expected, and I decided not to hold the release of the whole tool over that one item.
Third, unlike other things on the site, the underlying database is a snapshot of the RabbitEars database as computed each morning. This was done to help speed things along; by dumping the database once into a simplified format, rather than having to parse all the LMS tables each time a search is run, the speed was drastically improved. Additionally, in the interest of consistency, these rows are stored along with the results for a study, so the information in the result link should remain consistent even if the database changes. The only exception is the repack data column; that is tied to live data because it may provide an insight into what's going on for someone who is confused about the current status of things.
Fourth... I feel like I'm forgetting something. I may update this post in the next few days if I think of more comments I wanted to make.
Finally, I'd like some people to check behind me on some of the math. I'm reasonably confident in it, but having additional eyes on it would make me feel a whole lot better. There are three things, specifically, that I am concerned about.
1) The formula for converting from dBuV/m to dBmV in the unit conversions. (The dBmV is then converted to either dBm or dBuV if necessary--those conversions are fine.) I derived the formula from two other formulas with common elements, but I'm not entirely certain I applied them correctly or even that my result makes sense. I don't do a lot of these types of conversions. My end result was:
20 * LOG10 ( ( POW ( 10, ( s.field / 20 ) ) / ( .021 * s.freq ) ) / 1000 )
Where s.field is the field strength in dBuV/m, and s.freq is the center frequency of the station in question. If someone has a different formula that is more correct, please let me know.
2) The formula for earth bulge as used in the terrain path profiles. I already changed it once.
( ( 1000 ) * ( 1 / ( 2 * 6370 ) ) * ( $dist * ( $terrain_len - $dist ) ) ) / ( 4 / 3 )
Where $dist is the distance from the beginning of the profile, and $terrain_len is the total length of the profile.
3) Also in the terrain path profile, I'm a bit concerned that I am oversimplifying the geometry. I'm just applying the earth bulge formula to the terrain path profile and that's it. Does anyone think it makes a significant difference whether or not I factor in the full geometry at the transmit and receive ends, or is this good enough?