SRTM - Shuttle Radar Topographic Mission - THey built a precision interferometric Synthetic Aperture Radar that mounted in the shuttle's cargo bay and had a 60m(?) boom sticking out, with precision m
You've just seen a parade of people confirming the general usefulness of this application and the fact that there isn't ANYTHING else out there that even tries to do what it does, and you think it's
Original USGS DEM files were created from topographic maps. The 3 arcsecond 1x1 degree squares I have were created from USGS 1:250,000 scale topo maps (which cover 1x2 degrees). They basically turned
I said or meant to say that the HFTA program is a good idea (in fact I think that it is a great idea) but extracting the data to use the HFTA is difficult to do and is a half baked process. 73 Mark N
Yes, because HFTA doesn't do any calculations for "sideways" propagation. It models the surface as a set of plates that don't slope left or right. Jim Breakall (W3FET, I believe) and his colleagues d
Yes, yes indeed.. and the fact that the source of the raw terrain data keeps changing the interface doesn't make it any easier. Just give me a simple backend like FTP with a decent naming convention
Kudo's and many thanks to Steve for DEM files for my QTH. As others mentioned, the Microdem/DEM web site is impossible - gratuitous GUI violence by the site owner makes no edition of published instru
Yes, making use of HFTA can still be a PITA, but the development is still in relative infancy. Remember when Jim Lawson / W2PV did his early yagi analysis work on a one off basis on big GE computers,
The database method will produce a table with rounded, uniform numbers in the distance column and interpolated heights; but when using a local topographic map it's probably easier to do it a differen
Perhaps one day an HFTA "wizard" can be developed where the program simply inputs geographical coordinates from the user, searches the geography based on the USGS database, compiles the radial inform
Yep, the "inches" was a bit of a stretch but at my QTH (on edge of a steep 225' hill and with nearby 100' "lumpy" hills) by using the program to move the tower location around -- toward/away from the
Did you study the discussion of HFTA, and of the technical concepts upon which it is based, in the ARRL Antenna Book? Because I did that, I thought it was pretty good, and I sure don't think it's "ha
The modeling part is fully baked. The terrain retrieval process is raw and uncooked. I was thinking, though.. The entire US, with 3arcsecond precision, easily fits on 5 600MB CDROMs in a not very com