4. ) SUBJECT : SURGE SUPRESSOR PLACEMENT
Question :
in an installation with IDU-ODU linked with an IF cable using 2 surge arrestors. One next to the oDU and another at the building entry plate, what is the Surge arrestor next to the ODU protecting? ODU or IDU?
Answer :
very late reply, but just in case you still have a problem.... The sign on a surge unit named "Protected" means that on this port you have to connect the unit you are trying to protect. So, in your case, where the surge protector is installed at the ODU side, the protected port has to be connected to the ODU. Look: If the lightning strike will hit directly to the ODU, there is no hope for the ODU anymore. The strike will continue to go towards the IDU and the surge protector on the building/shelter entry point will have a job to eliminate the strike. If the lightning strike hits the tower, there is a large posibility some of the power will be inducted to the IF cable...in that case, both surge protectors will try to eliminate the strike ( entry point for the IDU, near the ODU for the UDU). Luckily, the strike hits the top of the tower and not directly the MW ODU equipment.
BUT.... there are always different kind of thinking....when the lightning stikes are on the menu :)
5. ) SUBJECT : PLANET TERRAIN DATA PROJECTION ON PLW4.0
Question :
really need your help on pathloss.
Actually the problem is this:
I'll like to make use of your "MSI PLANET Terrain Data UTM Projection" aspect of pathloss but I'm having some problems using it. We'll(our company- Huawei Tecnologies) like to use this aspect of pathloss because we believe it would give us a more accurate Terrain Database. However my major problem is that pathloss doesn't accept my index file and i don't feel there is any problems with it(Nigeria 1117744.642 -227668.6368 458077.6182 1530357.619 50). I tried other ways like using the utm zone for Nigeria (32N) but at the end of it all it won't create a background for the map (so I'm not sure it accepted it).
The question is:
How do I work with Pathloss with a specified geographic frame like that as shown in the index file attached (instead of the frame of the whole world).
Answer :
You need to know the UTM zone number. This is not specified in the index file. Somewhere there is a projection file (prj). The zone will be in this file.
I imported the index.txt file into the list; however the east and west edges were reversed.
When you are in the Import List - Define Fields dialog box, first click the Planet button and then set the west edge to 3 and the east edge to 2. Alternately you can just change the values directly in the grid display.
The following link provides details of the planet database as used in the Pathloss program
ftp://www.pathloss.com/pub/docs/planet_utm.pdf
6. ) SUBJECT : SRTM 3 ARC SECONDS
Question :
I have a problem on using the SRTM 3 arc seconds dataset. I have bought some CDs including the SRTM dataset, but I can not use these datasets, all the configuration are ok per the pathloss procedure. on the CDs, there are 5 files for each 1x1 degree tiles, which named NxxExxx.bil,.....etc. I wonder what's the problem.
anybody can help me on this issue?
Answer :
have a problem like you when I got SRTM Dataset.
In the SRTM Dataset CDs have only 5 Files but in pathloss web page state that should be 10 Files for using with pathloss.
In SRTM Dataset CDs compose of *.BIL, *.BLW, *.HDR, *.PRJ and *.STX and the another 5 file is not appear in CDs.
If we got the another 5 file may be pathloss tool can work.
Anybody can help me? Where we can find the remaining file?
METADATA.DBF
METADATA.PRJ
METADATA.SHP
METADATA.SHX
METADATA.TEX
Thank you in advand for your support.
Answer :
Hello,
I found a way around this problem.
The Srtm .bil files are in little endian order ie.. the least significant byte is stored first and the Most Significant Byte is stored second for each Two Byte integer in the .bil file. Pathloss 4 requires it to be in Big endian (or Motorola) order, where the MSB is stored first and LSB is stored second.
The .bil files in the CD therefore have to be converted into big endian order. I have written a small Visual basic program which can do this. Perhaps you can do the same at your end! Otherwise get in touch with me at bnncomm@ndb.vsnl.net.in
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