Hi Joe and the group. IMHO when we get to discussing IGRF for mounting an antenna and rotator for amateur radio use, we are over thinking this issue. Now I must admit that I only have a 3 degree difference in EN19 which I completely ignore. I find there is too much magnetic QRM around here to get a good reading of MN and then correct for TN. The more sensitive the compass the harder to get a bearing. Well you get a bearing, but you know its dead wrong because you get a different reading my moving a few feet in any direction. So, unless you use the super desensitized 1/2" diameter compass on a Captain Canada Decoder Ring I find Google Earth pragmatically good enough.
Software such as SatPC32 and others allow you to make permanent corrections for AZ and EL changes or compensation for mounting the antenna a little off horizontal and true north, or changes that occur over time. A little slippage in any of the half dozen U-Bolts between the terra firma and the antenna beam during a windstorm can be corrected - U-bolts on the mast to rotator, rotator to boom, boom to the antenna saddle, the saddle to the beam. It's a wonder anything stays pointing to where you want it. However, to contradict myself, I have been known, on occasion, to sight along the beam of my yagis to the Sun and use any number of the freeware Sun locator applications. Very handy on Field Days in remote locations. I've never found the Sun's RF useful for aligning antennas mainly because I've never heard the difference on UHF/VHF or S band even with preamps, but, maybe that hearing loss due to age :-) 73, Alan VE4YZ EN19kv AMSAT LM 2352 http://www.wincube.ca > Hey everyone at the amtat-bb! > > I spent a good portion of the day sick in bed yesterday and only > naturally got to thinking about quite a few things. I figured i'd pop > on here and start asking questions. Here's some background > information on my sat experience; my rig consists of a TH-F6A > (handheld, not full-duplex) and an arrow antenna. I have been > successfull at manually trakcing the ISS and AO-51, but I have been > unsuccessful at making a contact. I went out to field day (in Oviedo > Florida) and was able to check out the rig the LMARS club uses. This > got me wondering about sat tracking software, the internals and what > definition of "North" that is used. > > I'm familiar with the IGRF (from my day job as a GIS guy) and was > wondering if any of these apps use the IGRF for calculating magnetic > declination: > http://www.ngdc.noaa.gov/IAGA/vmod/igrf.html > > I've thought about creating my own rotator and started wondering about > the configuration used. When you buy a rotator and put it out in the > yard, i'm guessing you have to orient the base 'correctly'. How is > the base of a rotator usually aligned? Do you get a compass out and > use local magnetic north (without compensating for the declination > from the IGRF). > > I'm still in learning mode and very new to the world of sat, so if > these are really dumb questions, my apologies! > > I am open to any reading materials you can suggest on the matter. > > Joseph Armrbuster, KJ4JIO > _______________________________________________ > Sent via amsat...@amsat.org. Opinions expressed are those of the > author. > Not an AMSAT-NA member? Join now to support the amateur satellite > program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via amsat...@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
