Well, they could be consistent. Most of those photos show only two sizes of helix-type antennas. The larger diameter (probably lower frequency) are quadrifilar helix designs, and they are uniformly "left hand thread" helixes. (I assume that everyone agrees on what a left-hand thread looks like, no matter how they label circular polarization). The more numerous smaller diameter antennas are multi-turn one-element helixes, and they always seem to be "right hand thread" in all of the photos. The smaller antennas are almost certainly for L1.
The complication is the "Block-IIR-M-SV-2S" photo. But it has *three* sizes of antennas visible. The largest are left-hand-thread quadhelix as before, and thus likely close to the same physical dimensions as the large antennas in the other photos. The mid-size ones are multi-element multi-turn helixes that look a lot like the quadhelixes in design except that the ends are left open. And they are about 2/3 the diameter of the quadhelixes, much larger than the simple helix antennas in the previous group, so probably for a different frequency. Then there are the smallest antennas, which appear to be a single-element helix with many many turns - but these are about 1/3 the diameter of the large quadhelixes, and thus *these* are likely the L1 antennas. And, if I look closely, these small helixes do appear to be right-hand-thread wound. Dave On Mon, Jun 4, 2012 at 8:24 PM, Tom Van Baak <t...@leapsecond.com> wrote: > David, > > One of these two photos is correct (odd isn't it)... > http://www.ausairpower.net/Block-IIR-M-SV-1S.jpg > http://www.ausairpower.net/Block-IIR-M-SV-2S.jpg > > Maybe these break the tie: > http://www.spacemankind.com/images/ms/20090817-lockheed-gps-iir-lr.jpg > https://share.sandia.gov/news/resources/releases/2008/images/GPS1.jpg > > http://www.lockheedmartin.com/content/dam/lockheed/data/space/photo/pressrelease/GPS_4A_pr.jpg > http://www.insidegnss.com/auto/popupimage/GPSIIF_photo_lo.jpg > http://www.freepatentsonline.com/6653987-0-large.jpg > > /tvb > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.