On Saturday, August 07, 2010 05:14:52 pm Bob Goodwin did opine: > On 07/08/10 16:00, g wrote: > > then, start out with a reflector plane and graduate up to a helix. > > > > i have built 'cantenna', 'log periodic', and 'helix' for amateur radio > > microwave, and wifi, with good to excellent results for both. > > > > have fun. > > G, I have antennas all over, but these two boxes I am messing with > have no connectors. Not only that but cable losses are very high at > these frequencies and more than a few inches of cable will cost you > more in loss than you can gain with directivity. 5 gHz probably > wants wave guide ... > > Bob Absolutely Bob. About the practical Maximum Usable Frequency of coax is in the 2.2 Ghz range, and that is for 1.625 inch heliax or better yet, rigid. About $7 to $12/foot, used. I have used smaller stuff, but at 1.5Ghz ranges, with buckets of powered gain on the sending end, it can make it 300 feet still strong enough to drive a 950-1450mhz satellite receiver over quad shielded RG11. Those teeny little cables they put on so-called 7DBI antennas actually have a loss of several DB/meter. I have one of those, tested at about + 0.5 DB over the cards rubber ducky at its best placement. Needless to say, any connectivity I have in the attached workshop, separated from here by 3 walls, one of which still has the alu house siding on it, is by way of a 150 foot cat5 cable to the outbuilding my cnc mill is in, thru a 100base-t hub out there, and another 100 foot of cat5 across the yard and in a side window of the garage. PIMA, but it works. That first 150 footer has been strung overhead, swinging in the wind for at least 6 years now, and in fact survived a wind on June 24 that took down 3 of the 5 mature trees on my property, and measured 112 mph on a recording anemometer about a block away, downwind. I am amazed that a common piece of Belden blue cat5, right out of a 1000' box, is still working, but it is. [root@coyote linux-2.6.35.1]# ping shop PING shop.coyote.den (192.168.71.4) 56(84) bytes of data. 64 bytes from shop.coyote.den (192.168.71.4): icmp_seq=1 ttl=64 time=1.76 ms 64 bytes from shop.coyote.den (192.168.71.4): icmp_seq=2 ttl=64 time=0.142 ms 64 bytes from shop.coyote.den (192.168.71.4): icmp_seq=3 ttl=64 time=0.140 ms -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) He is now rising from affluence to poverty. -- Mark Twain -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
