Post by killy on Jun 7, 2016 19:32:32 GMT -5
Been fairly quiet on the board since late 2011 with the phased loops. They have been and still provide outstanding perf. on 80m cw. Only problem is the multiple ice storms, now occuring several times from dec tru april; must keep in shape just to keep them up!
Since this array is providing so much fun, i'm now adding a 4 phased inverted vee for 80m ssb use, again on a 1/4wave between elements; so this array will require only 210feet of "virtual boom", vs the 300 feet for the loops.
The VNA 2180 provides these extra accurate ant. measurements, required for proper phasing network calculations.
This time however, i wont have to reinvent the "wheel" of phasing calculations, and will be using the .XLS spreadsheets i developped for the loops.
Only problem now (and was having similar challenges with the loops), is with the snow melting and the ground barely thawed out, keeps the readings of Z and mutual Z changing on a daily basis, since the elements are seeing the ground further away as it dries up.
Am seeing changes of 1kc/foot of ground level variation on some elements, also affected with the rain wetting the earth.
Interestingly, elements 1 and 3 are over solid granit, with 2 and 4 over mostly earth; these last two are showing more variations than the first two.
So you can imagine the wild readings when measuring the mutuals!
Have previously seen these variations on the loops, requiring totally separate phasing networks for summer and winter; the winter networks are totally useless in the summer and vice-versa. Luckily, this mountain top forces me to quit operating during thunder season, giving me time to maintain this wire farm! The winter snow cover from dec tru april has shown very stable ant. impedances and consistent phasing angles/currents.
So will try to put an update of how this thing goes as it stabilizes, in case anyone is interested.
roy va2gu
Since this array is providing so much fun, i'm now adding a 4 phased inverted vee for 80m ssb use, again on a 1/4wave between elements; so this array will require only 210feet of "virtual boom", vs the 300 feet for the loops.
The VNA 2180 provides these extra accurate ant. measurements, required for proper phasing network calculations.
This time however, i wont have to reinvent the "wheel" of phasing calculations, and will be using the .XLS spreadsheets i developped for the loops.
Only problem now (and was having similar challenges with the loops), is with the snow melting and the ground barely thawed out, keeps the readings of Z and mutual Z changing on a daily basis, since the elements are seeing the ground further away as it dries up.
Am seeing changes of 1kc/foot of ground level variation on some elements, also affected with the rain wetting the earth.
Interestingly, elements 1 and 3 are over solid granit, with 2 and 4 over mostly earth; these last two are showing more variations than the first two.
So you can imagine the wild readings when measuring the mutuals!
Have previously seen these variations on the loops, requiring totally separate phasing networks for summer and winter; the winter networks are totally useless in the summer and vice-versa. Luckily, this mountain top forces me to quit operating during thunder season, giving me time to maintain this wire farm! The winter snow cover from dec tru april has shown very stable ant. impedances and consistent phasing angles/currents.
So will try to put an update of how this thing goes as it stabilizes, in case anyone is interested.
roy va2gu