Topband: Short Radials / Antenna Update
gswynar at durham.net
Sun Oct 29 07:39:43 EST 2006
Good Day All,
Results with the "...interim" 2-element 135-degree phased inverted "L" array here are DEFINITELY getting interesting...!
I re-wired the rat's nest maze of wires that is the manual antenna direction switch box on Friday (don't even ask), and in the lull moments of this weekend's CQ WW SSB contest, managed to convince a few of the participants to give me some feedback as to its (possible) directional capabilities...
It seems that the further away the station is, the more pronounced the effect, to whit:
-Several hundred miles north of me, the difference between my beaming east, west, or omni-directional (both elements in phase) was only "...marginal";
-Several hundred miles south-west of me (Ohio), the western and omni-directional settings were similar, but the easterly direction saw my signal drop some 10 db.;
-About 400 miles west of me (Michigan), the eastern direction saw my signal strength drop "...in half". The omni-directional pattern was stronger, but when beaming west the signal was by far the strongest, and,
-Further away, in the mid-west (9-land), the east-west difference was the biggest, at 20 db. in favour of the array beaming west.
I realize propagation vaguaries play a huge role in all this, but there is definitely something good happening here. More testing is in order, of course --- it sure would have been nice, though, to be able to run some "A-B-C" comparisons with a few of the guys in 6-, or 7-land...
The total radial count here, per "L", remains at 16 EACH, all 1/8-wave long --- this is in keeping with the excellent write-up on ground radials referenced in pages 3-9 to 3-10 (and Table 1 on page 3-10) of the 20th (newest) edition of the ARRL ANTENNA HANDBOOK. An interesting observation, if you happen to have a copy of this book in front of you: do I understand it correctly that the table therein establishes that the difference in low-angle radiation between a "minimum" radial system like mine, and a "maximized" system with fully 120 radials --- and each 0.4-wavelength long --- is a mere 3 db....?
If so, that translates to but a HALF of an S-unit at the receiving end!
What am I missing here?
It certainly lead me to believe that there is, indeed, hope for guys like yours truly, who might otherwise be intimidated into trying something just a little more competitive on 160 that's perhaps beyond the "...usual fare", in the absence of the proverbial miles and miles (or kilometers, if you're in "VE"-land!) of copper wire...
~73~ Eddy VE3CUI - VE3XZ
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