Hi, David and Group.
On Thu, 19 Sep 2002 G0MRF@aol.com wrote:
My conclusion: The original estimate is too high and my estimate is probably
too low and the only sure way is to spend some time measuring.
Your conclusion may be right. But I say "if antenna curent is 1 A..." and
so on. Large resistance should decrease antenna curent and ERP should be
much lower. This is why one need measure antenna curent to estimate ERP.
Output TX power is not adeqate info.
Also, it is worth to take into consideration Giulio's relatively high
antenna (60 m!!!) Whithout top load this yeld 30 meters of effective
height. If there is very large top load then ERP should be 4 times grater!
If antenna height is 10 m (for example) then ERP is 9 times lower...
ERP is mainly determed by antenna current and efffective height. If this
is known then it is very simple to estimate radiated power. Certanly this
is very aproximative estimation. But something is better then nothing :-)
73 de RA9MB/Alex
http://www.qsl.net/ra9mb
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