Hi, Giulio and Group
On Mon, 26 Aug 2002, Giulio Scaroni wrote:
I have made some comparisasion tests on my RX antennas at the beacon lower
power level, the winner is again the AMRAD E field antenna, with many db
of better S/N then my ferrite antenna, so this week end i'll try to do a
separate ground connection for the antenna, for see if there will be some
improvement in S/N.
Some years ago I had estimate sensetivity of ferrite antenna theoreticaly.
I found it is not so good. For good sensetivity one should use ferrite rod
about 5 or 10 cantimiters in diameter (and about 1 meter long)! Simple
loop about 1 - 2 meter in diameter is much better!
For E-field antenna it can be good to use few radials, not ground. And use
ferrite transformer to avoid noise transfer from external surface of coax
to antenna. Some my experiments show this.
About Vlad is good results that him listen my beacon, i think that the my
ERP is not so high, only 40 W with 60 meters quasi vertical 2 mm CU
wire,no long radials, and poor earth location on a rocky mountain at 1000
meters on sea level, so if him listem me in aural CW, in QRSS may listen all
Europe, from CT to LY, good news.
May someone calculate the beacon ERP???
For ERP calculation antenna curent is needed. I think Your curent is about
1 A (if loss resistanse is 40 Ohm). And if there is no top load in this
case radiated power is about 0.3 W.
73 de RA9MB/Alex
http://www.qsl.net/ra9mb
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