Re: NEC-LIST: More on the CFA

Dear all, interested in CFA

First of all, I'm interested in the cfa modelling and I have already
shared with many of you my first model (done with EZNEC-nec2 only).
At that time I had already found the strange behaviour of the antenna
in changing the source from current to voltage, but with maybe an
excess of caution I did not mention this results. Instead I raised
some question on voltage VS. current source on this kind of antenna
but I never get answer. So with a friend I started to build a
professional (for what is possible to our capability) CFA antenna for
80 meter lambda (the design is done according the Antennex
pubblication). Yesterday evening (this work is done for hobby) we
verify with very low power (about 10 mW) the input vswr and the
correctiness of phase relationship between the D plate and E
cilynder). In the next few day (maybe today) we should start some
test with 100 watt power in order to see if there are problem in the
matching section (arcing or overheating of components). I'm afraid not
having the capability to setting up a calorimeter set-up on the
matching component, this could be a good starting point to measure the
losses in the matching unit. Then we plan some non quantitative on
the air test : just try to obtain some listening report in the 80
meter band with A-B switch between a long wire antenna and the CFA.I
think we could settle some skedule with those of you who are
radioamateur ...

In the next future we plan to build a scaled version of the CFA (
around 150MHz) and put in on a reference site (compliant to CISPR 16
NSA) : semi anechoic chamber or OATS. and measure some cut of the
radiation diagram. Anyone who wish could help in providing the scaled
version of matching unit and geometrical dimension.

I will share the result here

regard

Giuseppe Rossi
  
Received on Thu Apr 22 1999 - 17:41:56 EDT