"tzitzikas" wrote in message
...

i have an 500w medium waves transmitter (output 50ohm) at 1431khz. i
have the components and i have decide to construct this
http://www.tzitzikas.webs.com/match.JPG match system. it is ok? i must
connect the power/swr meter before this system (between transmitter and
match system) or after this system (between match system and antenna)?
my antenna is an inverted L 5l/16 antenna.
do you have to propose any better system? thank you

--
tzitzikas


Are you allowed to operate a 500 watt transmitter in the medium wave band in
your country for student radio? That sounds a lot of power to cover a
campus.

What is a 51/16 antenna? ... is that 3.19 wavelengths long? ... if so, that
would be inefficient as a medium wave radiator.

You'll find that a pi network, as you propose, can be made to match almost
anything to anything at a spot frequency, as long as the L and Cs have
sufficient range, but you might have difficulty achieving adequate
uniformity over the nominal 9 kHz bandwidth of a normal medium-wave
transmission (i.e. a broadcast service).

Chris

my antenna is (5 x wavelength) / 16 . it is ok or i must modificate it to wavelength/4??? the horizontal part is about 45 meters and the vertical is about 20 meters.

"tzitzikas" wrote in message
...

my antenna is (5 x wavelength) / 16 . it is ok or i must modificate it
to wavelength/4??? the horizontal part is about 45 meters and the
vertical is about 20 meters.

--
tzitzikas


If the wavelength is 209.6 m then those dimensions sound like 0.21 and 0.1
of a wavelength so now I understand: the total length is 5/16 of a
wavelength, not 51/16 as you wrote before.

Why don't you make use of the programs Ian Jackson offered, for educational
purposes as he put it.

If this is pirate radio then you probably don't care about the audio
quality, so there's no point in me banging on about keeping the Q of the
system low.

Chris

On 30 sep, 19:11, tzitzikas wrote:
my antenna is (5 x wavelength) / 16 . it is ok or i must modificate it
to wavelength/4??? the horizontal part is about 45 meters and the
vertical is about 20 meters.

--
tzitzikas

Hello,

It can or cannot. It depends on your required coverage area, soil
characteristics and ground network. Assuming local coverage, it will
definitely work less then a vertical quarter or half wave fed over a
very good ground network.

When you have a relative bad ground circuit, you may only need a
capacitor in series with the antenna wire to do the matching. When you
have a good ground, you need an additional inductor.

When you provide some more info, you might get better feedback.

Best regards,

Wim
PA3DJS
www.tetech.nl