Transmitter

[Spookgud]

Hello my English is not so good so please dont pick me for that!
I whant help with my construction of a transmitter about 160 - 200 MHz.
I finnish with the PCB ver.12 i think every thing is right now.
I draw the chematics in Protel and have make the PCB there to.
I have simulate in Microwave Office and Orcad.
Now what I realy want help with is to tune it for the best performans but
still use same layout.
I have a power out around 70 - to 90 mW from a batteri 9V and 55mA and 50ohm
but I use stait vire and I dont realy now how much the impendans is.
I think I can get mor power out if I match the stage more good.
I also use transistor Philips BFG540.
If some on can give me some help i be very happy.
I can send you the chematics in PDF files or Protel if you prefere.

Best regards Peter

 

[Paul Burridge]

On Sun, 02 Jan 2005 15:54:03 -0800, Jamie
<jamie_5_not_valid_after_5_Please@charter.net> wrote:

i can suggest this, if you have an RF voltmeter or probe that you can
use to measure the signal from the wire, and then have an amp meter
in line with the power supply. using a tune able coil in series you
should be able to adjust for maximum RF voltage out with the minimum
current.
i only assume that your antenna is shorter than a quarter wave length ?
using an tune able inductor electrically increases the length to archive
resonance. this will give you max out put RF field that you can get with
that length of wire with a min current draw.
kind of a hack way of doing things but it works good in a pinch.

Try googling on "L-matching network" for a similar simple solution.
--

"What is now proved was once only imagin'd." - William Blake, 1793.