On Feb 8, 8:07 pm, "art" wrote:
On 6 Feb, 20:55, "T" wrote:

i'm working on a science fair project. i'm building an am-radio
transmitter. i can only be a few inches from the receiver. how do i
solve this problem without making my antenna enormous.

Placing the amplifier at the antenna prevents noise
from
overpowering the incomming signal The amplifier need only to be a
simpleIf you build an amplifier at the initial recerving antenna which is
preferably
outside the house the signal within the coax leading to and within
the house
will be strong enought to overcome the losses entailed by using a
long
connecting coax.


I think he means the AM broadcast band.. Or I assume anyway.
The loss with most any length of coax at that MW freq should be
dinky indeed.
I built one of those when I was about in 7th grade. Mine had like
a small tight wound loop for an antenna if I remember right. But I
might
have even tried hooking it to to my then SWL antenna which was a 50
ft random wire. I don't know how critical the transister? is as far as
match. If it's not picky, you could probably just string out a short
wire. There are probably FCC antenna standards as far as such a
device,
but I'm too lazy to look them up.. I don't think the FCC wants them
radiating too far. As far as receiving at MW, Any commercial radio
should be good enough with whatever antenna came with it.
Well, unless it's a really lousy radio.. If you can hear noise
in between stations in the daytime, it's good enough and can't really
be
improved too much as far as s/n ratio.
MK