Re: sound card AM Transmitter

Dirk Bruere at NeoPax wrote:
Jerry Avins wrote:
cs_posting@xxxxxxxxxxx wrote:
On Jul 30, 11:20 am, Jerry Avins <j...@xxxxxxxx> wrote:

How far do you expect it to propagate with an antenna of reasonable (say
50 meter) size? What will serve as a receiver?

I don't expect it to propagate very far, but who knows what the OP is
up to. We don't even know for a fact that antenna are involved -
there could be a transmission line between transmitter and receiver.
Or we could be misinterpreting the question - 20 KHz might be the
modulation bandwidth, not the carrier frequency.

For antenna lenght, the legal limit in the US for the 160 - 190 Khz
band appears to be 15 meters for the total length of of antenna, feed
line, and ground lead. I'm not sure what, if anything, is allowed
below 20 KHz.

If the transmitter is a sound card, the receiver might be as well. Or
something involving an op-amp for gain, a diode detector, and an op-
amp lowpass filter.

Be advised that the whole project is a fantasy. If a transmission line is involved, why modulate? Our friend Masood needs to learn a lot even to understand his own question. If he asks more questions, I and others will try our best to enlighten him.

Jerry

Maybe it's not an antenna in the RF sense but an inductive loop device.

So why modulate? We've seen Masoud's questions before. Some of them make sense, but none admit the kinds of sophistication that others are willing to suppose.

Jerry
--
Engineering is the art of making what you want from things you can get.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
.

Relevant Pages

  • Re: Best Way to build a calibrated S meter
    ... source and the receiver. ... AGC that using for aiming antennas was annoying. ... I found the N6NB method using a VU meter with the AGC off very useful. ... There is a fax station in Germany running 20 kw or so, into a vertical antenna on 13,882 or somewhere around their. ...
    (rec.radio.amateur.homebrew)
  • Re: sound card AM Transmitter
    ... 50 meter) size? ... there could be a transmission line between transmitter and receiver. ... For antenna lenght, the legal limit in the US for the 160 - 190 Khz ...
    (comp.dsp)
  • Re: sound card AM Transmitter
    ... 50 meter) size? ... there could be a transmission line between transmitter and receiver. ... For antenna lenght, the legal limit in the US for the 160 - 190 Khz ...
    (comp.dsp)
  • Re: Vertical vs Horizontal shootout part one
    ... what kind of antenna is feeding it, is the signal strength at the ... Any changes in the antenna ... you could make a receiver with very nearly true logarithmic ... meter is really indicating, so they wouldn't pay the added cost for it. ...
    (rec.radio.amateur.antenna)
  • Re: Verticals versus Horizontal Dipoles
    ... If you don't have a signal generator with variable output, connect the two feedlines through a DPDT switch so it swaps the antenna to each receiver when you switch it back and forth. ... Write down the meter reading on each receiver for the same signal from the same antenna. ...
    (rec.radio.amateur.antenna)