[Discuss-gnuradio] Re: Cheap receivers...

[ah7i]

See http://www.nitehawk.com/sm5bsz/linuxdsp/linrad.htm
for some cheap receiver ideas, good to GHz range.

What's this for?

I have some FM IF strips. 45MHz in, approx 30kHz bandwidth
that you could use with a real basic RF amp and mixer.
I sell these. Write for detail.

100+ mile reliable communication is difficult
in one hop. Tropospheric ducting can work
most of the day for most of the year in tropics
but...

Is thie related to the peace corps internet project in africa?

-Bob


> Date: Tue, 29 Apr 2003 12:11:26 +0100
> From: Raphael Clifford <address@hidden>
> To: address@hidden
> Subject: [Discuss-gnuradio] cheap receivers

> I am starting a project to broadcast data to display terminals in
> Africa.  I need long distances (>100 miles) and *really* cheap
> receivers.  As I am new to this please forgive my ignorance but I don't
> understand a few things.
>
> It seems to me that the cheapest way to build a receiver is to wire a
> standard AM radio to your computer. The two options are through the
> standard audio out and modifying a radio to bring out a connection to
> the Narrowband discriminator.  So my questions are
>
> 1) I am not at all clear what the advantage of the latter technique is
> in terms of bandwidth.  Can anyone tell me? As far as I can tell you get
> frequencies in the range 300-3000Hz from the audio output and 0-3000Hz
> from the discriminator so there is only a marginal gain.  However, I am
> very much a newbie.  Is there are significant increase in the quality of
> the signal from the discriminator at all frequencies?
> 2) Can the output of both techniques be decoded in software without any
> further hardware?  I can't afford to spend money on dedicated hardware
> for the receivers.
> 3) Is this approach of using an AM radio a stupid one in the first
> place? Is there a much better way?
> 4) What should I read to bring myself up to date on the issues involved?
>   For example, how would I calculate the expected bandwidth from
> different frequencies/coding techniques etc.?
>
> Cheers,
> Raphael