An AM RADIO is only so good.... Field Strength Meter

When hunting out alleged RF interference source the only advice I have
ever seen for the layman is to use an off tune AM/LW radio. My trusty old
Roberts (http://www.amazon.co.uk/gp/product/images/B0000ULWZM/
ref=dp_image_z_0?ie=UTF8&n=560798&s=electronics) seems to fit the bill.

This seems to have mixed results and knowing where to look and what to
listen to would be useful. I basically listen for any horrible noise that
would suggest a problem. I'm guessing anything oscillating badly in band
would be the starting point?

It crossed my mind that rather than paying hundreds of pounds for a
detector of some kind, it may be possible to produce a cheap and
effective Field Strength Meter with a variable RF amp to do this job out
of scrapbox parts. Does anyone have any experience or a view on this?

Barry On Surfin' wrote:
> When hunting out alleged RF interference source the only advice I have
> ever seen for the layman is to use an off tune AM/LW radio. My trusty old
> Roberts (http://www.amazon.co.uk/gp/product/images/B0000ULWZM/
> ref=dp_image_z_0?ie=UTF8&n=560798&s=electronics) seems to fit the bill.
>
> This seems to have mixed results and knowing where to look and what to
> listen to would be useful. I basically listen for any horrible noise that
> would suggest a problem. I'm guessing anything oscillating badly in band
> would be the starting point?
>
> It crossed my mind that rather than paying hundreds of pounds for a
> detector of some kind, it may be possible to produce a cheap and
> effective Field Strength Meter with a variable RF amp to do this job out
> of scrapbox parts. Does anyone have any experience or a view on this?

Its called a DSL modem :-)

The rather irritating thing is that what you want is what the DSL modem
and associated circuitry does, anyway.

If you try and build a broadband amp it will be saturated by Droitwich
and so on. A narrow band amp like the Roberts doesn't tell you ALL that
much.

What you need is a device that screens out the mots powerful interfering
signals and works out what in between is usable. A DSL modem in fact!

Ideal is of course a spectrum analyser, but they don't come cheap.