A wide coverage receiver will tell you quite a lot.
Access to its IF or audio output will give you some idea of
quantitative signal strengths.
.
Small portable TV's with multiband manual tuning allow you to tune
across hundreds of MHz (from about 40 MHz up) and SEE the signal. it
really works - I've done it. The manual intensiveness of the task is
a disincentive.
A "scanner" type receiver may also be useful but I haven't tried
this.
.
"Good Spectrum Analysers" have been mentioned.
The "gooder" the better of course but you can build a hobbyist
spectrum analyser from magazine projects for about $US100 which use a
tv tuner and are surprisingly capable (I have one which  i built
based on an Electronics Australia kitset design). Ain't HP or Tek but
it does work.
Add a few lowish cost accessories such as a comb generator (for spot
frequency calibration) and a bit of ingenuity and you can get a fair
idea of how well your device performs.

Below 30 MHz you are looking at largely conducted signals - look at
the standards (in our libraries, maybe on the net) and see what they
are aiming at - a cheap absorbing clamp using surplus ferrites should
be possible. (I haven't tried this, yet).


-----Original Message-----
From: Nigel Orr- Underwater Acoustics Group <Nigel.Orr@NCL.AC.UK>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Tuesday, September 15, 1998 8:00 PM
    Subject: Re: [OT] UK/EU compliance testing for prototypes


>At 09:06 14/09/98 -0700, you wrote:
>>You would use the compliance route called "Self Declaration". This
means you
>>consult with testing agencies on finding the best catagory for your
>>product(s) or you just select the "generic" EN50081 catagory. Then
you apply
>>or have the test agency apply the necessary tests to fulfill the
>>specification.
>
>This is still quite pricey- I've looked into it, but none of the
normally
>touted options are really suited to the hobbyist who is relatively
>confident that the device is designed well and will not malfunction
due to
>external EMF, or cause others to do so.
>
>What I would like is a simple item I could build, or buy cheaply,
with
>which I could test items which I feel are likely to "pass by a
mile"- so if
>I test them myself, in non-laboratory conditions, with simple tests,
and
>they pass those effortlessly, then I can confidently assume they
will pass
>the "easier to pass but more costly to implement" tests required for
actual
>compliance.
>
>I realise that some manfuacturers are pumping equipment which just
"nips
>through" the tests, but many products, such as low frequency, small,
well
>designed PIC circuits will, as someone has mentioned, probably not
even
>register on the tests- surely there's some simple tests which could
be done
>"at home" to verify this- and if emissions are within an order of
magnitude
>of the limits, one could go for the real tests to be sure?
>
>>There are other routes to pursue, but I would consider self
declaration the
>>most efficient and least costly for small operations.
>
>Where small is a business producing one or two hundred, maybe- where
small
>is a hobbyist producing less than ten- definitely not!  List the
prices,
>divide them by 10, and see what effect that has on a product with a
parts
>cost of about 10 to 20 dollars?  A large one!
>
>Nigel
>--
>Nigel Orr                  Research Associate   O   ______
>        Underwater Acoustics Group,              o / o    \_/(
>Dept of Electrical and Electronic Engineering     (_   <   _ (
>     University of Newcastle Upon Tyne             \______/ \(
>