On Tue, 15 Sep 1998, Quentin wrote:

> > be calibrated, but can you give me an idea of how voltage level from this
> > arrangement will relate to emissions specs?
> >
> That I can not tell you. It's been a while since I've used something like
> this myself, but I am sure somebody will work out the relation.
> As I said, this is homebrew just to give you indication of emissions, and
> where to locate them.

I've had similar concerns and I've come up with the following: using a
signal generator and a similar loop terminated by a 50 ohm R. I set the
generator to 1 mW output and take a reading with the probe 2.5 cm from it,
getting the maximum reading. I repeat the process at about 3 frequencies
(e.g. 500 kHz, 2 MHz, 10 MHz). This is not an authoritative method, but it
will tell you what is leaking.

The loop method tests only for current (especially if terminated as I
advocate). For voltage (E field) a prod probe is more useful. This can be
a unmodified scope probe set to x 10 with the clip-on gripper prolonged by
a 25 mm piece of rigid wire, as antenna. The x10 setting is essential
imho. The probe is "calibrated" in the same way as above.

I've used the exact same probes with HP spectrum analyzer with good
(non-auhoritative) results.

Peter