[Elecraft] scope suggestions?

Wed Jan 21 12:00:01 2004

One thing to keep in mind about scope "bandwidth" is that you normally =
want
a bandwidth rating considerably more than the fundamental frequency of a
signal you're likely to want to investigate if you want to see the =
detail in
waveforms accurately. Something on the order of 5 to 10 times the =
highest
signal frequency is a sort of "rule of thumb" I've always heard. So, for
"typical" HF work, a bandwidth of 100 MHz or more is a good idea. =
Otherwise
a lot of the small 'detail' - the squiggles and other artifacts that are =
the
reason for investigating many waveforms - are lost because the frequency =
of
the artifact is much, much higher than the basic frequency of the =
waveform.
The result is that waveforms look much cleaner on a lower-bandwidth =
scope
than they really are.

A low bandwidth scope is fine for simply checking that logic is =
switching.
Multiple traces are very handy for looking at the relative timing of two
signals at once. Simple "logic probes" with LED's often can provide that
information at much lower cost and smaller size. =20

Good USED scopes are fairly cheap, but a good SMALL scope is a different
matter.=20

One pays for portability. If the budget allows it, Fluke has for years =
sold
a very attractive little solid-state oscilloscope/DMM combo called the
"scopemeter" (see http://www.tequipment.net/Fluke192Bscope.html for an
example. They have a lot of models. My only connection with this vendor =
is
that I've been a customer and they seem to have competitive prices).=20

I drooled over one of these years past when I had to haul all of my =
tools,
spare parts and test equipment up seven or more flights of stairs for =
every
service call. I would have bought one except that my employer had a =
small
3-inch CRT-type Tektronics 'scope available that did the job I needed -
although it did weight more.=20

I haven't seen the little 3-inch Tek scopes on the used market for some
reason. It's been a decade since I hauled that 3-incher around. I don't
recall its bandwidth.=20

Ron AC7AC

-----Original Message-----
From: [email protected] =
[mailto:[email protected]]
On Behalf Of Bob Nielsen
Sent: Wednesday, January 21, 2004 8:11 AM
To: [email protected]
Subject: Re: [Elecraft] scope suggestions?

> Has anyone been scope shopping lately?
>=20

I bought a B&K 2120 at Fry's last week ($389.95).  It's only 30 MHz, but =
I
don't need to look at anything that high anyway.  They had one with =
delayed
sweep for a bit more.  It has dual-trace and X1/X10 probes were =
included.

Bob, N7XY