[TowerTalk] Ferrite beads for common mode current

[jeremy-ca]

> Jim Brown's paper has very high quality measurements done with
> traceably calibrated lab gear (a VNA) on a wide variety of
> configurations.  Not that measurements done 20-30 years ago are not
> valid, but measurement technology has improved a lot, particularly
> for high insertion losses.   The ability to make the measurements
> more rapidly means you can make 30 measurements intead of one, and
> that lets you spend more time on doing good fixturing for the
> tests.  The other thing is that modern test equipment does fixture
> calibration for you.
>
> (I want a Agilent 4 port PNA-X with the two sources and an E-cal for
> my garage, although I wish it went down to 300kHz like the N5230A!  I
> wouldn't turn down a more elderly 8753..)
>
> Jim, W6RMK

My shop currently has a 8757A, 8753B and an assortment of SA's, sig gens, 
sweeper, NF meter, cal sets, etc. Older technology but more than adequate 
for my needs. Plus they show up at rather distressed prices in this area. A 
friend who was the cal lab manager at a previous job now has his own shop 
out of his home and thinks he can land me a 8510B with a load of accesories 
at a bargain price.

The advent of the E series and later has taken its toll on the resale 
market. Cal shops are closing as qualified techs are retiring or changing 
professions. Pretty soon the venenerable 141T package and others of the era 
are going to be a collectors item on Ebay bringing huge prices!

Carl
KM1H