[TenTec] Ladder Line Static Discharge

Stephen M. Shearer wb3lgc at verizon.net
Fri Jan 20 16:05:46 EST 2006


Having had to re-look at my lightning protection, did find the I.C.E. surge
suppressors are DC blocking and have an inductor from each side of the
ladder line to ground.  I guess I could measure the inductor.

(also note; that a 4:1 voltage balun provides an inductive path to ground
for both sides of the ladder line.  Just add a capacitor for dc blocking and
a pair of gas tubes for surge suppression and you have an I.C.E. balanced
line surge suppressor.)

See: http://www.iceradioproducts.com/impulse1.html#2

When I asked about the coax suppressor:
I have one of your Model 301 HF Arrestors.  Before I use it to protect my
$4000 radio, I would like to find some specifications for the unit.  Your
documentation seems lacking. Do you have documentation for:

Throughput Energy for 3kA @ 8/20μs Waveform?
Turn on time?
(aka how does it compare to the PolyPhaser coax models)

I got this reply:
Hi, Steve.  No lightning hit arrives at the arrestor at the 8/20 standard. 
Figure in the RL time loss constant of the coax line to figure the exact
waveform at entry.  Because the unit uses an RF choke to extend the
transmission line into the chassis (earth ground) it's difficult to state
the exact attack time.  Using the attack time of the gas tube it would be
2-5 ns.  Another problem with the 8/20 standard is that it represents 1/2
cycle of roughly a 100Khz. waveform.  But the componentry of the 301 is
essentially a highpass filter circuit.  At 100Khz. the attenuation of the
arrestor is roughly 80db.  We would estimate the throughput energy to be
less than 1 joule, since a resisitive means is employed on the arrestor's
equipment side to shunt that also to the chassis.  The really important
factor is to employ a ground service connection that is low or no inductance
and can handle an equivalent amount of current that can be delivered by the
transmission line.  No 301 arrestor has ever failed in service.  Thanks,
regards...M. Koss, Sales




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