PSN-L Email List Message

Subject: RE: SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER
From: "Gary Lindgren" gel@.................
Date: Sat, 16 Aug 2008 10:50:01 -0700


James,

Are there any pictures of your Prengnether 201.

Gary

 

 

 

 

From: psn-l-request@.............. [mailto:psn-l-request@............... On
Behalf Of JAMES ALLEN
Sent: Saturday, August 16, 2008 9:36 AM
To: psn-l@..............
Subject: Re: SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER

 

Thanks for the additional information

James Allen

----- Original Message ----- 

From: meredith lamb   

To: psn-l@.............. 

Sent: Friday, August 15, 2008 11:12 PM

Subject: Re: SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER

 

James,

 

Wonderful attitude!  One more thing...sometimes the adjustment nuts, collars
etc., have a hex setscrew/s position lock/s somewhere thereon; look for
them, and

release, or tighten down as necessary also.  

 

Take care, Meredith

On Fri, Aug 15, 2008 at 6:35 PM, JAMES ALLEN  wrote:

Thanks Meredith.  I appreciate all the recommendations and tips for
adjusting what I think is a "beautiful piece of seismic equipment".  Your
email has re-inspired me to really tackle this challenge.  I will let you
know how it turns out.  

Many thanks again for you wisdom and help.

James Allen

----- Original Message ----- 

From: meredith lamb   

To: psn-l@.............. 

Sent: Friday, August 15, 2008 8:35 AM

Subject: Re: SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER

 

 

On Thu, Aug 14, 2008 at 9:34 PM, JAMES ALLEN  wrote:

Meredith Lamb or any member using a Sprengnether 201 Long Period unit:
There is an scale on the front of mine with the indicator pointer that is at
the fourth line from the top, which is essentially at the top stop, and will
normally oscillate to the 6th line from the top.  Is this where it is
supposed to be or should it be centered on the 20 unit scale which after a
year of off and on fiddling seems impossible?

James Allen  

 

Hmmm....either its my computer malfunctioned or ?, but here I see my
response to Randall showing up below your message above???

James,

 

It "sounds" like you need to give some more slack to the top wire (top rear
rotating knurled nut) ...just to allow the frame/mass to come

further down, which then allows the vertical seismometer boom/mass to get
within the true center range of your

boom range/pointer mechanism.  It normally should be able to range over the
entire pointer scale of course.  My wild guess is that the previous

owner/s had the same (which IS entirely solvable) problem also; but didn't
do the necessary adjustment/s.

 

Remove the coil and dampening coil wires before exploring the adjustment
mechanisms.  I don't know what you've done before; so, all

I can do is text the below.

 

At the rear top is a knurled round threaded wire adjustment which will
raise/lower the wire (and which changes the period).  Try rotating that

slowly over whatever reaction range first....in conjunction with varying the
front set screw, which you'll need to do probably constantly.  Its

entirely possible that even a slight partial rotation or more; will get you
into a full range of its indicator pointer.  

 

Another potential "indicator/answer" could lie in your front single set
screw adjustment setting.  Try rotating that over a reasonable range

and observe whether the boom/mass hits the stop at the top the majority of
the time.  If (the boom/pointer) hits the top stop limit and stays there the

majority of the set screw range change; then that reaction would might
re-affirm you need for more wire slack as above.

 

Adjusting both the front set screw and the top back screw is critical for
this "boom/mass balance/pointer range" or in short; just being able to

see its oscillation movement range.  The whole thing is kind of a crude
weight balance with the spring acting as kind of a varying pivot force.

 

IF.....you've done all this before (?), and it still tends to go to the
upper range limit/stop....then you might actually have to unclamp the

compression wire fitting and feed abit more wire down.  Thats a really nasty
job, as you'll be physically fighting the strong spring tension

while trying to place the wire lower and also be ready to tighten the
compression wire clamp.  Its possible that the previous owner/s might

have cut off the exposed wire coming out of the wire adjustment at the
top/back (?), there should normally be some wire coming out there?

If there isn't any wire....and you're at the limit of adjustments...you may
have to rewire it to give more room/slack of course.  We can get

into that if necessary.

 

I have a love-hate relationship with this coil/magnet vertical.  I like its
long mechanical period; but I hate its temperature sensitivity.  All in all,
its

worth fussing with....theres no real mechanical alternative of course;
outside of electronic extension of lesser period gizmo's.   Most 

amateurs have no vertical whatsoever....

 

Take care, Meredith

 

 

 

 

 

          

 












James,

Are there any pictures of your Prengnether = 201.

Gary

 

 

 

 

From:= psn-l-request@.............. [mailto:psn-l-request@............... On = Behalf Of JAMES ALLEN
Sent: Saturday, August 16, 2008 9:36 AM
To: psn-l@..............
Subject: Re: SPRENGNETHER 201 LONG PERIOD VERTICAL = SEISMOMETER

 

Thanks for the additional information

James Allen

----- Original Message -----

From: meredith lamb =

Sent:<= /b> Friday, = August 15, 2008 11:12 PM

Subject: Re: = SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER

 

James,

 

Wonderful attitude!  One more = thing...sometimes the adjustment nuts, collars etc., have a hex setscrew/s position lock/s somewhere thereon; look for them, and

release, or tighten down as = necessary also. 

 

Take care, = Meredith

On Fri, Aug 15, 2008 at 6:35 PM, JAMES ALLEN <jcallen1@...........> = wrote:

Thanks Meredith.  I appreciate all the recommendations and tips for = adjusting what I think is a "beautiful piece of seismic = equipment".  Your email has re-inspired me to really tackle this challenge.  I will = let you know how it turns out. 

Many thanks again for you wisdom and help.

James Allen

----- Original Message -----

From: meredith lamb =

Sent:<= /b> Friday, = August 15, 2008 8:35 AM

Subject: Re: = SPRENGNETHER 201 LONG PERIOD VERTICAL SEISMOMETER

 

 

On Thu, Aug 14, 2008 at 9:34 PM, JAMES ALLEN <jcallen1@...........> wrote:

Meredith Lamb or any member using a Sprengnether 201 Long Period = unit:  There is an scale on the front of mine with the indicator pointer that is at the fourth line from the top, which is essentially at the top stop, = and will normally oscillate to the 6th line from the top.  Is this = where it is supposed to be or should it be centered on the 20 unit scale = which after a year of off and on fiddling seems = impossible?

James Allen  

 

Hmmm....either its my computer malfunctioned or ?, = but here I see my response to Randall showing up below your message = above???

James,

 

It "sounds" like you need to give some = more slack to the top wire (top rear rotating knurled nut) ...just to allow = the frame/mass to come

further down, which then allows the vertical seismometer boom/mass to get within the true center range of = your

boom range/pointer mechanism.  It normally = should be able to range over the entire pointer scale of course.  My wild = guess is that the previous

owner/s had the same (which IS entirely = solvable) problem also; but didn't do the necessary adjustment/s.

 

Remove the coil and dampening coil wires before = exploring the adjustment mechanisms.  I don't know what you've done before; = so, all

I can do is text the below.

 

At the rear top is a knurled round threaded wire = adjustment which will raise/lower the wire (and which changes the = period).  Try rotating that

slowly over whatever reaction range = first....in conjunction with varying the front set screw, which you'll need to do = probably constantly.  Its

entirely possible that even a slight partial rotation or more; will get you into a full range of its indicator pointer. 

 

Another potential "indicator/answer" = could lie in your front single set screw adjustment setting.  Try rotating that over a reasonable range

and observe whether the boom/mass hits = the stop at the top the majority of the time.  If (the boom/pointer) hits = the top stop limit and stays there the

majority of the set screw range change; then that reaction would might re-affirm you need for more wire slack as = above.

 

Adjusting both the front set screw and the top = back screw is critical for this "boom/mass balance/pointer = range" or in short; just being able to

see its oscillation movement range.  The whole = thing is kind of a crude weight balance with the spring acting as kind of a = varying pivot force.

 

IF.....you've done all this before (?), and it = still tends to go to the upper range limit/stop....then you might actually have to = unclamp the

compression wire fitting and feed abit more wire = down.  Thats a really nasty job, as you'll be physically fighting the strong = spring tension

while trying to place the wire lower and also be = ready to tighten the compression wire clamp.  Its possible that the previous owner/s might

have cut off the exposed wire coming out of the = wire adjustment at the top/back (?), there should normally be some wire = coming out there?

If there isn't any wire....and you're at the limit = of adjustments...you may have to rewire it to give more room/slack of course.  We can get

into that if necessary.

 

I have a love-hate relationship with this = coil/magnet vertical.  I like its long mechanical period; but I hate its = temperature sensitivity.  All in all, its

worth fussing with....theres no real mechanical = alternative of course; outside of electronic extension of lesser period gizmo's. =   Most

amateurs have no vertical = whatsoever....

 

Take care, Meredith

 

 

 

 

 

          =

 


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