> Someone said the more mass the less movement from air currents etc.

That is one good reason, that had not occurred to me, but might also be 
offset by a large coil of sufficient size & weight.

> On the vertical sensor the mass is whatever is necessary to balance the 
> spring.

By "balancing the spring", I assume you mean a pendulum suspended 
horizontally by a diagonal spring?

> If you are about to build your first sensor, let me know, as I have two 
> simple vertical versions, very low tech. which work well.

Ted, I had two sensors built by John Cole from Texas.  One was a Lehman 
horz. and a custom vertical which was basically two custom-wound springs 
supporting a connecting metal beam that supported the coil which was 
suspended between the poles of the magnet.

I "fiddled" with those two sensors for almost a year, spend hundreds of 
dollars in texts and finally gave up.  I returned the devices to john, as he 
had requested.

I'm still interested in seismology as witnessed by my monitoring this group. 
BUT, much of what is discussed is frankly over my head.  Sensor "kits" are 
not available. Therefore, I remain somewhere between a "dumb ass" and a 
"wanta-be."

Yes, I would like to see these low tech designs that you have and you may 
send them directly to me at ab5r @ cox dot net, if you wish.

(BTW  I still have Larry Cochran's electronics configured for two sensors 
and his software)

Regards,
Jerry








> Someone said the more mass the =
less movement=20
from air currents etc. 
 
That =
is one good=20
reason, that had not occurred to me, but might also be offset by a large =
coil of=20
sufficient size & weight.  
 
> On the vertical sensor the mass is =
whatever is=20
necessary to balance the spring.  
 
By "balancing the spring", I assume you =
mean a=20
pendulum suspended horizontally by a diagonal spring?
 
> If you are about to build your =
first sensor,=20
let me know, as I have two simple vertical versions, very low tech. =
which work=20
well.
 
Ted, I had two sensors built by John =
Cole from=20
Texas.  One was a Lehman horz. and a custom vertical which was =
basically=20
two custom-wound springs supporting a connecting metal beam that =
supported the=20
coil which was suspended between the poles of the magnet.  =

 
I "fiddled" with those two sensors for =
almost a=20
year, spend hundreds of dollars in texts and finally gave up.  I =
returned=20
the devices to john, as he had requested.  
 
I'm still interested in seismology as =
witnessed by=20
my monitoring this group.  BUT, much of what is discussed is =
frankly over=20
my head.  Sensor "kits" are not available. Therefore, I remain =
somewhere=20
between a "dumb ass" and a "wanta-be."  
 
Yes, I would like to see these low tech =
designs=20
that you have and you may send them directly to me at ab5r @ cox dot =
net, if you=20
wish.
 
(BTW  I still have Larry Cochran's =
electronics=20
configured for two sensors and his software)
 
Regards,
Jerry