Hi Chris

Q: How many spikes do you see per hour and are they a ~single pulse or
several? 
A: There are several spikes pr hours, this is sigle pulse. They can be
seen on my online tremor plots. 
Q: What sizes are they?
A: There size is variable, the largest one are few mm in size. There is
a diffrent between grund spikes (pepole, traffic etc..) then these
single spikes.
Q: Are there any particular times over 24 hrs when the interference is
more severe? 
A: This spikes happens mostly over the day, however I have seen them
late night and during the night. Even when the traffic noise is minimal.

I don't know if my fridge has electronic motor. It has tank like item in
it. But it problay is a motor.


> You can also get large spikes on the electricity supply if there are
> any 'industrial' users nearby. Large electric motors and electric
> welding are common sources within several km. 

There is a factory few meters (around 200 - 500 meters) away from me.
They do use heavy electronic hardware, but i don't think that is the
problem. Since the electronic system is good and farly new (~20 year
old).

> They may also be due to switching between electricity generating plant
> and this can effect wide areas. It is often observed as a momentary
> dimming of electric light bulbs and the momentary failure of 1 to 2 m
> long strip light tubes. 

Only time I see dimming of electonic light bulbs is during winter storms
that hit the electronic grid in Iceland hard. Over the summer this
almost never happen, unless there is a failure in the electronic grid.


> The normal method is to provide protection against transient spikes
> with a filter on the supply system and to provide large electrolytic
> storage capacitors on your power supplies. This enables the amplifier
> rail voltages to remain constant during a momentary power failure.

I plan to buy UPS with the computer and the WinSDR board, so it can work
if i loose power during winter storms or if something else goes wrong. I
just don't know when I can buy it.

Q: Do you have house power wiring with three of just two connecting
pins, and what voltage is it?

There are three wires, two for electronic and one for ground. This is
two phase electronic power system that I use, Iceland uses 220v/50Hz. I
also have a 10 amp electronic fuse. With that the apartment is also
breaked down to 5 parts, each haveing it's own power fuse, larger
electronic have larger fuse, 16 amps and 25 amps the larger ones.


> You can also buy 'uninterruptable power supplies' for computers and
> similar low power equipment. These have an auxiliary 12/24 V backup
> lead acid battery which keeps the systems running during short power
> failures. Switch over time is about 1/2 a supply power cycle, 1/100 or
> 1/120 second. They may have a data link to the computer to enable it
> to save data / close down automatically. 

I plan to, I just don't know when I can afford it.

Q: What sort of power supplies are you using for your amplifiers and are
the common 0 V rails on amplifier boards effectively earthed at the
signal input pins?    
A: I am using the power converter that Larry did sell me. It has been
working without a problem. Other then that, I don't know.
Q: Do you get much lightning? 
A: No, it sometimes happen during the summer and last week has been
clear of any lightings in Iceland.

Here is what I did when the problem did start happening. Becose of my
small place in my apartment, I had the wire from the geophone on the
floor to start with. But two weeks ago, I did remove the wire off the
floor with a list and put it near the sealing (or however it is
spelled). Then the problem started to happening. It might be that the
wire did act like a antenna, but I am not sure. For testing i did put
the wire back down to the floor to see what happens in the next week, in
order to get some comparision.

Regards.
-- 
Jón Frímann
http://www.jonfr.com
http://www.simnet.is/jonfr500/earthquake/

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