In a message dated 26/05/06, jonfr500@......... writes:

> Is there any way for me to reduce the spike problem that I am having?
> I can draw up the current setup to explain the problem if needed.

Hi Jon, 

       How many spikes do you see per hour and are they a ~single pulse or 
several?  What sizes are they? Is the size very variable? Are there any 
particular times over 24 hrs when the interference is more severe?

       Spikes on a quake trace are often due to pulses on the electricity 
supply in the house. Refrigerators which have an electric motor can put large 
spikes on the system as they turn on and off. If you have a fridge of this type, 
note when it turns on and off - maybe also try switching it with a wall socket 
switch - and look for spikes on the trace. Do you have electric heating in 
the house controlled by time clocks / thermostats? Since you live in a block of 
houses, you may also pick up local interference from other users. 

       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.  

       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.

       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.

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

       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. 

       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?   

       Do you get much lightning?

       Regards,

       Chris Chapman
In a message=20=
dated 26/05/06, jonfr500@......... writes:



Is there any way for me to=20=
reduce the spike problem that I am having?

I can draw up the current setup to explain the problem if needed.=




Hi Jon,=20



       How many spikes do you see per hour=
 and are they a ~single pulse or several?  What sizes are they? Is the=20=
size very variable? Are there any particular times over 24 hrs when the inte=
rference is more severe?



       Spikes on a quake trace are often d=
ue to pulses on the electricity supply in the house. Refrigerators which hav=
e an electric motor can put large spikes on the system as they turn on and o=
ff. If you have a fridge of this type, note when it turns on and off - maybe=
 also try switching it with a wall socket switch - and look for spikes on th=
e trace. Do you have electric heating in the house controlled by time clocks=
 / thermostats? Since you live in a block of houses, you may also pick up lo=
cal interference from other users.=20



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



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



       The normal method is to provide pro=
tection against transient spikes with a filter on the supply system and to p=
rovide large electrolytic storage capacitors on your power supplies. This en=
ables the amplifier rail voltages to remain constant during a momentary powe=
r failure.



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



       You can also buy 'uninterruptable p=
ower supplies' for computers and similar low power equipment. These have an=20=
auxiliary 12/24 V backup lead acid battery which keeps the systems running d=
uring short power failures. Switch over time is about 1/2 a supply power cyc=
le, 1/100 or 1/120 second. They may have a data link to the computer to enab=
le it to save data / close down automatically.=20



       What sort of power supplies are you=
 using for your amplifiers and are the common 0 V rails on amplifier boards=20=
effectively earthed at the signal input pins?   



       Do you get much lightning?



       Regards,



       Chris Chapman