? on neon light as static discharge device
 

Dave wrote:
I saw somewhere that you could use an NE-2 bulb between the antenna "hot"
lead and ground as a static discharge device for a receiver, but can't find
an NE-2 and don't know anything about neon bulbs. Anybody know if a
standard neon bulb rated at 125 VAC could be used in this manner? Or how I
could test it? I'm thinking about charging up a 50V electrolytic capacitor
and hitting the bulb with that, to see if it discharges the cap. I have a
.22uF 630V mylar cap between the antenna and the input to the tuner because
the 35V disc I had there got blown, so I know that static can be a problem
with my setup even though it is grounded at two points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave


Most CB radios use a pair of back to back diodes across the receiver
input. I also recall the input of the ECG amplifiers also have the same
network to protect the Input circuitry from being blasted by the Pulse
from Defibrillator Paddles (1~5 KV.). These Back to back Diodes Clamp
the Voltage to the Forward Voltage Drop of the Diodes in question at
around 0.6 Volts. This circuit works much better and for cheaper than
the NE2 at ~60 Volts. If Static Electricity (lightning) is a problem at
a specific Frequency, a Grounded 1/4 wavelength shorted Stub could be
wired into the Feedline to present a DC ground to the entire antenna system.

Yukio YANO
VE5YS

? on neon light as static discharge device
 

"Yukio YANO" wrote in message
news:j3BKh.25152$DN.7632@pd7urf2no...
Dave wrote:
I saw somewhere that you could use an NE-2 bulb between the antenna "hot"
lead and ground as a static discharge device for a receiver, but can't
find an NE-2 and don't know anything about neon bulbs. Anybody know if a
standard neon bulb rated at 125 VAC could be used in this manner? Or how
I could test it? I'm thinking about charging up a 50V electrolytic
capacitor and hitting the bulb with that, to see if it discharges the
cap. I have a .22uF 630V mylar cap between the antenna and the input to
the tuner because the 35V disc I had there got blown, so I know that
static can be a problem with my setup even though it is grounded at two
points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave


Most CB radios use a pair of back to back diodes across the receiver
input. I also recall the input of the ECG amplifiers also have the same
network to protect the Input circuitry from being blasted by the Pulse
from Defibrillator Paddles (1~5 KV.). These Back to back Diodes Clamp
the Voltage to the Forward Voltage Drop of the Diodes in question at
around 0.6 Volts. This circuit works much better and for cheaper than the
NE2 at ~60 Volts. If Static Electricity (lightning) is a problem at a
specific Frequency, a Grounded 1/4 wavelength shorted Stub could be wired
into the Feedline to present a DC ground to the entire antenna system.

Yukio YANO
VE5YS

Of course! Back to back diodes! Why didn't I think of that? Thank you,
thank you, thank you. How obvious! :)

But is there any way that I could still use my neon bulb to let me know if a
pulse of high-voltage static hits the input to the receiver? I would love
it if there were some way to make that still work...

73's


Dave

? on neon light as static discharge device
 

"Dave" wrote in message
...

"Yukio YANO" wrote in message
news:j3BKh.25152$DN.7632@pd7urf2no...
Dave wrote:
I saw somewhere that you could use an NE-2 bulb between the antenna
"hot" lead and ground as a static discharge device for a receiver, but
can't find an NE-2 and don't know anything about neon bulbs. Anybody
know if a standard neon bulb rated at 125 VAC could be used in this
manner? Or how I could test it? I'm thinking about charging up a 50V
electrolytic capacitor and hitting the bulb with that, to see if it
discharges the cap. I have a .22uF 630V mylar cap between the antenna
and the input to the tuner because the 35V disc I had there got blown,
so I know that static can be a problem with my setup even though it is
grounded at two points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave


Most CB radios use a pair of back to back diodes across the receiver
input. I also recall the input of the ECG amplifiers also have the same
network to protect the Input circuitry from being blasted by the Pulse
from Defibrillator Paddles (1~5 KV.). These Back to back Diodes Clamp
the Voltage to the Forward Voltage Drop of the Diodes in question at
around 0.6 Volts. This circuit works much better and for cheaper than the
NE2 at ~60 Volts. If Static Electricity (lightning) is a problem at a
specific Frequency, a Grounded 1/4 wavelength shorted Stub could be wired
into the Feedline to present a DC ground to the entire antenna system.

Yukio YANO
VE5YS

Of course! Back to back diodes! Why didn't I think of that? Thank you,
thank you, thank you. How obvious! :)

But is there any way that I could still use my neon bulb to let me know if
a pulse of high-voltage static hits the input to the receiver? I would
love it if there were some way to make that still work...

73's


Dave


Question on this last note: What if I put the back to back diodes in series
with a 100K resistor, and they together in parrallel with the neon bulb.
Would that slow the discharge of a fairly large static pulse enough to light
the neon bulb, even briefly? I have the input to the receiver protected by
a fairly high-voltage (non-electrolytic) capacitor, so I'm not too worried
about the slowed-down pulse getting through to the rest of the circuit. And
if it did get through it would find an air-gap transmitting variable
capacitor next in line as the tuning cap. Is this a dumb idea, or might it
behave as I desire? Any ideas?

Thanks,

Dave

? on neon light as static discharge device
 

"Dave" wrote in message
...
Frank GM0CSZ / KN6WH

Thanks for the input, Frank. I believe this, or something like it, is
what I am going to have to do. I've already got the bulb installed in the
receiver case, and I guess I'll leave it there to warn me of impending
doom, but the resistor idea is what will probably save my bacon.

Is a metal-oxide resistor the same thing as a metal-film resistor? Or
would that be inductive and mess with my incoming signal?

Thanks much,

Dave


Why would the inductance be of any concern? It would
be effectively in series with the resistance, thus raising the
device's impedance... I'd think that would lessen the
loading on receive or transmit signals.

Pete

? on neon light as static discharge device
 

Dave wrote:

I saw somewhere that you could use an NE-2 bulb between the antenna "hot"
lead and ground as a static discharge device for a receiver, but can't
find
an NE-2 and don't know anything about neon bulbs. Anybody know if a
standard neon bulb rated at 125 VAC could be used in this manner? Or how
I
could test it? I'm thinking about charging up a 50V electrolytic
capacitor
and hitting the bulb with that, to see if it discharges the cap. I have
a .22uF 630V mylar cap between the antenna and the input to the tuner
because the 35V disc I had there got blown, so I know that static can be a
problem with my setup even though it is grounded at two points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave

Your "standard neon bulb rated at 125 VAC" probably contains a series
resistor of maybe 100kOhms, and so will be not much use for protecting
anything, because any current would develop too much voltage across the
series resistor. If you open it up and remove the resistor then it will be
able to shunt larger currents, though it still may not be ideal for
protecting receivers. (The main advantage of the neon as a protection
device is very low capacitance which could be important on the higher
frequency bands, but another advantage would be that it would introduce
practically no intermodulation even in very strong signal conditions, but
the breakdown voltage is probably so high that it may not protect solid -
state receivers very well, as someone else already mentioned. You can buy
a ceramic cased gas discharge surge arrestor, they are popular for
telephone circuits. e.g.:
http://www.epcos.com/inf/100/ds/ec350xx0810.pdf
)

You can probably make the bare neon bulb flicker by charging up something
with static electricity (e.g. rub a balloon on your head or on a jumper)
and then hold this near the bulb so you can hear crackling.

Chris

? on neon light as static discharge device
 

"Chris Jones" wrote in message
...
Dave wrote:

I saw somewhere that you could use an NE-2 bulb between the antenna "hot"
lead and ground as a static discharge device for a receiver, but can't
find
an NE-2 and don't know anything about neon bulbs. Anybody know if a
standard neon bulb rated at 125 VAC could be used in this manner? Or how
I
could test it? I'm thinking about charging up a 50V electrolytic
capacitor
and hitting the bulb with that, to see if it discharges the cap. I have
a .22uF 630V mylar cap between the antenna and the input to the tuner
because the 35V disc I had there got blown, so I know that static can be
a
problem with my setup even though it is grounded at two points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave

Your "standard neon bulb rated at 125 VAC" probably contains a series
resistor of maybe 100kOhms, and so will be not much use for protecting
anything, because any current would develop too much voltage across the
series resistor. If you open it up and remove the resistor then it will
be
able to shunt larger currents, though it still may not be ideal for
protecting receivers. (The main advantage of the neon as a protection
device is very low capacitance which could be important on the higher
frequency bands, but another advantage would be that it would introduce
practically no intermodulation even in very strong signal conditions, but
the breakdown voltage is probably so high that it may not protect solid -
state receivers very well, as someone else already mentioned. You can buy
a ceramic cased gas discharge surge arrestor, they are popular for
telephone circuits. e.g.:
http://www.epcos.com/inf/100/ds/ec350xx0810.pdf
)

You can probably make the bare neon bulb flicker by charging up something
with static electricity (e.g. rub a balloon on your head or on a jumper)
and then hold this near the bulb so you can hear crackling.

Chris

Hey Chris,

Thanks for the input. I am wondering why a neon bulb would include a 100K
resistor... To maybe lessen the current being driven through the bulb? I'm
going to have to check that out. Still, I am thinking that a couple of
back-to-back diodes each with a 100K resistor in series would probably do
what I want. Going to try my hand at building a test-bed and give it a
shot. Will check out the gas discdharge surge arrestor though. Sounds much
simpler, and likely more reliable.

Appreciate your feeback.

Dave

? on neon light as static discharge device
 

"Dave" wrote in message even in very strong
Hey Chris,

Thanks for the input. I am wondering why a neon bulb would include a 100K
resistor... To maybe lessen the current being driven through the bulb?
I'm going to have to check that out.
snip
..

Appreciate your feeback.

Dave

The neon lamp works the same as a gas voltage
regulator--about 80 volts or so IIRC...
The resistor serves to limit the current.

Pete

? on neon light as static discharge device
 

"Uncle Peter" wrote in message
...

"Dave" wrote in message
...
Frank GM0CSZ / KN6WH

Thanks for the input, Frank. I believe this, or something like it, is
what I am going to have to do. I've already got the bulb installed in
the receiver case, and I guess I'll leave it there to warn me of
impending doom, but the resistor idea is what will probably save my
bacon.

Is a metal-oxide resistor the same thing as a metal-film resistor? Or
would that be inductive and mess with my incoming signal?

Thanks much,

Dave


Why would the inductance be of any concern? It would
be effectively in series with the resistance, thus raising the
device's impedance... I'd think that would lessen the
loading on receive or transmit signals.

Pete



Hello Pete,

I was actually thinking something similar, that the diodes would prevent any
current from flowing through the circuit so long as the voltage remained on
the small-signal level. And if a large pulse did come through, the
inductance of the resistors would be the least of my worries. Any
interferrance it caused in my receiver would be brief and likely go
unnoticed. Does this sound plausible, or at least somewhat predictive of
likely real-life events in the case of a static charge coming down the line?

Dave

? on neon light as static discharge device
 

Dave wrote:


"Chris Jones" wrote in message
...
Dave wrote:

I saw somewhere that you could use an NE-2 bulb between the antenna
"hot" lead and ground as a static discharge device for a receiver, but
can't find
an NE-2 and don't know anything about neon bulbs. Anybody know if a
standard neon bulb rated at 125 VAC could be used in this manner? Or
how I
could test it? I'm thinking about charging up a 50V electrolytic
capacitor
and hitting the bulb with that, to see if it discharges the cap. I have
a .22uF 630V mylar cap between the antenna and the input to the tuner
because the 35V disc I had there got blown, so I know that static can be
a
problem with my setup even though it is grounded at two points.
Would welcome any ideas anyone has on how to make this work...

Thanks,

Dave

Your "standard neon bulb rated at 125 VAC" probably contains a series
resistor of maybe 100kOhms, and so will be not much use for protecting
anything, because any current would develop too much voltage across the
series resistor. If you open it up and remove the resistor then it will
be
able to shunt larger currents, though it still may not be ideal for
protecting receivers. (The main advantage of the neon as a protection
device is very low capacitance which could be important on the higher
frequency bands, but another advantage would be that it would introduce
practically no intermodulation even in very strong signal conditions, but
the breakdown voltage is probably so high that it may not protect solid -
state receivers very well, as someone else already mentioned. You can
buy a ceramic cased gas discharge surge arrestor, they are popular for
telephone circuits. e.g.:
http://www.epcos.com/inf/100/ds/ec350xx0810.pdf
)

You can probably make the bare neon bulb flicker by charging up something
with static electricity (e.g. rub a balloon on your head or on a jumper)
and then hold this near the bulb so you can hear crackling.

Chris

Hey Chris,

Thanks for the input. I am wondering why a neon bulb would include a 100K
resistor... To maybe lessen the current being driven through the bulb?
I'm
going to have to check that out. Still, I am thinking that a couple of
back-to-back diodes each with a 100K resistor in series would probably do
what I want. Going to try my hand at building a test-bed and give it a
shot. Will check out the gas discdharge surge arrestor though. Sounds
much simpler, and likely more reliable.

Appreciate your feeback.

Dave

I think that the diodes with resistors in series will probably not be ideal.

If you want to just discharge small steady currents of static electricity
being picked up by your antenna then all you need is a 100k (or 10k)
resistor from the antenna to ground.

If you want to protect against voltage spikes (e.g. caused by distant
lightning), (practically nothing will stop direct lightning) then your
diodes, connected in parallel, and one pointing in each direction, will
offer some protection, but in that case you must leave out the series
resistors because the series resistors will stop the diodes from performing
any useful function. If you are likely to experience strong radio signals
that could produce more than 0.2V on your antenna (and I would guess that
the answer is likely to be yes), then maybe the diodes will introduce
intermodulation (a form of interference) into your signal. In this case, a
number of diodes in series, in each direction, will allow larger RF signals
to pass without excessive distortion.

\|/
| Antenna
|
*-----\/\/\/\------. 100k resistor
| |
*--||--||--||---* 3x diodes, one direction
| |
*---||--||--||--* 3x diodes, other direction
| |
'--||--To Rx ___ Earth
Cap _

? on neon light as static discharge device
 

"Uncle Peter" wrote in message
...

"Dave" wrote in message even in very strong
Hey Chris,

Thanks for the input. I am wondering why a neon bulb would include a
100K resistor... To maybe lessen the current being driven through the
bulb? I'm going to have to check that out.
snip
.

Appreciate your feeback.

Dave

The neon lamp works the same as a gas voltage
regulator--about 80 volts or so IIRC...
The resistor serves to limit the current.

Pete


Gotcha. Thanks.

Dave