Using BOTH an attenuator and static discharge resistor
Dennis
shortwave using a random wire antenna:
http://www.kc7nod.20m.com/atten_.htm
But I also need static discharge capability to protect my receiver.
Here is one from the same site:
http://www.kc7nod.20m.com/static_dis.htm
These both seem like straightforward, solid circuits. However, if
they're used together, wouldn't a static charge take the path of least
resistance which would be the attenuator out the center tap and
straight to the radio?
If I'm correct, is there an attenuator/static discharge circuit that
will work together?
Thanks!
Mark S. Holden
You could hook the potentiometer to the output of the static discharge
circuit, so the signal goes through it before it gets to your attenuator
circuit.
r2000...@hotmail.com
lighting strike(or EMP event) safely to ground.
If you are worried, use the 0.01uF 500WV cap
in series with the CENTER/WIPER output.
In the "static" discharger I doubt if the NE2 will
ever flash, the 10K will effectivly bleed most static
to ground.
I wish there was an easy way to post drawing in a NG.
Print both diagrams, and wire the pot in the place of the
10K fixed resistor., place the capacitor between the wiper
and the output jack.
There one box that serves both functions.
Terry
RHF
.
Portable AM/FM Shortwave Radio-to-Antenna "GIZMOE" Connector Box
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/2070
.
READ - Portable Radio Antenna "GIZMOE" Connector Box
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/1489
.
A Second Look - Radio/Receiver Antenna "GIZMOE" Connector Box
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/957
NOTE - Improved Circuit and Description :
+ Continuous "Ground Rail" 'tie-in' for All Components
+ Jack-Connector to 'match' the Antenna Lead-in.
+ High Voltage Discharge protection using Gas Discharge Tube
+ Low Voltage Surge protection using Front-to-Back Dual Diodes
+ Static Discharge protection using 10K Ohm Potentiometer
+ + RF Signal Attenuation using the same 10K Ohm Potentiometer
+ Not-in-Use protection using an Circuit "Open" Switch
+ Plug-Connector to 'match' the Radio's External Antenna Input.
.
Portable Radio Antenna "GIZMOE" Connector Box
http://groups.yahoo.com/group/Shortwave-SWL-Antenna/message/7
.
iane ~ RHF
.
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Shortwave Listener (SWL) Antenna eGroup on YAHOO !
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.
CW
attenuator and the radio are all common to the coax shield and should bonded
to a ground rod.
CW
KC7NOD
"Dennis" <IntellP...@lawyer.com> wrote in message
news:1106949315....@z14g2000cwz.googlegroups.com...
Dennis
reading your posts. The static charge will take the easiest path to
GROUND, so there's now reason why it would bleed through the reciever.
I've done a fair amount of research on this lately. The Gizmoe box
looks interesting, and most of the circuits are fairly similar. I
agree that the neon light probably isn't very effective unless the
bleed resister fails. By the time it fires, though, it's probably too
late.
What I would like to do is build the circuit in an aluminum project
enclosure. The circuit will be similar to most of the ones you folks
talked about. One circuit I found interesting is in an excellent
article: ttp://www.qsl.net/wd8das/2010.html The problem is that I
cannot read the component values because the image is all blurry. Can
anyone tell me what they are? I would like to add the .05 uF cap
inline with the center wiper of the pot. The only thing I'm not sure
about is how all this will affect my mfg reciever antenna tuner. Will
the resistance and capacitance cause problems with the tuner?
Rather than use any type of switch, I'll simply unplug the antenna and
place it outside the window it runs through when I'm not using it. A
value of 10k for the bleed resistor sounds pretty low. I've heard
people talk of values as high as 100k or even 1meg!
Thanks again to everyone. I feel like my protector box is honing in
nicely and should have it put together in another day or two. If
someone can tell me what the component values are in the WD8DAS
schematic, I would really appreciate it.
Dennis
the author of the article and he was kind enough to write back and give
me a detailed explanation. I believe he's using a 2K pot. I'll
probably put a 10k pot in series with a 1k resistor and take it from
there. I appreciate your advice. Now I have a pretty clear picture on
how my "Gizmoe Box" will work.
GO PATRIOTS!
CW
the neon bulb one. Same diode recommendations. The attenuator in the wd8das
circuit is the same also. They are just shown, in this case, separately. The
pot he (wd8was) has on his schematic is specified as 1 to 10K. Anything in
this range will work. The higher value will give you finer control. The 10K
pot in series with a 1K resistor will not work well. It will just limit your
attenuation range one way or the other, depending on what side you put it
on. If you were to put them in parallel, you would simply be reducing a 10K
pot to a 909 ohm pot. The neon bulb circuit does have advantages. The
bleeder resistor constantly bleeds static keeping at a low level as opposed
to the diodes that have to reach a certain level before they conduct. The
neon bulb fires more often than you might imagine. Build it with the bulb
exposed and watch. You could, of course, do a variation. Build the wd8was
circuit and put a bleeder resistor before it. None of this stuff is new. You
can see that there are variations. You are not stuck with one design.
Whatever you do though, make sure it is of sound design.news:1107714377.3...@f14g2000cwb.googlegroups.com...