Will this work?

[Planeguysexploration]

An attempt at a homade attenuator. Will it work?

 

[wtp]

for reception only, there are no rules.
but with the 'ends' connected, you only get half the resistance.
could you tell us what radio this is for ?

 

[doctordialtone]

The beat way to determine whether it will work is to try it.

 

[Planeguysexploration]

It's for scanning, really any scanner I need it for. I tried it with mixed results. I asked the forums to see if this is the electrically correct method of wiring this.

 

[Planeguysexploration]

but with the 'ends' connected, you only get half the resistance.

What do you mean by "the ends"

 

[wtp]

it took a minute to figure out what you had attached the wires to.
a rheostat/volume control is a resistor connected at the 'ends' and arm that swipes from end to end, that is the middle connection.

 

[Planeguysexploration]

Of corse, however I was wondering if this would work as a variable resistor to block out weak signals.

 

[wtp]

like i said somewhere, it can't hurt to try.
maybe use a NOAA station.
i just don't know what radio,
and check for my PM

 

[wtp]

i hope i can get this right.
antenna cable center to one of the outside legs.
radio cable center to the center leg.
grounds on both cables tied together.

-/\/\/\/\-
........L

so the ends are the whole resistor.
the center swipes from side to side. (the L) (sorry about the ...but the L shifts to the left if i omit them)
so at one point it is no resistance (0 ohms)
and at the other it is maximum resistance.

 

[Planeguysexploration]

i hope i can get this right.
antenna cable center to one of the outside legs.
radio cable center to the center leg.
grounds on both cables tied together.

-/\/\/\/\-
L

so the ends are the whole resistor.
the center swipes from side to side. (the L)
so at one point it is no resistance (0 ohms)
and at the other it is maximum resistance.

Ideally yes

 

[wtp]

but in the pic you have electrically connected the ends together.

(resistance is futile)
so says the borg...

now for reality.
with it connected that way the best you can get is half the resistance.
so if it is a 500,000 ohm you can only get 250,000 and then it goes back towards zero

 

[Planeguysexploration]

But wait, if the wire is only connecting the ground of one coax to the other, and no signal is coming across would it really impact resistance between the wiper and first pin?

 

[Ubbe]

Will it work?

It looks like a reostat, a potentiometer for high power, maybe for a speaker, that are done by winding a coil over a ceramic body and the wiper goes over the top of the windings. That inductance are radio frequency dependent. To be useful the resistance for the potentiometer would have to be something like a 500 ohm type or lower down to 50 ohm.

It needs to be a shielded box with proper connectors on the coax. It will now receive all the interferences you have in the room.

/Ubbe