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Very Basic FM radio help

davenn

Moderator
Sep 5, 2009
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Sep 5, 2009
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Attenuator pads as shown above can be used for any signal, audio, video, RF.
In the Pi network, Rp1 and Rp2 will have the same value
In the T network, Rs1 and Rs2 will have the same value.

For any given line impedance Z (more correctly Zo = Characteristic impedance)
the values selected for the 3 resistors will give xx dB of attenuation.
A number of www sites have online attenuator calculators

cheers
Dave
 

davenn

Moderator
Sep 5, 2009
14,254
Joined
Sep 5, 2009
Messages
14,254
tried everything and was about to buy a 300 Ohm split cable

ya know you can make really good folded dipoles out of 300 Ohm ladder line !!

when I have time i will post a diag :)

tis now time to fly to brisbane again for a few more days :)

Dave
 

KJ6EAD

Aug 13, 2011
1,114
Joined
Aug 13, 2011
Messages
1,114
You have to use a switch to select or bypass the attenuator so it doesn't affect the weaker stations. On many small portable radios, this switch has two positions labeled DX (distant) and local.
 
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