Whip antenna connection to a RF preamp circuit

[deepak007]

hello

i have a small doubt. i have a rf preamp circuit which an antenna input and an output connection. each connection has two wires antenna and ground.it is designed for dipole. if i use a whip antenna. how do i connect?

 

[vfone]

Re: antenna connection

If was designed for a dipole just connect one wire to the ground and the other wire to your whip antenna.

 

[deepak007]

Re: antenna connection

if i want to use a whip instead of dipole, can i omit the ground connection?

 

[Eugen_E]

Re: antenna connection

You should be careful so the output of the amplifier is terminated on correct impedance, and use coax cable and connectors.
If you have loose wires in RF, and the whip antenna is near, also connected with common wires, the amplifier may oscillate, because the antenna will couple back the amplified signal, resulting in feedback and oscillations. This is true especially if the amplifier has a high gain and uses UHF/SHF transistors.
A groundplane antenna is more correct.

 

[flatulent]

Re: antenna connection

If your antenna has an even remotely 50 or 70 ohm impedance, you will benefit from using the amplifier if it near the antenna. This will prevent the transmission line loss to your receiver form causing harm.

However, if you are listening to high power broadcast transmitters, the use of this amplifier is a moot point.

 

[RF-OM]

Re: antenna connection

If you are in TV or FM broadcast band the best way is to use TV balun (e.g. from Radioshack).