can an antenna effect the range of rf transciever

hi,
can anyone tell me that how an antenna can effect the range of rf transciever.if i am using rf transciever of 3000 ft range is it possible that due to antenna the range reduces to 250 ft only?

Before i write my answer, i would expect you to clear some of my doubts by answering my simple questions mentioned below.
How it was concluded that the actual range of the said transmitter is 3000 feet?
Is the transmitter a Home made one or a Commercial make?
What volatge is supplied to the same?
What current it consumes while tranmitting?
What antenna are you using now?
What type of wire is connecting between the Antenna an dthe transmitter?
Is any matching used?
Is the SWR measured? IF yes, What is the reading?

Cheers

If there is a very poor antenna the link can be decreased even to one foot, but in the same time if is used a very good high gain directive antenna the link can be increased several times.

The antenna is part of the link budget of the RF system.

For example to lose 3dB on antenna gain is very easily (due to mismatch, nearby environment, etc), but to increase the transmitter power with 3dB (double the power) is very hard.

A system that might transmit 3000 feet outside, with no trees, bushes, buildings, etc in the way, could easily only work to 250 feet if you are inside a building, or if there are lossy or reflective obstacles in the way.

The antenna might be broken, or there could be other issues (extra system noise) that are hurting performance.