Can someone suggest a good 50 to 75Ohm impedance matching transformer?

[D0T-C0M]

I use a FM transmitter in my truck and would like to use a normal FM antenna to transmit the signal. I think I will need a RF impedance matching transformer that will match the 50ohm impedance of my transmitter to the 75ohm impedance of the FM antenna. Can someone please suggest a good one that I can buy or if it isn't too difficult I would consider making one.

Am I correct in assuming I would lose about 1/3 of my radiating signal if I directly connected the 50ohm FM transmitter output to the FM antenna?

Does it make a difference where in the circuit I put the matching transformer? Should I connect it as close as possible to the FM transmitter and run 75ohm cable to the antenna OR should I place the matching transformer as close to the antenna as possible and run 50 ohm cable to my transmitter? Or does it make a difference?

Should I be concerned about the change in temperature in regards to the matching transformer which I understand is temperature sensitive to some extent?

Thanks as usaul for all your help.

 

[audioguru2]

Hi Dot-com,
Isn't your FM antenna just a whip? It impedance is affected by the size of its ground plane and anything that is near it. It might already be 50 ohms.

A transformer will have some loss. The loss will be about the same as a small amount of loss from the impedance mis-match so you gain nothing and you won't be able to measure the small difference in output power caused by the impedance mis-match anyway.

 

[D0T-C0M]

Ok I was told the the impedance of the stereo antenna in my truck was 75 Ohms, so I thought maybe I should match the impedances because initially I thought the signal loss would be roughly 2/3 of full power but I read up on the net while awaiting your response and I guess the signal loss from the impedance mismatch varies with the length of the wire. The wire in my truck is very short so I guess I won't need a matching transformer like you suggested as the signal loss will be mimimale.

Audioguru, Thanks very much for replying.

D0T-C0M