Give a little help to your tuner

Telescopic fibre glass fishing poles are very popular among QRPers. All we need is a piece of wire, a tuner and a telescopic rod to be on the air. The weakest chain in the system is the tuner. Unfortunately it can be lossy enough to "eat" our small power. Impedance of random wire antennas are not predictable. Nobody can tell how they will behave on a top of the hill. If the impedance is too high the L-match tuner will dissipate the RF power as heat. Transformers are more efficient, but not tunable. Using both together is very useful. 

How do I know if I need a transformer?

First we need a field strength meter. You can find a working one below in this blog.

Connect the un-un transformer to the output of your tuner, than tune the antenna with and without the un-un. Check the field strength to see what version provides better signal. The difference is clearly visible. 

I made transformers with 1:4 and 1:9 ratio with a small switch to select the suitable range. Sometimes the difference can be even more than 12dB. Using only 1-2W it is serious difference.

The QRP version with switch on the side.
(frequently in use)

The QRO version for up to 300W.
(collecting dust on the self):)