Due to various reasons, restricted space and laziness I had no proper antenna available for 10M. Until now, I have used my 40M dipole and used the ATU to match the horribly mismatched antenna to the transceiver.
Today I made a very simple half wave, rotatable dipole from aluminum tubing and mounted it on a mast 7 metres high (21 Ft). This is only 3 metres (9 Ft) above the roof of the house. The dipole is directly fed with some old RG-213 coax I had at my junk box.
The difference in performance is huge. On average the signals are 4 S-points higher during fast A/B switching between the old and the new antenna. This translates to a 36 dB improvement. Even more convincing proof is achieved, by monitoring the Reverse beacon network. I could only manage to get spotted on the old antenna if I used power well in excess of 100 watts. I am now able to generate a few spot’s whilst running QRP (5 watts).
Unfortunately, with this improved performance of the antenna, the noise floor has also increased. I suspect I will get a better signal to noise ratio, if and when I raise the antenna a bit higher than what it is at the moment.
I am now finally convinced that it is essential to use resonant antennas. Using the ATU to force a match to a non resonant antenna is not very effective and should be avoided.
The screen shot below clearly shows the difference in performance. The spot made by VK6IA and PJ2T were achieved with 5 watts, all the remaining spots are done with 100 watts and the new dipole. I am not able to get spotted at all with 100 watts and my old non resonant antenna.
Now imagine, if only, I had a multi element Yagi up at 100 Ft…….
73 de Pierre ZS6A