(August 10th, 2014)

Shortly after having successfully tested the 2X8 RPOL, I decided to employ the same design strategy and upgrade to a 2X11 RPOL configuration in order to get more forward gain and a lower antenna temperature. One obvious challenge was that without being able to install guy wires as the boom and the elements need to be able to rotate, it was critical to make the antenna ultra light without compromising its overall strength so it remains straight, and not load too much weight on this long "unsupported" boom.

I opted for a construction which uses very light yet, super resistant fiberglass for the boom. 75% of the boom length is made of that fiberglass and 25% of the boom towards the rotator is made of alumimum to provide a strong enough structure that connects to the rotator pipe. All the elements are light and located far enough above the boom by a non conductive plastic clamp so no boom corrections are required.

The resulting antenna system is extremely light yet, very robust where it remains straight without a single guy wire. There is no conductive material between the 2 bayed antennas which could negatively influence and distort the radiation pattern (wires, stacking frame, etc.). Everything is "far behind" the reflector element which helps producing a clean radiation pattern as there is "nothing in the way".

Pictures below of the antennas ready to be put up, and the fully assembled setup on the roof:

Front View:

Rear View:

Street View:



***WARNING: For Best Resolution, it is critical to select 720p HD resolution in the youtube "settings" at bottom right of the player. The 360p default setting won't yield good enough resolution to see the details. It will take several seconds before the High Resolution kicks in, so you will need to restart the video from the beginning when the High Resolution is active and select to view the video in "Full Screen Mode" for best experience...***

The very day after having setup the 2X11 RPOL, I worked 2 Single Yagis within minutes. One was 1X18H/800watts and the second one was 1X17H/200watts. The RPOL was invaluable in the later instance where the QSO started at 45 deg polarization, the trace was lost mid-QSO and was finally recovered by rotating 15 degrees clockwise in order to catch up with Faraday rotation and recover a precious dB that was needed in order to wrap up the QSO...


8 out of the first 11 QSO made with the 2X8 and 2X11 RPOL systems were with low ERP / small stations. See below the list:


Antenna System Power (watts)
1X12 600
1X17 200
1X18 400
1X18 1500
1X18 800
2X9 800
2X9 NA
2X10 1000


The overall performance of this new antenna system has been absolutely fantastic so far and has tremendously enhanced my EME experience and made it even more enjoyable. Rotatable Polarization (RPOL) has enabled me to be much more "efficient" and "effective" with my time, where I no longer need to wait long hours or miss out on a good moon window or DX due to Faraday's tantrums. RPOL allows being able to take advantage of every watt of power delivered to the moon and not having them being wasted due to polarization mismatch.