Tennadyne T6 LPDA

In October 2010 I replaced my old Fritzel FB-33 tribander (20/15/10m) trap Yagi with a Tennadyne T6 6-element LPDA (Log Periodic Dipole Array) which worked very well and offered no-tune coverage continously from 14 to 30 MHz. The antenna resided 15 meters above ground level on the top section of a Versa-Tower which is mounted on top of an unused chimney. This chimney contains a reinforcing steel tube and is filled with concrete all the way down to the basement of our house. A lot of work had to be done before I could take the following picture from an attic window.

But it is history. Unfortunately it was downed, not by a heavy storm but by tiny solitary bees: they had nested inside the element tubes, but instead of using clay as usual to build their nests they obviously used mortar which they collected from a nearby construction site on our neighbour's plot. The result was devastating, because the mortar caused severe corrosion from the inside of the aluminium tubes. Finally their walls were so thin that elements simply broke off, so that in spring 2022 I was forced to dismantle my T6 ...

After dismantling the old antenna, I cleaned and re-painted the top-section, installed the new antenna rotator Create RC5A-3 with the UC-1 universal coupler plate, the CK-46 mast bearing and the stainless-steel supporting mast assembly. The result is shown on this picture. Note the tiltable joint in the mast assemby - it plays a vital role since it allows final assembly of the partially assembled antenna on the roof.



A close-up view of the rotator and coupler plate. The tower top-section is welded to a 1" thick steel-plate covering the chimney.



Emirates Airline brough my T6 from Toledo / USA to Frankfurt / Germany. After inventory of all antenna parts on the basement floor ...



... I pre-assembled the four boom-sections with only the two inner sections of each element ...



.. and brought these four pre-assemblies up to the balcony to put them together - this is the result.



Now this assembly was mounted on the supporting mast ...



... and subsequent tilt-and-rotate allowed me - standing between the chimney and the roof - to reach the pre-assembled section ends in order to install more and more tubing sections.



The T6 comes with nothing but two holes and screws to attach coax at the feedpoint, a solution which is not good at all ! So I constructed this weatherproof feedpoint-assembly with sliding hood from aluminium stock, PCB material, an SO-239 connector, stainless-steel hardware and grey perspex.



This balun-assembly was constructed in the same fashion - the balun is a common-mode choke made of 7 turns of RG-58 coax on two stacked Amidon FT140-43 toroid cores.



The feedpoint-assembly with hood, installed at the boom end with the shortest element ...



... and the balun-assembly still without hood, installed at the boom-mast insulator. Except for the balun windings Aircell-7 coax is used.



All elements, the feedpoint-assembly, the balun-assemby and the shorting stub at the boom-end with the longest element are installed now.



This is my plastic crow named "Karl-Theodor" (after Germany's former defence minister Karl-Theodor zu Guttenberg) - he defends the T6 against pigeons and 8 months after the installation I can say that he does an outstanding job, since I have never seen any pigeon sitting on the antenna ;>)



A view over my hometown Pforzheim, standing on the chimney below the T6 heading North.



... mission completed !



This is the roof of our house with the Tennadyne T6 LPDA installed on the chimney and the Titanex V40 vertical on the balcony. My radio shack is the corner-room behind the steps with a door to the balcony.