vrijdag 13 juli 2012

Steppir after 7 years - general maintenance

Last week I did a complete check of the tower and the antennas on it.  Especially the steppir always takes my attention because of the risks that go with it : 12 control cables, many parts in plastic or rubber.
The bad news : one of the six rubber connectors shows a fault line.
Steppir rubber connector attacked by the sun
Steppir rubber connector after taping in
The good news : this has not been changed since two years.  I detected this for the first time two years ago and since then,  I taped all rubber blocks.  No more bad changes in the structure were found.  This wear is mainly caused by UV light.  Now with the tape on it, the sun can't attack the rubber anymore.
No problems detected on the 12 conductor control cable.  Ouf...

Second change : reform the 30m optibeam dipole to a 40m dipole.  Simple job : just change some tubing.  I also added a 1:1 balun to avoid mantle currents.  Installation on the typical on4ccp method : tape and plastic bindings.  Certainly not following the correct mechanical rules of attaching things, nor using the special stuff provided by dxengineering, but it works (since 17 years I used almost only plastic tape and bindings).

The only thing that concers me is the 90 degree connector that I had to put on the bottom of the balun in order to obtain a sufficient coax loop for the rotor.  The space under the balun became to limited to connect the coax directly. I had no other option unless reinstall both antennas higher on the tube.  With all the rain, this seemed too much work, so the extra connector was used.

Third change : replace all RG213 by Ecoflex10.   The complete coax chain exists now of Ecoflex10 and 7/8" hardline, both for power handling and low loss reasons.  Replacing the connectors took a lot time i.e. connecting a N-connector to Ecoflex (same as Aircom) is very easy and can be done without soldering and in a very short time.  But connecting a PL connector to Ecoflex was a hard long job.  I've experienced many problems to conduct the core cupper into the connector.  The 7 cupper wires must exactly fit into the connector hole.  A bit too much force and there is always one wire bending.  Restart from 0...

Finally, one of the main reasons why I'm such a supporter of the steppir antenne : turning over the tower is very easy with the fiber tubes.  On one side I can insert the 3 fibers so to tower can hit the ground without the need of a ladder.








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