Tag Archives: Vern K9EME

Replacing an old T-8 with a new Tennadyne T-8 at the K9ZW home QTH

[December 10th, 2017 – releasing this post that somehow never was added back in September]

 

What does a log-periodic (LPDA) antenna look like when a combination of wind-fatigue, corrosion, and some issues from a nearby lightning strike all come together?

 

The old T-8 after 20+ years of abuse missing elements and with broken boom-element interfaces.

 

The Old T-8 Being Abuse by Winter

My old second hand T-8 had seen better days.  Coronal arcing was from a nearby tree lightning strike.  Corrosion was caused by the previous owner having injected elements with some sort of spray foam sealant.  And the wind was the 20+ years of exposure, including some recorded high speed prolonged winds.  Sort of like driving the antenna at freeway speeds from here to Chicago and Back.

Vern K9EME was instrumental in changing out the antenna, as I had some very restrictive health limitations at the time.

 

The new improved T-8’as it was being assembled on the tower

 

We had a snorkle-lift to use and the replacement went very well.  The reason we assembled the elements after the booms were installed was how easy the lift made the work.

Also replaced was the choke-coil and feed line.

Again with many thanks to Vern K9EME, the K9ZW station returned to the air very quickly.

The corrosion that had set into the old antenna along with the effects of the lightning strike to a nearby tree made the old antenna a candidate for recycling.  No amount of effort could separate parts of the antenna, and other parts were powder.

Despite the abuse it had really earned its keep.  I really didn’t want to change it for anything else.

Since he took over the company,  Roger at Tennadyne builds his new antennas with MUCH thicker boom material, better clamps and hardware – all resulting in a new T-8 being a significant upgrade.

73

Steve
K9ZW

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Projects at the K9ZW South QTH – New AlfaSpid Rotor

It is maintenance time at my home QTH. Fixing storm damage, wear and tear, doing preventative maintenance and replacing broken things.

I’ve had some serious help from Vern K9EME in the work. Actually too often it must be admitted I was watching as Vern K9EME took care of the work.

A high energy strike nearby (I think it was when a nearby streetlight was “smoked” by lightning) had finished off an increasingly unreliable rotor, taken out the half-sloper, and I had some damage occur at the same time to the larger Log Periodic antenna, with one element suddenly impossibly drooping.

Fixing the half-sloper was easy. The solder from the main wire to the connector was gone – simply burnt away, and soldering things back together and inspecting took care of that problem.

Swapping out the rotor, an old Ham-IV for a new AlfaSpid RAK was a real challenge.

This tower is a Tri-Ex LM354 and is a motorized crank-down with manual tip-over.

Here is the new rotor going into place:

AlfaSpid RAK replaces Ham-IV

AlfaSpid RAK replaces Ham-IV

 

The AlfaSpid RAK rotors I have all came from Alfaradio.ca in Edmonton Canada. The units are built in Poland, are a very different design than the typical small ham radio rotors, are unfortunately a bit pricey but offer great precision, high reliability, better capabilities and more precision.

Here is a bit closer what it looks like:

 

The AlfaSpid RAK up close

The AlfaSpid RAK up close

 

It was challenging work to get everything sorted and K9EME’s experience made all the difference.

As there was very heavy duty eight-wire rotor cable in place, we wired the four-wire AlfaSpid with double wires on the sensor connections.

After verifying everything with a multi-meter we photo-documented how we wired it:

Photo-Documentation is a Good Thing!  RAK wiring up close

Photo-Documentation is a Good Thing! RAK wiring up close

Cannot tell you how useful pictures are when years later something needs fixing or replacement.

Getting the Greenheron controller operating with the AlfaSpid didn’t go well, and I called Jeff at Greenheron who quickly help me figure out the protective TranZorb diodes had been fused along the way. A quick temporary fix and all was well and replacement diodes were ordered online.

The Tennadyne T-8 is actually missing a bit of the square boom at the lower longest element. I have a call into Tennadyne for the spares, but it is hunting season in Michigan and Wisconsin, and I got the answering machine,

I have a concept for a repair that should stand up for now. More in another post.

I’ll spare sharing the inspection and PM, but when you have a tower down and over it is a good time to do a full service.

73

Steve
K9ZW

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