New spt500 gamma

[dave457]

That’s how mine came. It’s been up for a few months now with zero problems. SWR doesn’t change in rain either. This antenna
Is great. Will see how it does this coming winter.

So long did you end making it?

 

[Van Lifeson]

So long did you end making it?

22 feet 6 inches from the bottom of the black insulator (where the coax plugs in)
Not the coax connector bottom itself, from the bottom of the black insulator to the tip of the antenna . SWR is 1.3 across all 40 with or without the boot on.

 

[Ranch55]

For sure. I was just wondering if the long side or short side of the insulator faced the top of the radial plate. The manual seems to show the long side up but it came out of the box short side up

Long side up assembly for the upper insulator.
With the short side up, a direct "short" develops between the radiating element and the horizontal plate when it rains.
I am very sure about this. I have had "arcing" occur across that point even with the long side up.

 

[r carl]

Here is mine

View attachment 38108 View attachment 38109 View attachment 38110 View attachment 38111 View attachment 38108 View attachment 38109

You have the upper insulator upside down.

 

[Alexis Mercado]

You have the upper insulator upside down.

How is it supposed to look like ?

 

[Ranch55]

The longest end of the insulator is supposed to be positioned pointing up to the top of the antenna.
The intent is to have more insulating material on top to help prevent moisture from rain and heavy fog running down the vertical and having a "direct short", so to speak, to the radial plate.
That is why, shown in my photos above, I made a longer insulator from PTFE to overcome the "shorting" effect, and have a longer insulator.

 

[Alexis Mercado]

Thanks Ranch. I’ll fix it.

 

[r carl]

How is it supposed to look like ?

 

[Alexis Mercado]

Thanks Carl

 

[Marconi]

R Carl is right.

If you check his link closely and read the steps it is easy to get the top insulator installed as specified in the Manual.

https://www.worldwidedx.com/attachments/sp500-upper-insulator-pdf.38267/

At 0.17 seconds in the video by "More Jello Please" that Bob85 posted i the link below also shows the top insulator was NOT installed as specified in the manual. The fire ants were the least of the Jello man's potential problems.
Bob's post #6: New spt500 gamma

The image below, from Van Lifeson also shows the top insulator is upside down with the short side on top.

 

[Marconi]

Years ago I got an 5 year old HyGain CLR 2 antenna that was similar to the SP500. The antenna worked fine for me for maybe 3 years in the air.

When I finally took it down (still working) the top insulator was fine but the bottom insulator had small cracks around the bolt holes. I could tell there was some wear and tear from the radiator sitting on top of this bottom insulator. That mounting bracket design seemed strong to me.

My old HG CLR 2 antenna, as installed at the time, went thru a tornado that shut down parts of Houston...due to tree damage in the streets for several days. Even the top hat was was not bent. This old antenna is a strong antenna and several of the elements were taper-swaged with full compression clamps to secure the elements.

However, the bifilar type matching coil was made with weak copper ribbon tape on a small circuit board.

 

[Alexis Mercado]

Thanks Marconi for the info. Mine came upside down from the factory. I didn’t know it was wrongfully installed. Thanks to Ranch and Carl I could fix it.

 

[Marconi]

Ranch55, does you modification below fix the arcing problem?

 

[Ranch55]

Ranch55, does you modification below fix the arcing problem?

Yes, it does. That is the reason I did this. I did have an arching issue THROUGH the upper insulator.
The PTFE I used is rated for 500V per 1 mil of thickness in insulation value.....
No more arching, and no more climbing VSWR when the weather turns wet.....

 

[Marconi]

Good work,

Thanks.