[TowerTalk] A3S SWR Problem (kinda lenghty)

[Joe Reisert]

Mike,

If it's like other Cushcraft tribanders with the 40 meter extention, the 20
meter trap used for the 40 meter section is defective or has been smoked. I
smoked 3 of them at 400 watts and finally gave up and removed the extention
kit. All you have to do is remove the 40-meter extention kit and go back to
the old triband configuration. All you'll lose is 40-meters.

When I removed the defective 20-meter traps, they had a terrible pungent
odor from burning RF! When removed and examined internally, the screws
holding down the coil wire on the hot end had been GROUND OFF during
manufacturing! Therfore, when the antenna flexed, the connection became
intermittent and eventually burned across and melted the end of the trap.
You know the rest of the story. Very poor manufacturing indeed!

>In the week between xmas and the new year (thanks to George, W1ZT for a 
>tremendous amount of help), my tower went up and the A3S with 40m extension 
>on top of it, but now I am experiencing some problem with the antenna that 
>I need advice for.
>
>The problem is basically that the SWR on 20 & 40 is terrible, and it 
>fluctuates in an odd way. On 15, it is ok sometimes and off at others. On 
>10m there seems to be no problem. Here's a detailed description of what's 
>happening:

In my case, I went up the tower in the cold part of January (10 degree
weather) since I wasn't going to go off the air. The driven element was
close to my mast. I loosened the U-bolt and rotated the driven element
until one end was close to the tower and used my nose to sniff the 20-meter
trap. The first one was OK so I rotated the dipole the other way and when I
sniffed this trap, PHEWWWW, did it smell! Culprit found!

>Has anyone seen this kind of strange behavior before? I'd like to have some 
>idea what to look for before I recruit help to get the antenna down and 
>start tinkering with it. Maybe the best idea is to just buy a new A3S and 
>bring the used one to a fleamarket - clearly an option if I put a price on 
>aggravation.
>
>Thanks de Michael, K1JE
>

Good luck. Hope this helps.

73,

Joe, W1JR


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