I have a strange problem with 2 slopers. Apologies in
advance for being a bit long with this...
For the last year, the only topband xmit antenna I've had is a
1/4 wave sloper (actually a W9INN 40/80/160 loaded sloper),
which is about 55' long, fed at the tower at 50' up.
In an effort to improve xmit, I decided to put up a
full length (~130') 160m sloper, also fed at the tower,
about 48' up and several feet to the side of the feedpoint
of the other sloper. (Yeah, I know, slopers might be
so-so, but I'm doing what I can...)
Both of these, as well as the HF & 6m beams, go through
an Ameritron RCS-8V (5 port) coax switch which is also at
48' up on the 64' Trylon.
As I was adjusting the new full-1/4 sloper, getting tuner settings
written down, I started to write down amp plate/load settings.
After a few minutes of this, my SWR jumped WAY up. I figured
the string broke or something. I went out, and the new sloper
was fine, but the old 40/80/160 sloper had lost its rope and had
swung down so the end of it was at the base of the tower.
Odd -- so I put it back up and went back to amp tuning.
It happened again, so I redid it. The third time I used new rope.
The 4th time, I thought some antenna devil was wreaking havoc.;-)
After the 5th time, it was plain that the egg insulator at the bottom
of the old sloper had started to melt and the rope (nylon) had
melted through.
Note that I was xmitting on the new long sloper, but my old
loaded sloper is what melted at the end. They go off in different
directions, probably 70 degrees apart. I thought the coax relay might
be stuck on the port for the old sloper, putting it in-line all the time,
but ports 1 and 2 (for 6m and HF) are functioning with normal SWR
on 6m-20m, and if the old sloper relay was stuck, I'm pretty sure
I'd notice some anomalies on those bands.
This is the first time I've used port 4 on the switch, so I could
have bad wiring (port 3 and 4 together), but I was careful with
that wiring. A continuity check of the control lines do not show
the wires for ports 3 and 4 having a short.
Or, could 1kw on 160m be causing the RCS-8V to be flipping
relays, since the new sloper feed is only 2-3' away
from it? This is just plain strange (and unexpected), so I'm
kinda at a loss... I just don't see how my old sloper would
be melting its end insulator when I'm using the new sloper!
As always, comments appreciated.
--
Dave NØRQ
_______________________________________________
Topband mailing list
Topband@contesting.com
http://lists.contesting.com/mailman/listinfo/topband
|