Voltage to Winegard head?

[truxpin]

Started having an issue with our (up to now, perfectly working) Winegard antenna on our '01 Limited. Pulled the head off the mast & opened it up, finding it very dirty inside )including wasp nest's & mud dawber nests.
Completely disassembled the head & cleaned it all up. Pulled the wall plate & checked the outgoing 12V signal with a short piece of cable & connected the head unit to my test cable & ran auto-program on the TV & it worked perfectly! Even pulled in 41 channels with the head inside the Airstream!
Put the head unit back on the mast & suddenly the reception is crap again....
Checked the voltage coming through the cable at the mast & found it to start at about 12 volts only to steadily drop to about 7.5 volts. I'm guessing this may be the problem? Only I'm left wondering what could cause this? My guess is an issue with the cable? I figured I'd pull a new one, but it seems the original one may be attached or bundled with other wires inside the walls/ceiling because it doesn't have any free movement in it when i attempt to pull on it?

Anyone have any ideas, what would cause the voltage drop in the existing wire? I find it hard to believe the original cable is broken anywhere inside the walls, but am left with few options.....
Thanks for any info....

[ROBERT CROSS]

Have you removed the boot that goes thru the roof?
There is a connection under the boot to the inside cable.
I sealed the roof this past spring, including the antenna base and boot... when I tried the TV we had nutt'n.
I suspect I disturbed something, but never got around to fixing it.
To be honest...TV is not all that important in the AS. Kind'a nice that it was left behind this Season.😂
When it's time I was thinking of an up-grade.

Keep us posted...be good to know what you find.👍

Bob
🇺🇸

[truxpin]

Well,

After an hour or so, I talked myself into just pulling a new coax cable, fortunately I started on the easy end (ceiling penetration)
To my surprise, after yanking about a foot of slack out of the ceiling I came across a "wad" of cable taped together with a very sticky duct tape. I unwrapped it all & found a VERY corroded junction. It looked like they used a double female end coupler in between the line from the wall box & the mast itself. It was so bad that the male ends didn't even have the copper "male" line sticking out of the connector. Completely corroded away. Kinda makes me wonder how it functioned at all. I snipped the whole mess out & replaced with new ends and replaced the line going up to the mast , as it has seen it share of UV rays & visually looked terrible.
Also, because I jumped the gun a bit, I replaced the Winegard head with a new King Jack replacement head that I had already bought & had sitting there when I found the real culprit!
I must say it works so well, I don't have to raise the mast to get our local channels. (We're very close in town) and works with the Winegard OEM booster existing in the wall. It's considerably smaller than the Winegard & that'll take some getting used to.