I am kind of surprised that RV manufacturers are still installing the Winegard Sensar crank-up type antennas. They are problematic, prone to leaking, and you have to remember to lower the antenna before leaving the campsite. To be fair, many RV mfgs are no longer installing the antennas, but too many still are. I also have some issues with the coax, at least the coax I can see. It doesn't appear to be installed correctly, with very sharp radius bends, and possible staple damage.

So in this project, I am getting rid of my crank-up as it has leaked on occasion (yea, I know you need to lubricate the o-ring occasionally so this does not happen), but why even have an antenna where leaking is possible.

The two antennas I am considering are the Winegard Razar Automatic (RZ-8500 series) and the King Jack OA8500 antenna. Of the two, the Razar is around $300, which is about three times the cost of the King. The Razar is available in White or Black, as is the King. And the King is available for a new install, or a retrofit for the Sensar antenna. However, you still have the leak-prone issue so that is really not a solution.

There are a couple of considerations when installing these antennas. One is how close you can place the antenna to the side of the RV - especially for retrofit purposes. For the Razar, the manufacturer recommends no closer than 12", and the King recommendation is 8". This is a critical measurement as otherwise, the antenna can be blown off the roof as you are going down the highway - and in the last year or so, I have seen at least 3 King antenna heads lying on the side of the highway.

Another consideration is patching the roof. The Razar comes with a metal mending plate, while you can purchase s PVC plastic plate for the King. One irony is while the Razar comes with the metal plate, the instructions do not recommend installing the antenna over anything metal for performance issues... what? You provide a metal patch, but can't install the antenna on top of it?

As well, the Razar Automatic did have some reliablity issues in 2016 with many units receiving an E3 error, which happens when the azmuith motor draws too much current. Apparently that issue has been solved as I have not seen any complaints for the E3 error in 2018.

As well, if you read every review on the internet, you would never buy anything. At any rate, I ended up choosing the Razar as I liked that is was lower to the roof than the King antenna, and there was nothing under the antenna head to catch on a tree branch.

When I removed the old crank-up antenna, I came to realize that neither the Razar metal patch or the King retrofit patch would fit over the section of the roof with the holes in it. As well, it rather looked like the factory simply cut a slit into the rubber roof, then bashed a hole into the plywood roof underneath. I ended up patching the area with Eternabond tape, which looked horrible, but at least sealed the roof.

I have to also point out that one of the aftermarket roof spray-on coatings do not recommend using Eternabond, as they say moisture can wick through. I do find that hard to believe though, and I have to take their statement with some skepticism as they are competing more or less with Eternabond.

At any rate, the hole I patched with Eternabond has a cover plate on the interior ceiling, so I can monitor the patch to see if indeed any moisture seeps through. But I rather doubt it will happen.

So I had to custom make a patch, which a year ago would have freaked me out. But I already have two patches in the roof - one from a RV dealer; I took the RV in for repairs, and a month later when I had to take the RV to a second dealer to fix the repair the first dealer failed to do. After the second repair trip, I discovered one of the dealers gouged the roof, so who do I blame?

And I found a pin-hole in the side of the roof, and I am not sure how that happened. One day perhaps I will have to have the entire roof replaced, but until then, I'll be keeping a roll of Eternabond handy.

For the patch, two materials are readily available; HDPE (High Density Polyurethane), and PVC (Poly Vinyl Chloride). Of the two, HDPE is not necessarily UV resistant (you can buy some that are), is brittle (it can crack), and virtually nothing sticks to it. While painting the HDPE can result in UV protection, paint doesn't adhere all that well. And, I also had some concern with the lap sealant attaching itself to the HDPE.

I used butyl tape on the underside of the patch for good adhesion to the roof, screwed it down with about 20 screws, and then applied lap sealant. Hopefully there will not be any condensation issues in the future, but it's sealed rather well, so hopefully not.

According to the installation instructions, the dome must be at least 12" from the side of the roof, and 24" behind the front of the roof. This is to prevent the wind whipping up the side or from the front knocking the antenna off the roof as you are traveling down the road.

I have personally seen several antennas lying dead along the roadside (not a Razar Automatic though), and I can only wonder if they blew off because a manufacturer did not heed this warning (some look very close to the edge).

I suppose though that the taller antenna types might become dislodged somewhat from a tree branch that might have assisted in taking out the antenna.

Although Winegard did not provide any details, I am thinking the most conservative approach to this rule is a flat roof like that shown to the right.

As the RV goes down the road, air would tend to collect at the front of the coach, with the roof behaving like a spoiler of sorts to divert much of the air up and over the antenna. In this scenario, the only air hitting the antenna should be from directly in front.

This is of course conjecture on my part as I do not have access to a wind-tunnel to determine this, nor did Winegard provide any details (I had to call tech support just to find out why there was a 12" side/24" forward location restriction).

While I meet the 24" forward location restriction, my roof is sloped. There is a slight dip in the roof for the 60" forward of the antenna, with a bullet shape nose that extends 36" further. The slope is not drastic, perhaps a slope of 8Deg.

So my hope is with the slight slope coupled with 60" of distance, there will not be a lot of wind resistance coming up from below the RV, especiallg given the bullet-shape of the nose (both horizontal and vertical planes).

Regardless, driven by my conservative approach to projects, I will be strengthening the attachment point for the front foot of the antenna.

There is a rafter very close to the front foot of the antenna, however, I purposely did not sink screws into that area because it is made from Pine, and there is a real chance of cracking it if not pre-drilled.

And unless you use absolutly large fasteners such as Lag Bolts (not easily found in smaller diameters), or wood screws (typically brass, which is a weak metal vs steel).

I always like to use Stainless Steel hardware, and the only screws I could find were sheet-metal screws, which do not have the larger thread surfaces that wood screws have. That means their holding power in Pine is not great - regardless of the thickness.

For those reasons, I shoe-horned in a "Cleat Block", which was a 3/4" thick piece of Oak, 18" long x 6" wide. It was not easy, but I finally managed to get it positioned correctly - then sunk 3 #12 x 2" sheet metal screws into it. Oak, unlike Pine is farily dense, and will hold the screws a lot better. I also had the choice of using Hickory as that was also available. But Hickory is almost too hard, and I have actually snapped screws off - even when drilling pilot holes.

Hickory would have been the wood of choice I suppose for holding power, but as hard as it was to work on, and under the roof, I did not want to contend having to deal with broken fasteners. I don't think that antenna is going anywhere.