[TowerTalk] Small mast advice

[jimlux]

On 11/10/20 4:50 PM, Richard (Rick) Karlquist wrote:
> 
> 
> On 11/10/2020 3:40 PM, Ross Tucker wrote:
> 
>> the RV park, she can't lay concrete or have excessive guying. I know this
> 
> Get one of those base mounts that your drive your vehicle on top
> of.  That is just about as good as concrete for this purpose
> and the RV park can't say any thing.
> 
> For guying, "bracket it" to the RV with guy wires that
> run along the roof of the RV then down the sides.  Again,
> the RV park can't say any thing about these, and they
> will be at the roof height of the RV.
> 


If your RV has a roof rack or a ladder, then you can use a ratchet strap 
or similar from that to the mast.

You can develop significant wind loads, so actually, the wheel on top of 
a plate thing is great, because it has a well defined failure - the mast 
falls over, but doesn't rip the rack off your roof.

I was working on "rapid field masts" with my VW Passat a while ago, and 
I quickly found out that putting a mast up 15-25 ft, with a bit of 
antenna on top and you can exceed the 50-60 lbs the rack can take as a 
lateral load.

It's because there's a nice lever arm (5 ft to car roof rack, 20 ft to 
antenna, gives 4:1 advantage.. ).  On your RV it will be better.

I've also built antenna mounts that hook into the hitch socket.

one thing to think about - a larger diameter aluminum tube is stronger 
than a small diameter steel pipe, and a lot lighter. It's sort of a 
tradeoff between storage space and wrestling it around. 15-20 ft of 
steel fence top rail is a chore to move.

I've been pretty happy with the 40 foot collapsible carbon fiber masts, 
and using them up to 20 ft with a moderately heavy thing on the top. 
But they are flexible.