[MAMS] Wind, spinning yagi's

[Zack Widup]

Great advice Lloyd! Do you know where N8PJP got the 70 foot extendable
mast? Is there something like that currently available that doesn't
cost an arm and a leg? Maybe I could build one? I'd settle for 30 or
40 feet. I don't think I need to go up 70 feet, at least on a hilltop
where there are no trees, just corn and beans

I usually put up two masts when portable on all bands in a contest.
One has 50, 902 and 1296 on it and the other has 144, 222 and 432. The
other bands are from the dish on a tripod.

If I ever get a truck or van I have some ideas for antenna mounting.
But for now it's the Corolla and I don't think I am going to mount the
antennas to that unless I get a roof rack and do something like W9SNR
does. That's pretty impressive, too. The only drawaback is that you
have to rotate the car to rotate the antennas.
:-)

73, Zack


On Tue, Apr 5, 2011 at 1:28 PM, Lloyd Ellsworth <l10368r1 at gmail.com> wrote:
> Got reading this train. Some comments. Hey, lots of advice. Some I
> actually use.
>
> What I learned years ago with big HF DX antenna arrays. You can't
> really tighten them clamps enough to stop them from windmilling. Pin
> them. Get them properly set up. Get out the drill motor, blast a hole
> and then pin them with a bolt. Ya, not in the book. Ya, the holes will
> eventually elongate. Cracks form too. Then the added stress. And
> eventually lead to self destruction. Price of gain. With my rover
> array, all the hours of 70 MPH winds, They are all pinned. Keep them
> put. Then I add some guy ropes. Well, string. Then at each stop, level
> the array. Keep those antennas on the horizon. In 12 years of use,
> only lost one pinned yagi.
>
> Look at 3 more concerns.
>
> First. More clamps? If you have an end mount antenna, no big deal. In
> the middle, you have a larger lump of metal, that could potentiall
> help detune it. Loss of gain. They will still windmill. Then wind
> pressure out of verticle.
>
> Second. 5 sections of RS tube. Wind pushes entire set up, out of
> verticle. Even with guys. That includes many towers. Meaning antenna
> is not looking at the horizon. Which require a pile more weights,
> guys. Stuff to haul. Extra time to set up. Tear down. Not to mention
> all the room they would require. These days, how many more gallons of
> fuel. 20 years ago, N8PJP rover, built a nice trailer, with a 70 foot
> extendable mast. As a VHF rover, worked great. Got over many of the
> trees. 6 through 1296. On the ground, such as the Lake Shore, it is
> nice to have an extra body, set of hands. to hold a large dish or
> antenna in place. Keep it on the horizon. Or where it needs to be.
> Rover drivers are great for this.  If your YL, MYL is willing. Works,
> but usually there is an exchange involved.
>
> Third. Weight and occupied space vs small rover. Ya, in the winter, I
> use a couple of sandbags. So, yes they are available for me. Usually
> not expensive. Commonly available. OK, pick up here. I don't use
> sandbags for the antenna stands. Bulky. I use 12V batteries. One
> painful lesson learned early on. Always have extra battery power
> available. Better to invest the extra bucks in a couple of extra
> batteries. What can I say about keeping an eye open for sales? Usually
> solves 2 problems. I use a car battery, in the shack. Yes, with
> ventalation. then some wood, to protect against the acid drip. Part of
> my test set up. Checks out the battery performance too. For smaller,
> more fuel efficient rovers, space is a critical consideration. If not
> the most important. How to best use available space. Then there is the
> no holes, scratches etc issue. Lucky to run a piece of RG58, foam, in
> the door. For the magmount. Then comes efficient packing, unpacking.
> Setup and tear down time. Then as many know, the ideal goal is 3 to 10
> minutes, during a contest. Becomes an art form.
>
>
> 73, Lloyd NE8I/r
> EN74 etc
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