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VHF/UHF mobile antenna on motorhome

Mar 19th 2015, 06:13

K6SDW

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Hey all.........so, my wife k6sew won and we bought the "bus" a 39' motorcoach....or, as I call it, the BUS!!!

I've installed my Yaesu 7800 vhf/uhf rig near the driver and plan to use the ladder at the rear of the bus for an antenna mount.

Any thoughts here? My concern is that at 12.5' roof height of the bus, most any antenna mounted at the top of the ladder will be subjected to physical harm, as in low tree branches, freeway overpasses....etc...

I'm considering buying a VHF-only whip since in this part of the world, the military's PAVE-PAWS has pretty much screwed us out of using UHF...I'm hoping the selection of a VHF 5/8's gain whip will give me some signal out and the whip will withstand a beating when hitting tree branches .... and things of this nature.

Any thoughts out there? All suggestions welcome!!

73

ed

Mar 19th 2015, 15:04

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

The height limits vary by state.

http://www.dot.ca.gov/hq/traffops/engineering/trucks/trucksize/height.htm
Per the California Vehicle Code (CVC), no loads shall exceed a height of 14 feet. The CVC Height Section is 35250, and is copied below:

35250. No vehicle or load shall exceed a height of 14 feet measured from the surface upon which the vehicle stands, except that a double-deck bus may not exceed a height of 14 feet, 3 inches. Any vehicle or load which exceeds a height of 13 feet, 6 inches, shall only be operated on those highways where deemed to be safe by the owner of the vehicle or the entity operating the bus.

You have to be very careful about trees--after a heavy rain they can be much lower than normal. Similarly, trees not subject to traffic can be quite low.

Zack W1VT
ARRL Senior Lab Engineer


May 29th 2015, 18:22

Pine

Joined: May 29th 2015, 05:45
Total Topics: 0
Total Posts: 0
Hi Ed, Why not make use of a 1/4 wave ground plane. It may have slightly less gain than other mobile antennas but is not so easily
detuned by bending when traveling, is seldom affected by low trees and is preferred by critical XYL's due to its low visual impact.

73 de Pine, ZS6GST

.

Jul 26th 2015, 00:00

W9CMG

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I use an auto window regulator motor to dip my antennas on top of our "bus" for low objects. It's controlled from the drivers seat position.

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