Any suggestions on a best place to mount an Outbacker 10-160 so I can
use it while moving down the highway?

Chris N7FNB

In article ,
DeLores Lamb, KD7ZAE wrote:

Any suggestions on a best place to mount an Outbacker 10-160 so I can
use it while moving down the highway?

I imagine it's going to depend to a fair degree on the motorhome. Not
having done it myself, and basing what I say on my fuzzy knowledge of
general principles, I'd say you have several sets of issues which will
require a tradeoff process. You need mechanical strength for the
mount, you need good grounding, you want the antenna to be clear of
electrical interference, and you probably want to be careful about the
height.

So - first principle is probably to figure out where you can put it,
so that it'll stay put and won't damage the vehicle.

Traditional mounting for this sort of antenna is often via an
insulated-shoulder ball mount attached to a side panel or other
structurally-sound part of the body. Motorhomes with today's thin
skins (I've heard the term "structural paint" used ;-) may not provide
a suitable location to drill - the wind-shear stress of a mobile
antenna might tend to "tear out" a ball mount on a thin panel.

One possibility is a mounting stud attached (via drilling, clamping,
bracing, etc.) to the luggage rack up on top. Another would be to
drill through a side panel (ideally, not far from part of the frame)
and install some sort of strong and rigid backing panel on the inside
to provide the necessary mechanical support. A front-bumper or
above-the-front-wheel-well mount is another possibility, depending on
the configuration of the m'ome.

For a good signal, you want the antenna to be high, and clear of the
grounded portions of the vehicle body - this will help keep your
losses down (and losses *will* be considerable with a short mobile
antenna). In order to avoid whacking the antenna too frequently (or
too hard) you'd probably want to keep the top of the antenna below the
statutory minimum height for bridges here in the U.S., which I believe
is 13' 6". You can probably get away with having the tip of the whip
up somewhat higher than this (it's flexible enough to bend), but I
think you'd certainly want to keep the top of the helically-wound
section of the antenna well below the "hits an overpass" height. The
Outbackers are flexible and tough, but there's no sense putting
excessive WHACK WHACK WHACK strain on the antenna, the mounting and
surrounds, and your nerves.

The great height of a m'ome thus presents a bit of a problem... if you
mount the antenna up above the body to get the biggest signal, it'll
probably top out well above the underpass height and you'll end up
banging it and occasionally knocking low-flying birds out of the sky.

This suggests that perhaps a wheel-well mount, or a front-fender mount
with an auxiliary base mast to get the antenna up to hood height,
might be a tolerable compromise. Unfortunately, this puts the antenna
near the engine compartment, and could lead to problems with ignition
noise during reception and RF jamming of the ignition during transmit.

Another compromise possibility would be to mount it partway up the
side panel (perhaps near the back). Part of the helical section would
be near the upper part of the side panel, which isn't great for
losses, but you should be able to get the entire whip and part of the
helical section up above the roof.

A third possibility is to reconfigure the antenna. Mount it fairly
high up on a side panel, near the back, with the helical section
sticking up to around 13' above ground. Don't install the standard
whip. Instead, make an adapter out of 6" of brass rod (same diameter
as the whip base) with a loop in the top. Solder a long, strong,
flexible wire to the loop in the top, stick the adapter in the antenna
and tighten the nut, and run the wire forwards above the roof to an
insulated attachment point at the front. The horizontal wire will
serve the same basic "capacity hat" role as the whip, and will give
the helical part of the antenna something to resonate against. You'll
have to completely re-tune the antenna - the flying lead will probably
end up going into different holes than you expect, and you may have to
fiddle with the length of the capacity-hat wire to achieve proper
resonance on any given band. You should still get good signal out of
the antenna.

Then, there's grounding. No matter where you put it, you should
connect the antenna base to the vehicle frame via a heavy braid (or
several in parallel). Don't depend on the coax to provide good
grounding. Even if you mount it to a metal side panel, run the braid
to a good ground post on the frame - side panels are sometimes rather
poorly connected to the frame, due to the use of structural adhesives
rather than bolts when attaching them to the body.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Howdy,

If you have a 5th wheel trailer, mount the antenna on the hitch. It's high and
the most solid part of your trailer.

73 de Jack, K9CUN

(JDer8745) wrote:
Howdy,

If you have a 5th wheel trailer, mount the antenna on the hitch. It's
high and the most solid part of your trailer.

73 de Jack, K9CUN

I've never seen a 5th wheel motorhome.

--
Mopar http://www.allpar.com/mopar.html
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"Steveo" wrote in message
...
(JDer8745) wrote:
Howdy,

If you have a 5th wheel trailer, mount the antenna on the hitch. It's
high and the most solid part of your trailer.

73 de Jack, K9CUN

I've never seen a 5th wheel motorhome.

It would have to have a pickup truck bed
in the back... could happen.
__
Steve
KI5YG
..

" Stephen Cowell" wrote:
"Steveo" wrote in message
...
(JDer8745) wrote:
Howdy,

If you have a 5th wheel trailer, mount the antenna on the hitch.
It's high and the most solid part of your trailer.

73 de Jack, K9CUN

I've never seen a 5th wheel motorhome.

It would have to have a pickup truck bed
in the back... could happen.

I suppose it's possible, they do make some slick motorhome/enclosed
car hauler combo's.

--
Mopar http://www.allpar.com/mopar.html
Go 40 42 12