Since you mentioned a rubber duck, I would assume you are looking for info on a 2 meter dipole.
First of all, a rubber duck is a very poor radiator.
Using a simple quarter wave groundplane would likely give you 6-10db gain in performance.
A dipole is a half wave length radiator and has about 2db gain over a quarter wave ground plane.
power handling is a matter of material used to construct the dipole.
Build it with #14 wire and feed it with RG8 coax and it should handle a full kilowatt.
a dipole at 2meters is approx 39 inches.
19.5 inches hooked to the center conductor, and 19.5 inches hooked to the shield.
By the way, Radio Shack sells a very inexpensive scanner antenna that also works well as a dual band base antenna  (2 meter and 440 )  $19.95 last I checked.
Hope this info helped
73  N8EKT              

First of all, never feel stupid for asking for help.
We all need help now and then.
As far as lightning and grounding are concerned, Lightning will take the path of least IMPEDANCE.
Your roof is invisible to lightning, and therefor offers little protection.
Besides, you wouldn't want your house set on fire by lightning trying to get to your antenna in the attic.
POLYPHASER is a great source of info on lightning protection and even offers publications and videos on the subject.
One KEY point not mentioned previously is that ALL grounds need to be connected to ONE single point ground.
This can't be stressed enough!!
This is where most damage comes from.
Your telephone, cable tv, antenna, and power ground have got to be connected to ONE and ONLY ONE ground point!
If this is not done, all the grounding and lightning arrestors in the world won't save you.
Hope this helps
73 for now
N8EKT

there are several issues to consider here.
one is the placement of a second lead acid battery.
extreme care should be taken to vent highly explosive
gasses from battery area.
an enclosed un vented trunk would be a disaster waiting to happen. one spark and boom!
as far as charging such a battery, it could be charged
via some fairly small conductors from your main electrical system.
however, you would have to install a diode to isolate the second battery from back feeding the main system.
you would also need to use a large current limiting resistor as well as proper fusing of conductors to prevent disaster.
in short, leave something like this to a professional.

i have used the diamond 500 hna antenna for repeater service and beleive it to be the best of the high gain antennas.
the most durable of the dual bands however is the hustler g6 270 it is stationmaster quality at a low price

for something cheap and ready to operate, radio shack
sells a scanner antenna for $20 that will exibit a good swr on both 2meters and 440
it is a 1/4 wave ground plane on both bands

in short yes. i have a remote control thermometer that also uses 433mhz.
but the 440 band isn't the first and won't be the last.
the 902-928mhz ham band has been over run with cordless phones, baby monitors, intercoms and the like for some time.  and i have seen wireless microphone on various ham bands.

unless you are using end mounted antennas, yes there is an interaction between a center mounted vertical beam and the mast pipe.
this can cause a pattern distortion in the beam pattern.
a fiberglass mast pipe would eliminate that problem.
as far as spacing between any antenna and any metalic
object should be at least 1/2 wavelength, but 1 wavelength at 2 meters is only 6 feet, so it's a better
idea to go with 6 feet.
I have had them all but no ham grade beam seems to compare in strength to a klm.
and klm's gain figures are not inflated like most others.

you would not be able to get a lot of isolation using horizontal separation.
however, if you could mount one antenna 20feet below
the other, you would get some 50-60db of isolation

Despite many esops-fables floating around the ham community, most circumstances don't call for the use of "deep cycle" or gell cell batteries.
The main difference in conventional starting batteries
and others, are the amount of times you can deep discharge the battery.
Car starting batteries if very large like a 31 series,
will provide all you need at a very low price.
Although a 31 series deep cycle battery may be found
for less than $70 if you do some looking.
As far as keeping them charged, there is nothing better than a regulated power supply with either current limiting or install a large wattage current limiting resistor in series.
the proper "float" voltage is very critical and for a lead-acid battery it is exactly 12.95volts.
any higher you will create too much gassing, any lower and battery will degrade.

Being an engineer, I won't advise you eliminate any electrical safety grounds for any reason!
This may get you killed!
R.F. grounding however needs to be as low impedance as
possible.
you should have as short and straight as possible a heavy ground conductor run from your equipment to a ground rod "system" consisting of multiple rods.
Grounds are not to be taken likely!
Should the transformer in your rig or a bypass capacitor short, 120volts may be present on the case of the equipment!
If you isolate or remove this third prong you or a loved one may be killed!
Consult the National Electrical Code for further.

My 20+ years in the two-way business says use a half wave nmo mount antenna in the middle of the roof
no ground plane needed.
Larsen or other "commercial" antenna is best