[NLRS] Rover advice needed

[Dr. Gerald N. Johnson]

On 5/10/2015 11:20 PM, W. S. Mitchell wrote:
>
>
> Greetings,
>    This June, I am planning to be a rover in the ARRL contest, heading
> from Minneapolis (EN34) out to DN85 and back, in a two-rover pack with
> the team of K0BBC and W0ZF.  I'm comfortable with SSB and CW, and feel
> comfortable with using WSJT for FSK441 (haven't made a QSO with it
> yet, though).  It will be my first rover operation, and among the
> first few serious VHF contest efforts I've made.

I'd be inclined to start out locally, like the grids EN33, 34, 35, 43, 
44, and 45 or spend the entire time on the top of a tall parking ramp if 
I couldn't camp out at home.
>
> I plan to borrow the parental car (no holes are or may be drilled),
> and borrow a 1 kW generator (source needed!) so I can run a laptop and
> my Yaesu FT-857d at full power (stop-and-shoot).  Bands will be 6m
> (Moxon) and 2m (Arrow V/U satellite yagi).  While I would be a little
> interested in 70 cm, it complicates the antenna switching/feedlines
> and the polarization of the antenna (2m and 70cm are orthogonally
> polarized).  For simplicity I think 6m and 2m will be enough.

The laptop can be powered from 12 volts DC with the proper power supply. 
Saves generator and inverter noise. The 857 load can be covered by the 
alternator with the car engine running. Much less trouble than carrying 
a generator and setting it out each stop. The auxiliary power jack may 
not do a good job, and most cigarette lighter plugs are junk. So it 
needs a direct (and properly fused) battery connection.

The V/U cross polarized antenna could be used at 45 degrees and work 
both vertical and horizontal, with some loss on each band. Arrow does 
make a dual band LP that is the same polarization on both bands, but the 
pattern on 432 is poor because a 3/2 wave element tends to have a notch 
broadside and a cloverleaf pattern. It could be designed better, if the 
elements were V shaped, but I've not yet solved that mechanically well 
enough to survive weather or traveling.

A duplexor can be used to use separate antennas for the two bands with 
the single coax connector of the 857. I've been doing that here for a 
few years, with antennas on a roof tripod. Lately I'm not getting out 
well on 432, I suspect water in the duplexor, something I need to fix by 
June contest. I found by experiment and much analysis that there isn't 
much interaction between 2m and 432 yagis if they are at least a quarter 
wave apart for the high band. 
www.geraldj.networkiowa.com/papers/2012/HowCloseBa.pdf

When you are trying for 150 or 200 mile contacts, the antenna means 
everything.
>
> My plans for a mast are not yet finalized.  When I use the 6m Moxon at
> home, I have been using about 7' of 3/4" PVC lashed 4' up to the deck
> railing for my mast.  For the rover I am thinking I would use a
> Christmas tree stand to help support a sturdier mast of some sort (2"
> or 3" black ABS tubing?), but would want to then have an adapter of
> some sort to get to the 3/4" fitting needed for the Moxon.   Fittings
> to get the 2m antenna attached to the mast haven't been determined;
> lashing it to the mast with rope is an option, though not a very
> fast-deploying one.  An Armstrong rotator will be used.

ABS is sturdy stuff, better if its not foam filled thin wall. Roving 
last summer on 432 for the UHF contest I used a dual band halo in motion 
and a PVC mast for a small yagi while parked and held it with my hand 
out the truck cab window. I was able to keep the 8' mast with antenna in 
the back of the truck without disassembly.
>
> Apart from the logistics of mounting the antennas, I have some
> additional questions:
> * What if it rains?  Do you use some form of shelter for the generator
> to keep it dry, or do most rovers have a vehicle with a beefy
> inverter?
> * What are the good ways to route the feedline out of the vehicle if
> it is raining and having the window/door open isn't an option?

Bruce uses foam pipe insulation on the window glass. I tried that last 
year and it seemed to work just fine with LMR400 UF. Cut the insulation 
as long as the top edge of the glass when its open an inch or two. 
Squeeze it around the coax by closing the window. The foam will be 
displaced at the coax but will fill the gap otherwise.

> * During a contest, what is the typical FSK441 meteor scatter calling
> procedure?  I expect to be without internet access, so online
> skeds/spotting won't be of use to me.
>
> I'm also open to other advice which would be useful for a first-time
> rover.  This year my theme is going to be starting small and keeping
> things simple.  Setup and tear-down times need to be fairly small (15
> min?), because DN85 is a long drive away and there are a bunch of
> grids in between.
>
> For those of you in the Minneapolis area, I am interested in borrowing
> the following items for the operation:
> * 1 kW generator (+oil +gas can +rain shelter?)
> * PL-259 feedlines.  I have a 50' and a 100' of LMR-240, but that's
> longer than needed and more lossy than I like.

10 or 12 feet of LMR240UF isn't too bad a feed line. Ditto LMR400UF. 
Radio City has both in stock and the proper crimp connectors. The 
important thing I've found is to be very certain the foil is removed 
from the face of the end of the dielectric after cutting the dielectric 
to length. It shorts too easily if not well cleaned.

> * Better portable mast than described above (note: I don't have a
> trailer hitch on the parental vehicle)

For 10 G roving with my pickup that has a 7 pin trailer connector, I use 
that to charge the rover battery because that charging circuit is only 
connected when the engine is running so there's no chance of trying to 
use rover battery while cranking through a 30 amp wire. You could 
arrange a wire relay to do that by adding a pipe T between the engine 
and the engine oil pressure sensor and putting a switch that closes on 
pressure rise (NAPA has one) in the other side of the T to run a battery 
charging relay automatically. Or wire the relay coil to the accessory 
circuit which is usually not powered while cranking.
>
> If all goes well, and I return from my voyage in the Southern Ocean
> with the VK0EK expedition (http://www.vk0ek.org), I will see about
> putting together a presentation on being a first-time rover for the
> Aurora conference next year.
>
> Thanks and 73,
>    Bill
> AE0EE
>